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51 PINE ST.PDFiiiiiiiiiiiiii 12811 51 PINE ST ADDRESS: f:zoe TAX ACCOUNT/PARCEL NUMBER:_ B UILDING PERMIT (NEW STRUCTURE):_ ",;�o COVENANTS (RECORDED) FOR: CRITICAL AREAS: DETERMINATION:n Conditional Waiver E] Study Required F] Waiver DISCRETIONARY PERMIT #'S: DRAINAGE PLAN DATED: PARKING AGREEMENTS DATED: EASEMENT(S) RECORDED PERMITS (OTHER): PLANNING DATA CHECKLIST DA' SCALED PLOT PLAN DATED: SEWER LID FEE $: SHORTPLAT SIDE SEWER AS BUILT DATED: SIDE SEWER PERMIT(S) #:- GEOTECH REPORT DATED: STR-EET USE / ENCROACHMENT PERMIT #: FO WATER METER TAP CARD DATED: LID #: LOT: BLOCK: LATEMP\DS'Ps\Fomis\,Street File Checklistdoc TERRA, ASSOCIATESf �Jnco Consultants in Geotechnical Engineeriing, Geology .'and Environmental E�irth Science , s November 21, 2001 Project No. T-480. Mr. Ross Woods Triad Point Edwards 2801 Alaskan'Way, Suite 107 Seattle, Washington 98121 Subject: Preliminary Geotechnical Report UNOCAL Site Pine Street and Chinook Road Edmonds Washington Dear Mr. Woods: As requested, we,have. conducted a preliminary geotechnical engineering study for the subject project. The attached report presents, our findings and recommendations for the geotechnical aspects of project design and construction. Our indicates that the site is generially underlain. by medium dense to very densehative sand,, silty sand, sandy silt,'and laminatedto massive, very dense silt and/or hard clay. Fill lids been placed at locations across the site in thicknesses ranging from.'about 1 to-12 feet. The co-fisistene of the 'fill soil is variable, but I - I ' , . � y generally -appears -to have been derived from the'on-site soils. Much of the fill -we. observed contained organic material and/ordebris. We observed, light seepage of perched groundwater in several test pits at depths ranging from about 2.5 to 11.0 feet below the ground surface.' Iri our opinion, the subsurface conditions at the site are suitable for the proposed development of the property. Jn general, conventional spread footings may be used for -supporting the buildings bea m*g'6n undisturbed native soil or compacted structural fill. The slopes on'the sitelare. generally stable,- and the stability is-. not expected'to b6,, 7 affected by,th& proposed development. The uncontrolled fill. encountered on , the, site will not be suitable for directly,supporting structural loads or pavements. Con'ceptualplans- for'development'indicate'.sign'ificant. cuts in the uphill,�art of the site, adjacent to Pine Street. These'excavations Willmost likely need, to be provided:w'ith temporary,support during+ construction. 1'2525 Willows, Road-, Suite 101, Kirkland, Washington 98034 Phone'(425) 82.1 -7777 Fax (42 5) -821 -43 34 Mr. Ross Woods November 21, 2001 Once project plans have been finalized, we will conduct additional detailed analyses to evaluate impacts on slope stability and prepare final, recommendations for the geotechnical aspects of site,developmerit. We trust the information presented.is sufficient for your current needs. If you have any.questions orrequire' additional information, please call. Sincerely yours, TERRA ASSOCIATES, INC. John C. S Project I I/JI/0 Anil ta P.0 A Princi 17006' 49 GMT 3 ics� a Project No. T4893 Page No'. 11 TABLE OF CONTENTS, Pag� No. 1.0 Project Description ..... * ................................... ............................................ ................... I.,— I 2.0 'Scope of Work ...... ; ................................................................................. * ......................... 1 3.0 Site Conditions ............................................................ ........... 2 11 Surface ...................................................... ? ................................................ 3.2, Soils ................................................................................................................ ...... 3 3 3 Groundwater ...................................................................................................... .3 4.0 zards .......................................................... Geologic Ha .................. .............................. 4. 4.1 Erosion .......................... I ........................................................................................ 4 4.2 Steep -Slope..,.� ........................................................................................................... 4 .4.3 Landslide .......... : ............ ............................................................ 4 ......................... 5 4.4 'Seismic ... : ............................................ I ....... * ............................... ................. 5.. 5.0 Discussion and Preliminary Recommendations ........................................................... 5 51.1 General ............................................................ : .................................... ................ 5'. 5.2 Site Preparation and Grading ............................................................................. 6 5.3 Excavations ........................................................................................................ 7 5.4 Foundations ............................. ........................................................................... 8 5.5 Basement and Ret�iniiig Walls ............................................................................ 5.6 Slab-�on-Grade Floors ......... .......... ................................................................. 10 5.7 Drainage ................................................................................................ : .......... 10 -11 5.8 Utilities ....... 6 .............................................................................................. 5.9 Pavements ................................................................................. ...................... 6.0 Additional Services ............................................. 4 .......................................................... 11 7.0 Limitiations ......... .......................................................................................................... 12 Figures VicinityMap ......... ...................................................... ..................................... Figure 1 Exploration Location Plan ...................... 7 .......................................................................... . Figure 2 General Slope Fill Detail ............................ ............................................................... ........ . Figure 3 Appendix Field Exploration and Laboratory.Testing.; ...................................................................... Appendix A Preliminary Geotechnical Report - UNOCAL Site - Pine Street and Chinook Road, Edmonds, Washington 1.0 PROJECT DESCRIPTION We understand the project.will consist of a residefitial development. Detailed building and site development plans are currently not available. However, a prelin-iinary.,site plan by GGLO indicates the developm6nt will consist of 15 multi -unit buildings. We'und&rstand'that the -buildings, will be three to fou r stories, with daylight basements and attached garages. We expect that the buildings will be wood -framed, with lower floors constructed'at grade. We expect structural loads'will.be about five to,severi Icips per,linear,f6o't for continuous, beuing,walls. Column.loads maybe onth.e order,of 200.jcips.--, Our review of an unreferehced pKeliminary grading Ian, dated February 20,.200 1, - indicate p s that the planned site� development will require extensive. grading with cuts and- fills up.'to'�'about 20 and 30 feet, respectively. In addition, it appears that temporary construction cuts up to about 20 feet will be required'along the downgradient side of Pine Street. Proposed permanent cut and fill slopes are.s'hown with an -inclination of 2:1 (Horiz'o'ntal:Vertical). The recorfimendations contained in the following sections of this,repo'rt, are preliminary and are based'on'the conceptual'information described above. We should review design drawings as they become available -in order. to supplement or amend our recommendations, as required. 2.0 SCOPE OF WORK' On October 18 and'19, 2001, we excavated-17 test.pits to depths ranging froni 9.5 to 16.0 feet below existing. surface grades. In addition, we reviewed existing subsurface information from. previous -environmental studies at the'site to augment.the information obtained in our subsurface investigation. -Using this subsurface information, 9 we, performed analyses to develop preliminary geotechnical'�reconimendations for proje I ct' design and wing: construction. Specifically, this report addresses the follo Soil and groundwater conditions Geologic hazards and site stability .'Site preparation and grading Excavations Foundations November 21, 2001 'Project No. T-4893 Basement and retaining walls Slab -on -grade floors Drainage Utilities Pavements 3. 0' SITE CONDITIONS 3.1 Surface The project site is the *approximately 15-acre upper yard area of the UNOCAL Edmonds,Bulk Fuel Terminal located approximately between Unoco Road and Pine Street in Edmonds, Washington. The upper yard'area was formerly used as.a tank farm having 23 aboveground storage tanks (ASTs). All of the tanks and associated aboveground piping had been removed prior to our field investigation. The approximate location of the site is shown on the Vicinity Map, Figure 1. The site is situated on the upper. portion of a predominantly nbrth-facing hillside. An undated'site plan by Triad Associates indicates elevations in the planned development area range from about Elev. 170 in the south-central portion to about Elev. 70 in the*northeastem portion. Surface grades at the site have*been signi - ficantly altered for siting fuel tanks. In general, the fuel tanks were constructed on large excavations cut'into the hillside. The cut slopes are typically 15 to 20 feet in height with inclinations'of about 60 to 70 percent. The downgradient sides of several tank areas are enclosed by a containment berm constructed of fill.. The heights of the berms are about 6 to 12 feet above the bottom of the tank excavation. We' observed a tar -like coating covering'th6' surface of the berms and most of the interior slopes of the tank areas. s The western and northern margins of the planneddevelopment area are 'near the top of a steep natural slope. The topographic information provided to us indicates the slope is approximately 70 to 90 feet high, with inclinations ranging between. about 50 and 80 percent: The areas beyond the toe of the slope to the north-northwest are relatively flat UNOCAL yard and parking areas. Burlington Northern railroad tracks run along the toe of the slope to the west. Portions of the'slope have.been subjected to shallow erosion and localized sloughing; however, we did not observe indications..of deep-seated instability. Slope vegetation consists predoi-ninan'ily of young to mature deciduous trees and brush. The' portion. of the site located south of. P m*e Street is undeveloped forest except at the western'end, whiclids occupied by two small buildings located within a fenced enclosure. This portion of the.site slopes down to the north and northeast at grades. of about 20 'to 25 percent. Vegetation consists of predominantly of mature coniferous, and deciduous trees and brush undergrowth, Page No. 2 November 21, 20011 Project No. T-4893 3.2 Soils. The native soils encountered in the test pits consist of medium dense to' very dense na t iVe sand, silty sand,-san4y silt, and, laminated to massive, very. dense silt and/o'r hard clay. The soils we observed in the test pits are generally consistent with those described in the environmental studies performed at the site by others. We y encountered the very dense silt/hard clay underlying the medium dense to dense sand, silty sand, and sandy siltin eight,of the test.pits at*depths ranging from about 2.5 to 10.0 feet below1he ground surface. Test Pits TP-H, TP- 12, and TP-14 throu"h.TP-17 all*te'rminated in rnediurn dense to very dense sand, silty sand, or sandy silt. These .9 test pits are all. located at lower elevations in the northeastern to, eastern portion of the site.. The very dense silty sa I nd and sandy silt occasionally contained fine gravel and appeared glacial till -like. We observed'fill overlying the native soils in 11, of the' 17 test pits. T he fill soils consist primarily of, loose to fimi silty sand, sandy silt, silt, and clay, with,varying amounts of organic material and debris. The thickness of., the fill is,generally less than about three feet; however, we observed fills of 12 and 11 feet ffi Test Pits TP-6 and TP-16, respectively. Test Pit TP-6 was located on a berm between two large'tank. excavations., Test Pit TP-16 was located on the northeast -facing slcipd,'- below. the two large tank are -as in the I east I ern portion of the site. ln gener al, webbserved the original topsoil horizon beneath the fill, soils. The Geologic Map of the Edmonds East and Part bf-the Edmonds W�st QuadrOgles, Washington by James P.' Miniard, 1983, shows the soils at higher site elevations mapped as Ya§hoh till, Va§hon, advance outwash, and Transitional beds. Soils at-lowe r site elevations'are mapped as -medium- to coarse -grained sand of.the,Whidbey Formation. Transitional bed sediments are described by this' publication as massive to, bedded clay, silt, and fine to very fine sand. The soils encountered in the test pits are generally -consistent, With the- descriptions'. of transitional bed deposits. Detailed descriptions of the subsurface conditions encountered in'the test ogs pits are presented on the Test Pit L in Appendix A. The approximatetest pit locations are shown on Figure 3.3 Groundwater We encountered light groundwater seepage in.7 of-the-17 test pits at.depths ranging between about 2.5. and 11.0 feet. The seepage was generally perched 'on the very. dense siltihard clay, or on the denseto, very'den'se. glacial till -like silty sand/sandy silt. The groundwater conditions described above are typical for sites underlain by relatively impermeable' materials, such as 'glacial till and glacially consolidated silts and clays. Surface water will'infiltrate through the'upper sandy or weathered soils and become perched on the underlying, relatively impermeable material. When combined with a positive gradient, the groundwater will flow laterally along this contact, emerging at lower elevations as seeps'and springs. 'Perched groundwater levels and flow rates will:fluctuate.�seasonally.aiid-typic�lly.reach*their highest levels during and shortly following the wet winter months (October through May). We' did hot observe indications of significant groundwater, seepage onthe site slopes. Page No. 3 November 21, 2001 Project No. T-4893 4.0 GEOLOGIC HAZARDS 4.1 Erosion The Soil Conservation Service (SCS) has mapped the site soils as'Alderwood- Urban land complex, .2 to 8percent' slopes and Kitsap silt loam, 8 to 25 percent slopes in the upper southern portion of the site, and Alderwood- Everett gravelly sandy loams, 25 to 70 percent slopes in the area of the former tank farm and the' steep slope below the tank farm area., The soils we observed ifi the test pit generally conform with the SCS mapping; however, the very dense silt and hard clay observed in the former tank areas would better correlate with Kitsap silt loam, 25- to 50 percent slopes. The erosion hazards forsoil s classified as Alderwood-Urban land complex, 2 to 8 percent slopes and Kitsap silt loam, 8 to 25 percent slopes- are classified as slight and moderate, respectively. Alderwood-Everett gravellp sandy loams,'25 to 70 percent slopes is classified as having a moderate to high erosion hazard. The erosion hazard for soils classified as Kitsap silt loam, 25 to 50 percent slopes is considered high. The City of Edmonds defines erosion hazard areas as those areas containing soils that may experience severe to very severe erosion hazard. These soils include, but are not limited to, the following when they occur on slopes of 15 percent or greater: i. Alderwood. soils (15 to 25 percent slopes). ii. Alderwood-Everett Series (25 to 70 percent slopes) iii. Everett Series (15to.25 percent slopes) Based on the SCS'mapping, much of the site would be considered an erosion hazard area. We did not observe indications of significant active erosion in the planned development area; however, the soils will b * e susceptible to erosion when exposed during construction. Best Management Practices, (BMPs) must be used during construction to mitigate the erosion hazard. . If the'erosion control measures are'properly implemented and maintained, it is our opinion that the planned development will not adversely impact the erosion potential for the site or adjacent properties. All erosion and sediment control BMPs should conform to City of'Edmonds requirements. 4.2 Steep Slope The City of Edmonds defines steep slope hazard areas as any ground that rises at an inclination of 40 percent or ..more within a vertical elevation change of at least 20. feet. Based o n this definition and the topographic information provided to us,.the steep slope located below the development, area and the cut slopes on the uphill sideof several of the tank areas are considere'd steep slope hazard areas. The steep slopes located within the former tank farm area will be graded to inclinations of 2:1 or flatter. -It does not appear that site grading will directly impact the steep slope located below, the western and northern portions of the development are a*. We will evaluate potential impacts regarding.the steep slope hazard areas once final site grading information is developed. Page No. 4 NQvember2l-,2001, -4893 Project No., T 4.3 Landslide The City of Edmonds defines landslide hazard areas, as follows:- L, Any areawith slopes* of 15 percent or greater and imijernidable s6ils (typically silt'and clay), frequently interbedded witligranular soits'(pr6dominantly sand and gravel) and springs or groundwater. 2.. Any. are . a that includes areas with significant, visib . le ,evidence of 'groundwater., seepag e, which'also ificlud6s,existing. landslide deposits, iegardless.oif slopes. 3. Any area that has shown movement during the Holocent'epoch (from 10,000.y6ars ago to, present), or is' underlain by mass, wastage debris 6 f that epoch, as determined by.a qualified geologist. or geotechnical engineer. 4.- ',?sny area potentially. unstable as'a result of rapid stream incision or stream bank erosion. 51�. Any area. 16cated-.-on an alluvial fan, presently subject to or,poteniiall subject to, inundation by debris y flow or deposition of stream -transported sediments. Based on our observations of site soil* conditions'and the, above, definitio n*,' 'many of the site slo pes would be considered landslide hazard areas. , We expect that, the steep 'slopes located below, the western and northern portions of the development Area would also be. considered a, laridslide'hazard area due to soil, conditions*., Based on our.field observations, it does not appear that the.site slopes hav e been,subjected to deep-seated instability. An evaluation of Potential-. impacts of development and any 'necessary,, mitigation will',be made- after the site development plans h ' ave - been finalized. These'evaluations will, include additional subsurface exploraition-by deep _tesi-bo'n*ngs in are'as,of de'epexcavationsand near the top of the slope. 4.4 Seismic The P��get Sound area falls within. Seismic Zone 3,-as'.classified,by,the 1997. Uniform Building Code (UBC,). Based 'on the soil condition's encountered in our test pits land -described ifi-the environmental report by others, a soil pr9file type'of Sc, from; TableA64 of the 199TUBC -'should be used indesign. Liquefaction is a phenomenon wherethere is a',reductionor complete loss of soil.strength due to an in, water pressure induced 'by vibrations. tiqu�facfion'maihly affects geologically, recent deposits6f fine-grain6d sands that are below the'groundwater table., Based on,the soil and groundwater donditions'we encountered, it.is our opinion that the risk for liquefaction to occur in potential building. areas at this site'is negligible. 5.0 DISCUSSION AND PRELEMNARY RECOMMENDATIONS 5A General Based.on our study, it is our-opinio'n thatthe site',is suitable for the proposed development:. Buildings can-te supported'on conventional spread footings bearing'on competent native soils.below. the surficial topsoil- layer and/or uncontrolled fill, or -on structural fill -placed and. compacted. onihe'competent native,so'ils.� Floor slabs and pavements can b e similarly'supported Page No..5 November 21, 200 1' Project No. T-4893. U I I I The uncontrolled fill 'encountered should not be considered -suitable for directly supporting foundations or. slab - on -grade, floors. The existing fill we observed in the northeastern portion of 'the is at least 11: feet' thick in locations,, contains a significant, amount of'organic material, and does not'appear to have been placed 'in a controlled manner, on a properly prepared subgrade. To reduce, the 'potential' of unacceptable. differential settlements of the structures and to avoid impacting the stability of the fill s.lope in this portion of the 'Site, we recommend transferring building loads to comp&tent.native soils beneath the fill using deep foundations. Jn our opinion, a foundation system c,onsisting.o.f augercast piles or drilled piers Will provide.an economical and suitable .building support system.. Removing t�e uncontrolled fill and replacing it with an engineered structural fill pad is an-altemative to using a deep foundation system.' Because of. uncertain' ties in the consistency of the fill, there are risks that cannot.be quantified associated with constructing pavements, over.the existing.fill. Therefore, the existing fill soils should also be removed from pavement areas and replaced with structural fill. Much of the existing fill soils, ob . served at'the- site will not be suitable for-re'use-as structural fill because of - excessive organic material and debris. The native silty sands, silts, and clays,are moisture sensitive 'and will be difficult to compact as structural fill when too wet.- The. ability,to use thesoils from site excavation as structural fill will depend on' the Soils' m oisture content and the prevailing weather conditions at the time. of construction. if grading activities, will take place during the winter season, the owner, should be 'prepared, to import free - draining granula± material for useas structural fill and backfill. The following recommendations should be incorporated into the project design -drawings �tnd' construction 01 specifications. These recommendations are preliminary and, may be, altered or augmented upon. review of the fin,al plans. 5.2 Site Preparation and,Gfadin To prepare the site for construction,'all vegetation, organic surface soils, and other unsuitable materials including the existing fills should be stripped and removed from the portions of the site to be developed. Once clearing and grubbing operations are complete, cuts and- fills . . can be made to establish design grades. 'Prior to placing fill, we recommend prb6froll.ing all exposed surfaces to determine if any isolated- s6ft and yielding areas * are present. .. Cutareas that will - provide direct support for new construction should also be proofrolled. If excessively yielding areas are observed and, cannot be stabilized in place b - compaction, 'they. should be cut t6a y firm bearing'surface and filled to grade with. structural fill. If -the depth o f excavati on to remove.unstable soils is excessive, you can consider using- a geotextile fabric, 'Such as MiTafi- 50OX or equivalent, in conjunction with structural fill to limit the depth of removal. In general,'.a minimum of 18. inches, of a clean granular structural fill. ,.placed over the geotextile fabric should establish a stable, bearing surface., A representative of Terra Associates, Inc., should observe all proofrolling operations at the time of construction to, verify stable subgrades., Excavations up to about 20 feet below*t le existing ground surface are propose d along,the northern side of Pine Street in the southern portion of the site.' Based on our observations, and 'considering the . time of year our' I be required to complete the investigation was performed,' it does not appear that significant drainage efforts wil excavation as proposed. Howev er, this should be verified by,field observations at the time of -construction: Page No. 6 November 21, 200 1* Project No. T-4893, Most of the granular site soils contain a moderate percentage- of fir,ies (silt and clay particles), which, will make them sensitive to moisture. . The use of silt and clay. soils a's structural'fill may be possible during- dry Weather. 'However, it will, be'extremely difficult to. control their moisture content �and to'placd and compact- them satisfactorily. Some of the.site-soils are wet and will require drying to reduce their moisture,ontefit and,fac'ilitate compaction. Drying can be accomplished by aeration during,.dry weather conditions ori by the use of an additive such as cement kiln dust or Portland cement. if fill activities'.'must take place during wet Weather or- on a wet subgrad6, the owner should be prepariedto use wet weather structural fill. For this purpose, we. recommend using a. granular soil that meets the following grading requirements: U.S. Sieve -Size P6rcent Passing' 3 inches 100'' No. 4 75 maximum No. 200. 5 maximum* *Based on the'3/4-inch fta6tion. Prior to use,- Terra Associates, Inc. should examine -and test all on-s'ite or iinpoi-ted materials',proposed for.use as structural fill. Structural fill should be, plac'ed,in uniform loose layers not exceeding 12 inches,, and then compacted to a minimum of 95 percent of the soil's rna'ximum dr y -density,, as. determined by ASTM Test Designation D 6918 (Standard Proctor). Themoisture content of the soil at the time of compaction should be within two percent of its optimum, as determined by this same standard., In non-structural areas or for backfill in utility trenches below a. depth of 4 feet, the degree of compaction could be reduced to 90 percent.. E, mbanl'anent fills. placed on slopes exceeding a grade of 20- percent. must be key'ed-'and benched into competent native soils. A general slope fill, detail is shown on Figure 3. 'Subsurfac6 drais may also be required.. The need'for subsurface drains should be evaluated in the field at the time of construction. The proposed fill'areas should -be stripped of topsoil, duff, existing fill, soils, and soils containing organic material prior. tocreating horizontal benches for the placement of the fill. All permanent cut and fill slopes. should be graded .with a finished. inclination no greater, than 2: 1. Up on completion of grading, the sl ope fac e s . hould I be I appropriately . veg eiated or provided With other physical means to guard against erosion. Final grades at the top of the slope must pr6mote'surface drainage away from the slope crest. 5.3 .'Excavations All excavations at the site associated with'confined spaces, such as utility trenches and'lower building levels, must be' completed' in accordance with, local, State, or Federal requirements.: Based on current, Occupational Safety and Health Administration (OSHA) regulations, the. upper medium dense, to dense granular soils would be classified as- Group C soils. The.very dense silt and, hard play soils fall intd the Group -category. Page No. 7 November 21, 2601 Project No. T-4893 Accordingly, for temporary excavations more than 4 feet. and less than 20 fet deep, side slopes -in.Group C soils should, be laid back at a minimum slope inclination of.1.5:1. Temporary slopes in the Group A soils can be completed with a gradient of 0.75: 1. -If there is insufficient room to complete the excavations in this manner, or if excavations greater -than 20 feet 'deep are planned, temporary shoring may need, to be. used to 'support the excavations. The above information is provided solely for the benefit of the'owner and other design consultants and'should not be construed to imply that Terra Associates, Inc. assumes responsibility for job site safety.. Job site safety� is the sole responsibility of the project contractor. Based on the grading information provided to us, it appears that portions ofthe temporary,,excavation along -the northern side of Pine Street will require shoring. We recommend using a cantilevered soldier pile and timber lagging shoring system. We Will provide desi for temporary shoring once more details -are known gn parameters regarding fnal site grading.', 54 Foundations Spread Footings The buildings may be support ed on conventional spreadfooting foundations bearing on competen t native soils or on structural fill placed above competent'native soils, as recon imended in the Site Preparation and, Grading section of this report. Perimeter foundations should be placed at least 13 feet below final, exterior gradeg for frost protection. Interior foundations can be constructed at any'c'onvenient depth. On a prelim inary basis, foundations can be dimensioned for a'n6t allowable bearing capacity of 3,000 pounds per. square foot (psf), where supported by the medium dense to dense native soils, and compacted structural fill. Foundations supported by the very dense 'silt and hard clay soils can be dimensioned for a net allowable bearing capacit� of 5,000 psf. For short-term, loads, such as, wind- and seismic a one-third increase, in this allowable capacity pan be* used. With structural loading'as* anticipated -and these b earing stresses applied, estimated total settlements are about one, inch,with one-half to three -fourth inches diff6rential in nature. These settlements should be immediate in nature, occurring during and, shortly following application, of building loads. For designing foundations to resist lateral loads, a base friction coefficient'of 0.4 can be,U'sed. Passive. earth pressures acting on the side of the footing and bunie'd portion of the f6undation stem wall can also be considered. We recommend calculating this lateral resistance using an equivalent, fluid weight of 3 00 pounds per. cubic foot (pcf). We recommend not including the upper 121nches of Soil inthis.computation because it. can be, affected by weather or disturbed by future.gradifig'activity. 'This value assumes the,foundation will be constructed neat against competent native soil or backfilled with structural fill, as described in the. Site Preparation and Grading section of this report. The re.conun'ended friction and: passive value's include a safety, factor of 1.,5.. Page No. 8. N vember 21, 2001. o Project No. T-4893 Drilled Piles Where foptink elevations cannot, be readily lowered to the competent native sbil,:we.recomm6nd'siipp'6rting building, wall, and floor loads'on augercast pile's or drilled pier foundations that penetrate a minimum of five -feet into the native bearing stratum.. Allowable axial and lateral pile c�apaciti6s for'varying pile,.diameters are as foll6ws: Pile Dianietei (incli AllowaWe Axial Load% (tons) Allowable Lateral Load (tons)' 30 4 18 35 5 The above 'allowable axial 'capacities 'include a'safety factor,of 2.0.1 Full single, -pile capacities can be.used, provided pile spacing. is at least three pile - diameters. For, closer spacing, there will be a, slight reduction' in the 'allowable single -pile capacity due to group effects. The amount of this -reduction will -depend, -on the'/ number of. piles in the grouping and their spacing. 'We- antici that settlements un er the pile foundations will be less pate than on'e-fourth inch.. For augercast piles,- the pressure used to inject the grout, and construct the pile column will coiTi'press the soils immediately adjacent to the . pile. As a result, the amount' of grout needed to form the, pile may be greater than the' theoretical grout volume'. Als6� piles should- be constructed at'a minimum sp . acing of five diariieters.� 'Once the grout has achieved its initial set, installation betwedn'theselo,cations ca-n'be completed. The auger should be extracted slowl y out. Ifthe auger y and unif6iml below. a sufficient and consistent head'of gr is e tracted to' quickly, the pile may'neck down dn& soil, may collapse into- the p�le, reducing its. structural' iritegrity. , At a point along the,inj&tion - line,'the piling should use'a. pressure. gauge to monitor the X. grout pressure during construction.. The amount of grout�used in formin'' the pile,should'also"be monitored. 9� 5.5' Basement.and Retainin Walls,' The magnitude of earth pressures developing on basement or. retaining i�Valls will depend on the'quality and - '11. We recommend placing ac Compactiop* of thd.wall,backfi and compacting wall b i kfin a's'structural fill. Below,' improved areas, such as pavements or floor. slabs', the ba6kfill should be compacted to'a minimum- of 95.percent Of its maximum drytinit weight, as d6t6rrm''ned' by American Society of Testing and Matehals (ASTM Test' Designation' D-698 (Standard P�roctor). In uni' oved areas, the r6lat v c6on, can be reduced to'90 MPr i e compa. percent. To prevent hydrostatic pr� . essure development, wall drainage must be installed. Drainagd,behind basement walls,. can be provided by -attaching prefabricatedwall drainage panels, su'c' h.'as Mradrain - G100W, to - the. outer 'Side of the wall-, or, by backfilling the wall with a clean granular -material, such as pea, gravel., - A foundation drain consisting -of a four -inch diameter perforated PVC. pipe, should be installed at the base of the wall,fbi collection a d remo' I of the�- *intercept d gt ai n va e oundwater., The foundation dr' n should be "surroun'ded'by, at4east -six inches of pea gravel extending two feet above the pipe All drains must' to an appro-�ed 'point of contr Iled be routed. 0 discharge, Cleanouts should be. installed.. at. appropriate and easily�,;Iccessible' locations "along.,the drain alignments. These cleanouts shouid'be serviced at.lea.st'once'' each year., Page.No.,.9' November 21, �2001 Project No. T-4893 With wall bdckfill �placed and compacted as recommended and -drainage properly installed; we reconunend designing unrestrained walls for an active earth pressure equivalent to a fluid weighing 35 pcf. For iestrained walls, an additional uniforrn lateral pressure of 100 psf should be added. These values assume a horizontal backfill condition and that no other surcharge loading, such, as traffic, sloping embankments, or adjacent buildings, will act on the wall. If such conditions will exist, then the imposed loading shouldbe includ ed in the wall design. Friction at the base of foundations -and passive earth pres sure, will provide resistance to these lateral loadg. Values for these parameters are provided in the Foundations section of this report. 5.6 Slab -on -Grade Floors Slab-on-gra'de floors may be supported on subgrades prepared. as. recommended in, the Site Preparation_ and. Grading section of this report. Immediately below the floor slab, 'we recommend placing a f�ur-inch thick capillary break layer Of clean free -draining sand or gravel having less than three per -cent passing the No. 200 sieve. This material will reduce the potential for upward capillary movement of water through the underlying soil and subsequent wetting of the floor slab., Where moisture by vapor transmission is undesirable, a durable plastic ' membrane should be placed over the capillary break material. The I membrane should be covered with two inches of clean moist sand to guard against damage during construction and to aid in curing the concrete. 5.7 Drainag Surface Final exterior grades should promote free -and positive drainage away from the building areas. We recommend providing'a gradient of at least three,percent for a minimum distance of ten feet from the building perimeter,' except in paved locations. In paved locations, a minimum gradient'of one percent should be provided unless provisions are ilncluded-for collection and disposal of surface water adjacent to the structure. Surface water must not be allowed to flow uncontrolled over the crest of the site slopes and embankments. Surface water should be diiected away from the slope crests to a point of collection and controlled discharge�. If site grades do not allow for directing surface water away, from the slopes, then . water should be, collected and tightlined to the bottom of the slope in a controlled manner. Subsurface We recommend installing a continuous drain along the outside lower edge of the perimeter building foundations. The foundation drains and roof downspouts -should be' tightlined separately to an approved point of controlled discharge. Subsurface drainsmust be laid with a gradient sufficient to I promote positive flow to the discharge . point. All drains should be provided with cleanouts at easily accessible locations. These cleanouts should be serviced at least once each year. Page No. 10 November 21,2001, Project No. T-4893 A I � M 5.8 ' . Ufflities I I I I I I I I Utility pip(�� should be�bedded and backfilled in accordance with American Public Works Association (APWA) or Cit- e uld be placed and compacted as structural fill as described y of Edmonds sp cifications. Trench backfill sho in.the Site Preparation and Grading section of this report. If the granular soils excavated on -site are free of excessive deleterious material or debris, and are not excessively moisti they should be suitable for use as;backfill mateiial., The very dense silt and hard clay will not be suitable for. use as bac'kfill. If the silt and/or clay soils are exposed in utility trench excavations, or, construction takes place during periods of wet weather, it may be necessary to import, structural fill for backfilling purposes. 5.9 Pav�ments Pavements should be constructed on subgrades prepared as described in the Site Preparation and Grading section of this report. Regardless of the relative comp . action achieved, the subgra�6 must be firm and relatively unyielding before paving. Proofrolling the subgrade'with heavy construction equipment should be completed to verify this condition. The. appropriate thicknesses of the various components of* the pavem6nt depend on the subgfade soils and the traffic conditions to which the pavement will be subjected. We expect traffic to mainly consist of light passenger vehicles with only occasional heavy service vehicles. Based on this information and a properly prepared and stable subgrade, we recommend- the following pavement siections: Two inches of asphalt concrete (AC) over six i I n.ches of crushed rock base (CRB) Two inches of AC over four inches of asphalt -treated base (ATB) All paving materials should conform to the Washington State Department of Transportation. (WSDOT) specifications for Class B asphalt concrete, ATB, and CRB. Long-term pavement'Perf6rmance'will depend on surface drainage. A poorly drained pavement section will be subject to premature failure as a result of surface water infiltrating into the subgrade soils and reducing'their supporting capability. To improve performance, We recommend surface drainage gradients of at least two percent. Some-- longitudinal and transverse cracking of the pavement surface should be expected over time. Regular maintenance should be planned to, seal cracks when they occur. 6.0 ADDITIONAL SERVICES Terra - Associates, Inc. should, review the final -design and specifications in order to verify - that earthwoik and foundation recommendations have been, properly interpreted and incorporated into project design and construction. We should also provide geoiechnical services durin' construction in order to observe compliance 9 with the design concepts, specifications, and recommendations.' This will also allow for design changes if s surface conditions differ from those anticipated prior to the start of construction. Page No. 11 November 21, 2 001 Project No. T-4893 7.0 LMtATIONS, We prepar6d this report in.accordance with generally accepted geotechnical engineering practices.. This report is the' copyrighted propertyof Terra Associates, Inc. and is intended for specifit.application to the'LTNOCAL Site p r -is for the exclusive use of Triad Point Edwards and their- authorized representatives'.. No oject. This report other warranty, expressed or implied, is made. The analyses and preliminary recommendations presented in this report are based.upon,,data obtained from the on -site test pits. Variations in soil conditions can occur, ihe nature and exte.nt.of which -may not become evident until construction. If variations appear evident, Terra Associates, Inc.' should be rdque%ed to reevaluate the recommendations in this report prior to proceeding With construction. Pag eNo..,, 12 PC pt ST Sw 18 g w ell ST Sw Sw W. PL w Sw :CHERR 'ST 196T S W Mi�601Y 1� PU E7 wy 0 k), BROOKNERE NIRDL -EMOND'S All. DR '7� kS UNDERVA TER PEkS ST um PARK, LL_5R F7 TER.LM W' VISTA a wy.t ZOR i� SW S . T ST I WDIAG �WH .1124i ST kGUE I _HIU 7w ELL F-1 ST I N "�377 -, ST PL Sw f -1-' 1 DAYTON 't . OFN PL MAPLE 144RINA MWMM P L �P UNION w %of 1&�Al OIL y WY11. 212TIt 1-5 1 �Cuw nw� , SITE. 7 �;T SPAIXEAfv, 7 I 7�.. ST EDWARZ KARIM PT RE40 'OS Re Sw a 1!. FIR 'r IN .1 MTH ST Pi Sw 26 8ELLA . COOLA 30�� "N7 606D4 ST Sw 0, BIRM .!IR PL PC 22UT PL M-1 AMI IRK SOURCE: Thomas Guide, Pierce, King and Snohomish County, 1999., Page 454.,' NOT TO SCALE VICINITY, MAP. f Te'rra.' UNOCAL SITE &&& Associates, Inc. EDMONDS.,* WASHINGTON Proj. No. T-4893 Date NOV 2001,' Figure 1 Geotechnical Consultants L. ' I 7WV - 2 'SB-132o -71--'-�'i--��; B 2 CP -4- SB-217, .10 -203 TPA SE�2 9 M �SB-�220: 2 -0 -12 4P eSB-214--�_ -202 S&-23� SB-216 14 p -5 B-211 IgT P TP-' -31 13- P-1 5 ':z B-210 QB-231 o' B 2 3 P-1 P71 SB-223. -vj r X �S13-229:,*:- S6-206 B-222 2 8 a -23 S 2 -17 7 TP TP-10 SB-2. S13-2 C:I SR-2 P-8 �tp B -20 SB-22;f —y TP- NOTE: LEGEND THIS SITE PLAN IS FOR REFERENCE PURPOSES ONLY AND 19 TP-1 APPROXIMATE TES I T PIT LOCATION (TERRA) IT SHOULD NOT BE USED FOR CONSTRUCTION OR DESIGN EMCON EXPLORATORY BORING PURPOSES. EXPLORATION LOCATION PLAN Terra UNOCAL SITE REFERENCE:, 0 200 .400 EDMONDS-, WASHINGTON I Associates, Inc. SITE PLAN PROVIDED BY -TRIAD ASSOCIATES Geotechnical Consultants APPROXIMATE SCALE IN FEET Pr0j. No. T-4893 Date NOV 2001 Figure 2 2 B TOE OF, NEW SLOPE 2' 6' ­4 A B tST!NG 2' LOPETOE TYPICAL SLOPE BENCH (MAY A REQUIRE SUBDRAIN IF SEEPAGE CONDITIONS ARE INDICATED) 6' A, TOE BENCH CUTAND' 6' ­4 DRAIN (SEE NOTE 1) KEYWAY AND DRAIN (SEE NOTE 1) NOT TO SCALE. NOTES: 1) DRAINS SHALL CONSIST OF 6" DIAMETER PERFORATED PVC PIPEENVELOPED IN 1 cu. ft. OF WASHED 3/4* MINUS DRAINAGE GRAVtL 2). & TOPSOIL REMOVAL THICKNESS BETWEEN XEYWAY AND BENCHES. (IF NECESSARY) VERTICAL ELEVATION DIFFERENCE BETWEEN TOP OF LOWER BENCH BACKCUT AND UPPER BENCH ELEVATION., GENERAL SLOPE. FILL DETAIL Terra . UNOCAL SITE Associates., Inc. EDMONDS WASHINGTON @PG�otechnical Consultants Proj.No. T-4893 Date NOV igure 3. 2ooTiF APPENDIX A FIELD. EXPLORATIONAND LABORATORY TESTING UNOCAL Site. Ednionds, Washington On October: 18 and 19, 200 1, we performed our field exploration using a track -mounted, excavator. We explored subsurface soil conditions at the -'site by, excavating 17 test pits to a maximum depth , of about 16 feet. below existing surface grades. The test pit. locations are shown on Figure 2. The test pit locations were approximately determined by pacing fro 'in existing surface features. The Test Pit Logs are presented on Figures A-2 through A- 10. An engineering geologist from 6ur office'n ain'tained a log of each test pit a's it was exca�ated, classified the soil -conditi , ons encountered, and obtained representative. samples. All soil 'samples were visually classified - in accordance: With the.Unified Soil Classification System.' A copy of this *classification is presented as Figure A-L �.Representative soil. samples obtained froR the test pits. were placed, in sealed plastic bags and. taken to our laboratory-. for further 'examination and testing. The 'moisture content of each sample wag measured and is reported on the Test Pit Logs: T,he Atterberg limits of four s4inples were determined and are reported on the Test Pit Logs. Grain size analyses.were performed on 11 of the samples,'- the results of whichare sh I own on Figures A- I I through A- 16. project No. T4893 -MAJOR DIVISIONS., LETTER SYMBOL TYPICAL DESCRIPTION Clean GW Well -graded gravels, gravel -sand mixtures, little or no GRAVELS Gravels fines.' GP Poorl�-graded grave.isi gravel -sand mixtures, little or (less than N More than 5% fines) no fines. GM Silty gravels, gravel -sand -silt mixtures, n.on-plastic U) 76-*0 .50% of coarse fraction is (D > Lj .6., 0) larger than No Gravels with fines. fines. co Z_ E 4 sieve GC Clayey gravels, gravel -sand -clay mixtures, plastic fines. < cc 0-00 (!3 C) 04 Clean SW Well -graded sands, gravelly sands, little or no fines.­ LO - 0 SANDS Sands SP Poorly -graded sands or.gravelly sands, little or no fines. LLI q Z U) co More than (less than- 5% fines) < co .2 = 50% of coarse 'mixtures, C) 0 fraction is Sands SM Silty sands, sand -'silt non -plastic fines. smaller than SC Clayey sands, sand -clay mixtures, plastic fines. No. 4 sieve with fines ML Inorganic silts, rock flour, clayey silts with slight, SILTS AND CLAYS plasticity. CL Ino rganic clays of low to, medium plasticity, (lean clay). — 00 0 — CM CIS E 0* Liquid limit is less than 50%. _.. Z.N W OL Organic silts and organic clays of low plasticity. z -C (D (a MH Inorganic silts, elastic. SILTS AND CLAYS 2 co E CH Inorganic clays of high plasticity, fat clays. z 0 V) Liquid, limit is greater than 500/6' OH �'Org4nic clay's of high plasticity. HIGHLY ORGANIC SOILS PT Peat. DEFINITION OF TERMS AND SYMBOLS' U) U) St a*ndard Penetration Density Resistance in, Blows/Foot 2" OUTSIDE DIAMETER SPLIT W SPOON SAMPLER _j z 0 Very loose 0-4 2.4"'INSIDE DIAMETER RIN0 SAMPLER F5 Loose 4-1 O� OR SHELBY TUBE SAMPLER W Medium dense 10-30 0 Dense 30-50 3E WATER LEVEL (DATE) Very dense >50 Tr' TORVANE READINGS, tsf Pp PENETROMETER READINa1sf Standard Penetration W Consistency Resistance in. blows/Foot DD DRY DENSIT�; pounds per cubic foot > Very soft �0-2 LL LIQUID LIMIT,'perce int., W Soft 2-4 1: 0 Medium stiff 4-8 PI PLASTIC INDEX 0. stiff Very stiff 8-16 16-32 N STANDARD PENETRATION,. blows per -foot, Hard >32 Terra UNIFIED SOIL CLASSIFICATION SYSTEM UNOCAL SITE Associates',. Inc. 'EDMONDS, WASHINGTON Geotechnical Consultants �roj- No. T-4893 Date NOV 2001 T Fig Test Pit No. TP-1 Lo' �e1gJCS Approximate Elev. 104 Date 11 01 Moisture Depth, Content Soil Description N 0— FILL: crushed rock surf acing ove r brown to gray silty sand to sandy silt, fine grained, firm, moist. (SWIVIL) Rusty brown silty SAND medium dense, moist, with occasional fine (, fine grained \gravel and fine roo s. M) Gray.to mottled gray silty SAND, fine grained, medium dense to, dense, 5 moist, with occasional fine gravel. (SIVI) Becomes light brown at approximately 6 feet. 26 101— Gray CLAY, hard, moist, massive. (CL) Pp = 4.5+ tonsfie ILL 35.8 P1 15 15— Test pit terminated at 14 feet. No groundwater seepage. 20 Test Pit No.- TP-2 Logged by: JCS Approximate Elev. 124 Date: 10/18/01 Moisture Depth Content (ft.) - I - Soil. Description. N 0— FILL: crushed rock surfacing over brown siltysand to sandlysilt, fine grained, firm, moist. 4-Inch thick organic layer at base. (SM/ML) (Old topsoil horizon) Brown silty SAND, fine grained, medium dense, moist. (SM) Mottled grayish -brown silty SAND, fine grained, medium dense, moist. .20 (SM) 5 Grayish -brown silty SAND, fine grained, medium,dense to dense, moist. (SM) .10— Gray CLAY, hard, moist, laminated with Ii g ht gray silt, partings. Pp 4.5+ tons1W 37 .15— Test pit terminated at 14 feet. No groundwater seepage. 20 TEST PIT LOGS'' Terra UNOCAL SITE Associates, Inc. EDMONDS,. WASHINGTON Geotechnical Consultants 'Proi. No..T-4893 0 1 1 Figure A-72 I Date NOV 2 0 Test Pit..No. TP-3. Logged by: JCS Approximate Elev. 121 Date: , 10/18/01 Moisture Depth Content Soil Description 0 FILL: brown silty sand, fine grained, firm, moist with occasional fine, gravel and.organic material. (SM) (Hydrocarbon, odor) Dark brown organic silty SAND, fine grained, soft, moist to wet. (OL) 7 (Old topsoil horizon) 15 5— Tan'to light gray silty CLAY to clayey SILT, hard, moist. (CUML) (Hydrocarbon odor). 10 Gray CLAY, hard, moist, laminated with partings of light gray silt and gray fine sand. (CL) Pp 4.5+ 32 tons/fe Test pit te - rminated at 13 feet. 15— Light groundwater seepage from point source at 4.5f6et. 20 Test Pit No. TO-4- Logged by: JCS m -92 Approxi 'ate Elev.. Date: 10/18/01 ture Depth Mois Content Soil Description M FILL: light brown silty sand, tine gra = irm dry to moist. (SM) thick organic layer at base. (Old topsoil n) Light. brown.to tan silty SAND, fine grained, medium dense to dense, dry-. (SM) Mottled grayish -brown silty SAND, fine grained, medium dense to dense, 29 .5 moist. (SM) LL = 42.7 Light grayish -brown to light brown CLAY,and SILT, hard, moist, laminated 29 PI - 19.7 with partings of dark gray fine sand. (CUML) PP = �.S+ tonstie 10— Gray CLAY,.hard, moist. (CL) -4.6+ 29 I'PtponW Test pit terminated at.1 3 feet. 15— Trace groundwater seepage at 6 feet. 20. TEST PIT, LOGS Terra UNOCAL -'SITE Associates,'In' EDMONDS, WASHINGTON cle TD. Figure A-3 Geotechnical Consultants Proj. No. T-4893 ate NOV 2001 Test Pit No. TP* 5 Log �e.1dobyjCE5 Approximate. Elev. 110 Date 11 0 Moisture Depth Content SoiI.Description N 0 6 inches DUFF and TOPSOIL. Light brown SAND with silt'to silty SAND, fine grained, medium dense, moist., (SP-SWSM) 23 .5— mo'ttled grayish -brown SAND to SAND with silt, fine_,graihed, medium - denso to dense, moist. (SP/SP-SM) Becomes wet at approximately feet. 26 10,— .34 LL - 44.5 P1 = 21.3 q Grayish -brown to gray CLAY, hard, moist,-gdnerally massive, with occasional thin of gray silt. (CL) Pp 4.5+ tons/fe - 15— Test pit terminated at 16 feet. Light groundwater seepage between 9 and 10 feet. 20 -Test Pit No. TP=*6 Logged by: JCS Approximate, Elew 150, 1.0/18/01 Date. Depth Moisture Content Sol! Description, _N 0- - FILL: brown to grayish -brown SILT; CLAY, and fine.grained SAND,.firm - moist.to wet, with some fine gravel And occasional organic material. 32' 5 FILL: gray to brownish gray silt,'clay, and,fine grained sand, firm; moist to, - wet, with moderate organic material (including wood debris) And some g�avel. 12-inch thick organic layer at base. (Old topsoil horinn) 10— Gray silty. SAND to sandy SILT, fine grained,'deinse,'moist, -with occasional fine to coarse gravel. (SWML) (Glacial till -like) Test pit terminated at 16 feet; N6 groundwater seepage. 20 JEST PIT LOGS Terra UNOCAL SITE Assoeiates, Int. EDMONDS, VASH I NG.TON Geotechnical Consultants,. -48 1 93 Figure A-4 Proj.' No. T. Date -NOV 200i TP-7 Test Pit, Nom Log �ejdoby: JCS' Approximate Elev. 12.1 Date 118/01 Depth Moisture Content Soil Description' (6/0) 10 15 20 Logged by: JCS Date: 10/18/01 Depth (ft.) 0- 5 10 15 FILL: dark brown organic silty sand, fine grained, firm, moist. Mottled gray to brown SAND with silt to siity.SAND, fine grained, medium dense to dense, moist., (SP-SM/SM) (Hydrocarbon odor) 20 Tan. to light grayish�-brown silty PLAY to CLAY, hard,'moist,,occasional 24 mottling. (CL) Pp - 4.5+ tons/te 31, Test pit terminated at 15 feet.., No groundwater seepage. Test Pit No. TP-8. Approximate Elev. 121 Moisture Soil Description Content FILL: light brown to graysilty.dand, firm, moist to wet, with organics. FILL+: dark brown organic silty sandjoose, wet, with significant wood debris (timbers and branches). 2.5-foot diameter boulde'r., Gray SILT to SILT with sand, fine grained, dense, moist to wet. (ML) 2� Light grayish -brown to tan sandy SILT, fine grained, very dense, moist, with occasional fine gravel. (ML) (Glacial till -like)' 16 - Test pit terminated at 15 feet. - Light groundwater seepage at 6 feet. 20 TEST PIT LOGS Terra UNOCAL SITE EDMONDS,, WASHINGTON Associates, -Inc.. Geotechnical Consultants Proj. No. T-4893 Date NOV 2001 Figure A-5 Test Pit 0., TP-9 Logged by: JCS Apptoximate Elev. 150 Date: 10/18/01 Moisture Depth Content' Soil Description N - FILL: crushed rock surfacing over grayish -brown sandy'pilt and clay, firm, - moist. 6-inch thick organic layer at base. (Old topsoil horizon) Mottled grayish -brown dandy SILT to sandy CLAY, stiff, moist. (MUCL), Pp 4.5+ 30 tonrife 37 -'Grayish-brown CLAY, hard, moist, massive. (CH) LL = 58.8 P1 = 30.1 Pp = 4.5+ Gray SILT and CLAY, hard, moist, with occasional laminations of gray fine sand. (MUCL),' 1 22 1 tons/fe Test pit terminated at 15 feet. No -groundwater seepage. -Test. Pit No. TP-1 0 Logged by: JQS. Approximate Bev'. 157 Date:, 10/18/Oi Depth Moisture Content Soil.-DeScription N. . . 6 inches DUFF and TOPSOIL. Brown sandy SILT, iine grained, mediurn dense, moist. (ML), 40 Grayish -brown SILT and CLAY, hard, moist. (MUCL) Pp 4.54. tonstW Gray SILT and.CL.AY, hard, moist. (MUCL) - Test pit terminated at 15 feet.. - No groundwater seepage. 'TEST PIT LOGS' Terra UNOCAL SITE Associates, Inc., EDMONDS, WASHINGTON Geotechnicall Consultants _T Proj. No. T-4893 Date NOV 2�01 Figure A-6 Logged, by: JCS Date: 10/18/01 Depth ft.) 0— .5 10 15 Test Pit -No. TP-1 1 Approximate Elev. 78 Moisture Soil Description' Content - - Mottled grayish -brown SAND to SAND with silt, fine grained, medium dense, moist to wet. (SP/SP-SM) 25 15 - Light brown silty SAND to sandy SILT, fine grained, medium'dense to . dense,moist. (SWIML) Increasing silt with depth. 15 22 - Test pit terminated at 15 feet. - No groundwater seepage. 20 Logged by: JCS Date: 10/18/01 Depth, (ft.) 0- 5 1C 15 Test Pit No.-TP-12 Approximate Elev. .76 Moisture Content Soil Description.- . (%) nc es crus e rock'surfacing. - - Mottled grayish -brown SAND, fine to mediu�grained, medium dense, moist, with occasional fine gravel. (SP) (Hydrocarbon 03 Gray SAND with silt to SAND, fine grained, medium dense to dense, moist to wet, with occasional fine to coarse gravel. (SP-SWSP-) 17 15 Mottled grayish -brown silty SAND with gravel to sandy SILT with gravel, fine sand, fine gravel, dense to,very dense, moist. (SM/ML) . , (Glacial till -like between 8 and 10 feet) Increasing gravel with depth. 20 Test pit terminated at 15 feet. Trace groundwater seepage at 8 feet. I a TEST PIT LOGS ,Terra UNOCAL SITE EDMONDS, WASHINGTON Associates, Inc. Geotechnicai Consultants Proj. No. T-48193 FD;te NOV 2001 1 Figure A-7 Test Pit Non TP-1 3 Logged by:;JCS Approximate Bev. 86 Date:1.0/18/01. Moisture Depth, Content Soil Description.. MY 0- 12 inches crushed rock surfacing. Mottled grayish -brown silty S.AND to sandy SILT, very dense, moist. (SM/ML) 25 ydrocarbon odor) 31 Bluish -gray CLAY, hard, moist, with partings of gray -fine sand and light grayzilt. (CL). PP 4.5+' tons/fe 10- 15 Test pit terminated at 14 feet. Trace groundwater seepage at 2.5 feet. 20 Test, Pit,.No. TP-1 4 Logged by: JCS Approximate Elev..16 Date: 10/18/01 Moisture Depth Cont I ent -Soil Description, 0— FILL: bluish -gray silty sand with gravel to sandy silt with gravel, fine sand, fine gravel, medium dense to dense, moist. (SM/ML) 10 5— Light brown sandy SILT, fine grained, d ' ensei"moist, with occasional fine gravel and thin layers of -fine grained silty sand. (ML) 19 10- 15 15— Test pit terminated at 15-feet. No grdundwater seepage.+ 2.0 TEST, PIT LOGS' Terra ...UNOCAL SITE EDMONDS,, WASHINGTON, Associates-, Inc. Geotechnical Consultants 'Proj. No. T-4893 te NOV 2001 Figure A-8 Da Test Pit No. TP-1 5 Logged by: JCS Approximate Elev. 86 Date: 10/18/01 Moisture Depth Content Soil Description. N 0 5 10 " . 15 20 FILL: gray sil sand to sandy silt, fin grained, medium dense, moist, with occasional finegravel. ( W L). Dark brown organic sandy SILT,'fine grained, firm, moist, with occasional roots. (OL) (0 d topsoil horizon) Mottled grayish -brown silty SAND with gravel to, SAND with silt and gravel, fine sand, fine to coarse gravel, medium dense to dense, moist. 10, (SWSP-SM) Becomes brownish -gray and moist to wet at approximately 8 feet. V Brownish -gray silty SAND with gravel to sandy SILT with'gravel,:fine sand, fine graveli dense, moist.. (SM/ML) ( Glacial till -like) 18 - Test pit terminated at 1 5 feet. - Trace groundwater seepage at 11 feet. . N Test Pit.. No.' TP-1 6 Logged by;.JCS Approximate Elev. 68 Date: 10/18/01 Moisture, Depth -Content Soil Description 0- - FILL: gray to brown silty sand with gravel, fine'grainedj firm to loose, - 'moist to wet-. (SM) - FILL: grayish -brown silty sand with gravel, fine grain ed*, firm, moist to wet, 'with significant organic soils and wood debris. 23 110— 16 --"Bluish-graysil SANDwith ravel to sandy SILT with gravel, fine sand, fine gravel, dense, moist. 7S-M/ML) (Macialtill-like) Light brown SAND. fine arained. medium dense to dense, moist. (SP) 15 15— Test pit terminated at 13 feet. No groundwater seepage. 20 TEST PIT LOGS Terra UNOCAL SITE Associates Jnc. EDMONDS, WASHINGTON Gootechnical Consultants __F�i7gure A-9 Proi. No. T-4893 I Date NOV 2001 Test Pit No. TP-1 7- Lo' �elolyjcs. Approximate Elev. 82 .Date,, 11 01 Moisture Depth Conten't 'Soil Description 0 Ru%brown silty SAND with gravel, fine sand, fine to coarse gravel, Marl m dense. moist'. (sm) —moffied grayisn-brown silty SAND with gravel, fi`F6_s_a_n_d,1ine to coarse gra-v-eF,— medium dense to dense, moist., (SM) 13 Grayish -brown silty SAND with gravel to sandy SILT with gravel, fine sand, 5— fine - t6coarse gravel, dense to very dense, moist. (SWIVIL) (Glacial till -like) Sand content increases with depth.- 10 Test pit terminated at 9.5 feet.' No groundwater seepage. 15- 20 TEST PIT LOGS Terra UNOCAL SITE Asso'ciates,,Inc., EDMONDS, WASHINGTON Geotechnical'Consultants Proj,.. No.7-4.89& I Date NOV 21,001.1 Figu e A-1 0, A_ nc. TERRA ASSOCIATESf Consultants in Geotechnical Engineering, Geology and Environmental Earth Sciences F _-P u;_; 1�;.�� 'AUG -14 21006 BUILDING DEPARTMENT ciTY OF EDMOND$ July 36,.2003 Project No.T-4893 Mr. Ross Woods Point Edwards, LLC 2801 Alaskan Way, Suite 107 Seattle, Washington 98121 S ubj ect: Supplementary Subsurface Exploration Point Edwards Condominiums Pine. Street and Unoco Road Edmonds, Washington References: I Geologically Hazardous Areas.Review, Point Edwards Condominiums (UNOCAL Site), -prepared by Terra Associates, hic., dated J�nuary'.20, 2003' 2. Preliminary Geotechnical Report, UNOCAL I Site, Project No. T-4893, prepared. by Terra Associates, hic., dated November 21, 2001 Dear,Mi., Woods: As requested, we have completed supplementary subsurface.exploration at the subject site.. The purpose. of our. study is to ev I aluate the need for temporary shoring during construction of the propose&buildings, and to provide recommendations for temporary shoring design and construction- where needed. '-We previously perfonned geotechnical studies for the project and presented our findings in the referenced, reli . joft z s, however I , since that time, building locations And , site . grading have'been refined.. Triad Associates provided. us witha: current topographic, site plan dated July 21, 2003 that shows existing to ography and proposed site grading. Our current study focused on areas where significant, site excav6:ti6ns will le required, adjacent the downgradieni (northern) side of Pine Street, in',the areas 6fl,Buildings 3, 4, and � 8 � and the area of Building 5, located north of Building 8 and the private loop. road. Pine Street is currently one of two mmun-Ity. of Woodway,:south Of the, site. This report summarizes �the results roadways that access the co ornmendationsfor the of our: recent substwface exploration and discusses supplementary shoring rec project. FN Y.11 IFILE "MME W Asi rug&. I n 12525 Willows -Road,,Suite 101, Kirkland, Washibgto . 98034 Phone (42�) 821-77-77 Fax (425) 821-4,334 -Mr. Ross Woods7 July 30, 2003 We encountered perched groundwater in all three of.the recent bon'ng§ near the interface of the surficial fill/silty sand soils and the underlying viery 'stiff to hard clay, and in thin sand layers within * the very stiff to hard clay. We also observed indications of localized ligh t seepage from the face of the existing slope between proposed Buildings 4 and 8. The perched groundwater encountered in Borings B- 10 1 and B- 102 occurs. at elevations at least 15 feet below the lower elevations of Buildings 3,and 4 (Elev. 10 1. 17 and Elev.. 100.66, respectively). Boring B 1 :103 (drilled in the area of Building 8), encountered't,�vo levels of perched- groundwater. The upper perched groundwater level is approximately 8.5 feet below the ground'.surface (iipproxitnately Elev. 120.5), and the lower level is approximately 22 feet below the ground surface (approximately Elev. 107). The proposed elevation of the lower level for Building 8 is Elev. 111.67.' Fluctuations in groundwater seepage. levels should be expected. on a seasonal and annual basis. Typically, groundwater. seepage reaches maximum levels during and following the wet winter months, and diminishes or is completely absent during the dry summer months. We did not observe groundwater seepage in Test Pits TP-1 and TP-2 (located in the areas of Borings B-101 and B-102, respectively), which were excavated t6 a d,epth of about 14. feet in mid -October, 200 1. DISCUSSION Based on our review of existing -topography, proposed grades, and the planned building -elevations, it appears that temporary, shoring will be required I to complete the southwestem portion- of the excavation for Building 4. Soils encountered in Boring B-102, in the southwestem portion of Building 4, consist of approximately 13 feet of very loose to medium dense fill and medium dense native -silty sand overlying very stiff to hard clay. As discussed in our referenced geotechnical report, the loose to medium dense fill and native, silty sand soils'. Aould' be laid back at. a minimum- I slope inclination of 1.5:1 (Hofizontal:Verti.cal). Temporary. slopes in the very stiff to hard clay can be.completed with a gradient of 0.75: 1. Based on the -depths that we encountered. these soils in Boring B-102, excavations doMpleted to these temporary inclinations at the southwestem.. comer of -Building 4 would encroach about 40 feet into the Pine Street right-of-way and about 16 feet into ihIe.existing paved roadway. Excavatiorf to the' proposed lower floor elevation 'in the sotithwestem portion of Building 3 wilLexpose primarily medium dense silty sand with varying amounts of gravel. Temporary excavations'in these, soils that are graded to I an inclination of 1.5 1will extend about 27. feet into the'Pin& Street right-of-way at the southwestem. comer of the building, but would not en6rdach ii�to -the existing roadway. The soils in the area of Building-8 consist of existing.fill,native silty sand, and very, stiff clay/dense silt. - Based on the information provided to -us, it appears that temporar.y.excavatibris for Building 8 -that are sloped to an inclination of 1.5:1 will not encroach into the Pine _Streetlright�of�way. We expect that the, lower portion of the excavation for Building 8 will e�xposed vei-j stiff clay/dense silt, and may be graded to a� temporary inclination of 9.75.: L Project -No. T-4893 Page NoA Mr. Ross Woodg' July 30, 2003 Subsurface information obtained from our previous geotechnical studies indicates that the soils near the p western si . de of Building 5'consist of existing fill andhative, medium dense silty sand to approximately Elev. 86. The soils- below this elevation are very stiff to hard clay/dense silt. Based on the information provided. to us, it appears. that the- major, portion of the.excavation for Building 5 will expose granular silty sand soils. Temporary excavations sloped to an inclination of 1.5:1 will encroach very near the cePterline of the proposed loop road . located immediately south of the building, and would extend about five feet over the centerline near the southwestern' comer of the building. We understand that there. will be some flexibility With' excavating into' the 'loop *road during site development-, however,* if encroachments into the proposed roadway -of this magnitude cannot be tolerated, temporary shoring will be needed. The excavation for Building 8 is likely to.encounter- minor groundwater' seepage at various levels below 8.5 feet. Considering the fine-grained. nature of the on -site soils, we'do not believe the amount of seepage will be excessive. In.addition, if adequately pro . tected from erosion, we do not expect that seepage will adversely affect the stability (if the temporary slope. However, the contractor should be prepared to provide, dewatering measures for. the excavation. In our opinion, conventional sump -pumping procedures should be capable of maintaining 6 relatively dry condition for the excavation. Ten�porary shoring will be required where site .constraints do not allow sloping of temporary excavations to the inclinations discussed above. Temporary 'shoring systems include. a tied -back or cantilever soldier.pile wall and soil nailing wi ' th top -down wall construction. Considering the presence of as much a's 13 feet of loose,'uncontrolled fill nearthe southwestern comer of Building 4, and the proximity to a'public right-of-way, it is our opinion that temporary shoring should consist of a tied -back or cantilever soldier pile wall. Descriptions of the shoring method and detailed design parameters are presented below. The follo, -wing sections provide detailed recommendations regarding these issues and other geotechnical design. -co fisideratidns. These recommendations should be incorporated into the final design drawings and construction-s'pecifications. .Shoring As discussed, te or shoring will bere'quired where there is insufficient roomto complete an open Mp ary excavation to the inclinations discussed. in. the. preceding section. Ove­rconsolidated clay/silt Will be encountered below the'fil.1 znd granular native soils. During the excavation, soil expansion resulting froin'relea.se of Iocked-in stresses combined with horizontal planeslacking cohesion, may cause hotizontal slippage,at a- newly opened excavation; - Based on our.expenence,.the -newly opened. vertical 'face should not be left open more. -than 48 hours. Timber lagging -should -be installed within. 48 hours to pfevent.hbriwntal slippage-.. Detailed recomniendations for conventional -soldier pile walls with timber lagging are ov'ded below. PT .-Pr eci No. T-4893 Oi age No. 4 Mr. Ross Wood.9- July 30, 2003 Soldier Pile Shoring Tied -back or cantilever soldier walls should. be designed. to resist lateral loads imposed by soils, as well. as the vertical load component. Vertical loads may- be carried by the soldier piles as end bearing and as pile shaft friction below the base* of the excavation. P116 shaft friction' should not be used above the base of the excavation., The following information is appli cable to soldier pile walls: Bearing materials: hard lean clay Minimum depth of embedment below excavation base: 10 -feet Allowable. end bearing capacities for. soldier piles: 20 kips per square foot (ksf) Skin friction below' excavation base:, 1.0 ksf We recommend soldier piles have a maximum centef-to-center spacing of eight feet. To account for arching effects, lateral loads. on the lagging can be. reduced by 50 percent. Design parameters'for the recommended temporary shoring are presented onFigures. 12 and 13. Tieback Anchors Tieback anchors should* be installed in the soil behind the excavation to a sufficient distance to allow mobilizinL- the. desired- lateral load resistance. The soils in the anchor zone are expected to consist of very stiff to -hard lean. clay. We recommend the use of the following design adhesion values for properly installing non -pressure grouted anchors. Allowable Adhesion:, LOksf, along the bonded length The -bonded length is the portion of the anchor that extends beyond- the no-load zone,' as shown- on P Figure- 14. Within the no-load zone, anchors,. should be sleeved - and left u'ngrouted, to prevent load pickup in this region. All anchors should be test6d to verify design ca' a p cities.. As'a minimunij all anchors should bi,, -stressed to 130 percent of their design capacity and.thenIocked off at the design load. At least 10 percentof the anchors, with a minimum- of 2 anchors, should be prooftested and stressed to 200, percent of -the design pullout capacity.* The geoiechnicaLengineer shl6uld select thel.ocations of these test anchors. Groundwater seepage may' -be �ericountered, during the,installation*of the anchors, The'presence of water could result in so - me caving.of the anchor . holes.- Drilling, with continuous flight augers or. the use of ...casing Would reduce thepotential for ground loss.. The contractor should par ticularly..riote. the pres ence of existing facilities adjacent to the subject site, including buried utilities, as they -may. affect the location or extent of the anchor holes., Project No T-4893 Page.No. 5 I Mr-R-oss Woodg- July 30, 2003 Monitoring Program A monitoring'program. must be implemented to verify the performance of the shoring system.'Utilities within a distance of. 1.0 H. (where H is the depth of excavation), from the shoring wall' should be protected ftoni damage du e* to the lateral and vertical, movernent occurring around the excavation 'area. Monitoring of the shoring system should include measurements of horizontal and vertical movements at the t . op of soldier piles. -All reference points on the existing ground surface should be installed -and read prior to commencing the excavation. Monitoring of the shoring system should be performed twice a week as the excavation proceeds,. And then �every other week upon completion of the excavation. A registered land surveyor should be retained to perform the monitoring. Monitoring should continue until the basement walls are adequately braced at the ground surface -level. The-,moniltoring data should be reviewed weekly by the project's structural and geotechnical engineers. All recommendations presented in our earlier report should. also be incorporated into project design and construction. We trust the inf6rmati6n presented is- sufficient for your current needs. If you have any questions or require additional information, please call. Sincerely yours, TERRA ASSOCIATES, INC. John Ahil -PE-17005, Ge tec ,T.A*/JCS/AB:a 1219/0 _j Enc ---ri r oration Location,irian.s Unif Figure 3 i6d Soil Classification System Figures 4 through 9 — Boring and Test Pit Logs Figures 10 and 11.7- Grain Size Analyses Figure 12 — Eafth -pressure Diagram, 0 .EV. 111.61 J) 7—_ BLDG 1 APPROXIMATE PERIMETER 77­ OF LOWER LEVEL LOWER LEVEL ELEV./Z4.67 ...... ........ BLDG. 4 LOWER LEVEL ELEV. 100.66 TP- V\ c 94 0A,\ till APPROXIMATE PERIMETER OF LOWER LEVEL BLDG 3 -,'-LOWER LEVEL ELEV. 101.17 TP-1 -101 BLDG 10m. \'L6wg LEVEL ELEV. 134.84\ cp W -L 2�_ :7. 77 (*4 NOTE: THIS SITE PLAN IS SCHEMATIC. ALL LOCATIONS AND DIMENSIONS ARE AOPROXIMATE.,IT IS INTENDED FOR REFERENCE ONLY AND'SHOULD NOT BE USED FOR DESIGN OR CONSTRUCTION PURPOSES. REFERENCE:. SITE PLAN PROVIDED BY TRIAD ASSOCIATES, DATED 7-21-03 LEGEND: 134 APPROXIMATE LOCATION OF.BORING.' fflTP-1 APPROXIMATE LOCATION OF TEST PIT 0 50 lob PE ;0111111111111�� APPROXIMATE, SCALE IN FEET z M MR m MM... -0 ;a ;o '-- 17 F, m z MLA j Z, W-1 u —u ;v Oz -a 0 rn ;G 0 zm z t < CO r- M 0 > %It c Z-u I 0 om 0 XX > -N, z > 0 > m 711. k (1) -O'z � F- k k U) -0 0-4 r- 0. C41) --4 - rj) rn W. 0 0 !11 m-z 0 1 > I C # M ch M nm U) §! 0 M 0 > ;D'Tl Z ro- I r r r m r Im cn Co 1 11, v k M I F" m if V\ 1 -41 A > "U "a t ;o X L t M, 0 0 0 0 z > q M 0 0 r 0 z z 177-r7, 0 0. S X/ ZS -n "n IIII oo, rn rd Cl) CO irri .0 U/ 22 Q jw ;D "n 'a) rn— Z' P4 r tj I I I k k, M r1i r m N�' /* \V 0> M-W All M m r— M 0 ;X Mw 0 /0 ;19 0 m X mz, F— /m 0M.O. r r 14 OM V6 Ax z > r 0 > 9 cn;o 0 a z r-mT m C/) r-� m V /rm C) U cn 0 0, Vibf. j 11f 89Z 7! ZZ-0 IV F. z it MAJOR DIVISIONS LETTER TYPICAL DESCRIPTION SYMBOL Clean GW Well -graded gravels, gravel -sand mixtures, little or no GRAVELS Gravels fines. GP Poorly -graded gravels, gravel -sand mixtures, little or U) _j a (less than 0 -T N More than 5% fines) no fines. GM Silty gravels, gravel -sand -silt mixtures, non -plastic U) 50% of coarse a) a) > fraction is larger than No. Gravels fines. GC clayey gravels, gravel -sand -clay mixtures, plastic fines. W a) z CU E 4 sieve with fines (D C) Clean SW Well -graded sands, gravelly sands, little or no fines. LO SANDS Sands SP Poorly -graded sands or. gravelly sands, little or no W C Z U) CU (less than ix I= C More than 5% fines) fines. < CU a) 50% of coarse 0 L_ � 0 fraction is SM Silty sands, sand -silt mixtures, non -plastic fines. 0 smaller than Sands SC Clayey sands, sand -clay mixtures, plastic'fines. No. 4 sieve with fines ML Inorganic silts, rock flour, clayey silts with slight U) _j LD C) L_ SILTS AND CLAYS plasticity. CL Inorganic clays of low to medium plasticity, (lean clay). a) C) CU N U) E 6 Liquid limit is less than 50% 0 W �z N OL Organic silts and organic clays of low plasticity. C:) r- Z LO M < .0 > C �' a) MH Inorganic silts, elastic. 0 CU = �) (n — SILTS AND CLAYS = 2 co CH Inorganic clays of high plasticity, fat clays. W E z 0 Cn 2 Liquid limit is greater than 50% LL OH Organic clays of high plasticity. HIG HLY ORGANIC SOILS PT Peat. DEFINITION OF TERMS AND SYMBOLS Standard, Penetration Density Resistance in Blows/Foot 2" OUTSIDE DIAMETER SPLIT SPOON SAMPLER W z 0 Very loose 0-4 2.4" INSIDE DIAMETER RING SAMPLER U) Loose 4-10 -OR SHELBY TUBE SAMPLER W 1: Medium dense 10-30 Dense 30-50 WATER LEVEL.(DATE) 0 Very dense >50 Tr TORVANE READINGS, tsf PP PENETROMETER READING, tsf Standard Penetration Consistenc Resistance in Blows/Fo ot DD DRY DENSI pounds per cubic foot ITY, W CD Very soft 0-2 LL. LIQUID LIMIT, percent W Soft 2-4 T Medium stiff 4-8 P1 PLASTIC INDEX 0 stiff 8-16 Very stiff 16-32 N STANDARD PENETRATION, blows per foot Hard >32 UNIFIED $OIL. CLASSIFICATION SYSTEM EioTerra Associates,. Inc. POINT EDWARDS CONDOMINIUMS . EDMONDS, WASHINGTON Consultants in Geotechnical Engineering Proj., No. T-4893 Date"JULY 2003 Figure 3 Geology and Envkonm6ntal Earth Sciences Boring No. B-101 Logged by: TA Date: 6/18/03 Approximate- Elev. 105 Soil Description Consistency/ Relative Depth -a E (N Blows/ Moisture Content Density M ft. N FILL: dark brown silty sand with gravel, moist. (SM) Dense T 30 10 Brown silty SAND, trace gravel, with oxidized stained, moist. (SM) Brown mottled gray between 2.5 to 4.0 feet. Medium Dense 5 17 11 12 15 Gray, lean -CLAY, trace subrounded gravel, moist. (CL) 7 20 _10. Medium - 22 27 stiff to Occasional light gray silt seams below 15 feet. Hard —15 —20 - 35 44 26 25 Gray silty SAND, wet. (SM) Dense Gray, lean CLAY -with light gray SILT seams. Hard 25 32 .29 .Boring terminated at 26.5 feet. Groundwater'seepage encountered at 21 feet. Terra, BORING. -LOG Assodates, l.nc.., POINT EDWARDS' CON DOMIN I LIMS EDMONDS, WASHINGTOW Cons6itants In Geotechnical Engineering Oeology-and EnVironmental'.Earth sciences Prof. No., T-4893 Date JULY 20,03 Figure 4. �2 Boring No. B-102 Loggpd by:.TA Date: 6/ . 18/03 Approximate Elev. 125 Soil Description Consistency/ Relative Density Depth E U) (N)_ Blows/ ft. Moistu re Content - N 15 19 FILL: brown silty sand, trace gravel/clayey silt, moist. (SM/ML) Medium Dense to Very Loose 10 13 9 3 24 5 7 11 1.0. 23 _T Gray, lean CLAY, occasional light gray silt and sandy silt seams (11 to 2 mm), moist. (CL) 20 22 31 0.5 inches light gray sandy silt seam at 26 feet. Very stiff 29 36 0.5 inches sand seam at 30.5 feet. 30 33 26 29 27 —407 38 25 Gray SAND with silt, free water. (SM) Dense Gray, lean.CLAY, moist. (CL) T 37' 27 50- 32 25 Boring terminated at 51.5 feet. Groundwater encountered at 40 feet. Terra BORING:LOG Associates, Inc. Consultants in Geotechnical Engineering Geology and Environmental Earth Sciences POINT EDWARDS CONDOMINIUMS EDMONDS, WASHINGTON Pr6j. No. T-490 I Date -JULY 20031' 'Figure 5. 156 Boring No. B-103 Logged by- TA Date: 6/18/03 Approximate Elev. 1.29 Soil Description Consistency/ Relative Density D ' epth (ft.) E (N) Blows/ ft. Moisture Content Notes CRUSHED GRAVEL Dense 5 36 15 2 17 28 FILL: dark gray clayey SILT/sifty SAND, trace gravel, moist. (MUSM) Medium Dense Brown silty SAND to SAND with silt, free water. (SM) Medium Dense - - _710 16 22 24 36 'Gray lean CLAY, moist. (CL) Brown lean CLAY with oxidized stained between 15.0 to .15.5 feet. Very —15 - 31 28 ............. ............ ...... Wet soils encountered at 21.5 feet. stiff to - —20 T 30 24 ...... ..... .............. Hard Occasional light gray silt and silty sand seams encountered below 25 feet. 25 28 32 ............. .......... ............. ...... ...... ...... . . . 4 inches sand seam at 31 feet. 35 23 ............. ............. —35 4.1 29 ............ ...... ........ Boring terminated at 36.5 feet. Groundwater seepage encountered at 8.5 feet. Water level at 22.15 feet on June 19, 2003*.. Terra BORING'LOG Associates,. I n1c PGINT,EDWARDS -CONDOMINIUMS EDMONDS, WASHINGTON Consultants in Geotechnical Engineering Geology and Environmental Earth Sciences Proj. No -------------- J-489 Date JULY 2003 Figu Boring No. B-4 Logged by: DPL Date: 12/16/02 Approximate Elev. 90 Soil. Description Consistency/ Relative Depth E (N) Blows/ Moisture Content Density 10 U) ft. FILL (Old test pit): bluish -gray silty sand, fine grained, Loose wet, with a trace of wood particles. Appears disturbed. :E 7 27 FILL (Old test pit): mottled brown silty sand, fine grained, moist. Medium Dense 10 - 17 21 31 FILL (Old test pit): brown silt and clay, moist, with a trace ----of brown organic -material -------------------------------------------------- Very Stiff ----------- Bluish -gray SILT to CLAY, low to medium plasticity. Very V 28 (MUCL) stiff Gray SILT to CLAY, moist, low to medium plasticity. (MUCL) ------------------------------------------------------------ ------------ Very Stiff ------------------------- —20 30 23 LL = 35.5 PI = 11.5 Grayish-brown sandy SILT to clayey SILT, fine grained, moist. (ML) With thin partings of iron -stained, fine-grained Very stiff 35 23 sand. Grayish -brown clayey SILT to silty CLAY, moist. (MUCL) With thin discontinuous lenses of gray to mottled gray .___finf�-_q!ained -sand -------------------------- I ------------------------------------------------- Very stiff —30 30 24 Gray silty SAND, fine grained, moist. (SM) Dense 37 15 ---------------------------------------------------- --------------------- Gray sandy SILT to clayey SILT, fine grained, moist, low plasticity. (ML to MUCL) -------------------------- Hard —40 _F 34 17 Gray cl - ayey SILT, moist, low plasticity. (ML/CL). sand Hard 37 20 Gray sandy SILT to silty SAND, fine grained', moist, Dense 50 32 19, (MUSM) 47 18 —60 :L 42 15 Boring terminated at 61.5 feet. No significant groundwater encountered. Terra BORING LOG POINT EDWARDS CONDOMINIUMS EDMONDS, WASHINGTON Consultants in Geotechnical Engineering Geology and Environmental Earth sciences Prqj. No. T-4893 FQate. J U LY� 20031 Figure. 7 Test P.it No. TP-1 Logged by: JCS Approximate Elev. 104 Date: 10/18/01 Moisture Depth Content Soil Description M4 (%) 0 5t 10 15 .20 Test Pit No. TP-2 Logged by: JCS Approximate Elew 124 Date: 10/18/01 Moisture Depth Content: Soil Description (%) FILL: crushed rock surfacing over brown to gray silty sand to sandy silt, fine grained, firm, moist.,( M/ML) Rusty brown silty SAND fine grained; medium dense, moist, with occasional fine \gravel and fine roots. (9M) Gray to moftled gray silty SAND, fine grained, medium dense to dense, moist, with occasional fine gravel. (SM) Becomes light brown at approximately feet. Gray CLAY, hard, moist, massive. (CL) 26 PP 4.5+ tons/fe: ILL 35.8 PI 15 — Test pit terminated at 14 feeL 7 No groundwater seepage. FILL: crushed rock surfacing over brown silty sand to sandy silt, fine grained, firm, moist. 4-inch thick organic layer at base. (SM/ML) (Old psoil horizon). Brown silty SAND, fine grained, medium dense, moist. (SM) Mottled grayish -brown, silty SAND, fine grained, medium dense, moist. 20 (SM) Grayish -brown silty SAND, fine grained, medium dense to dense, moist (SM) iS�ray CLAY, hard, moist, laminated with light graysilt partings. �(CQ PP 4.5+ tonslft' 37 Test pit terminated at 14 feet. No"grouridwater seepage. TEST PIT LOGS+ -Terr-a POINT EDWARDS CONDOMINIUMS EDMONDS, _WASHINGTON'. Agsociate's, Inc. - Geotechnical Consultants Pfoj. No.'T-480 - Date JULY 20031 Figurd 8 Logged by: JCS Date: 10/18/01 Dep th 0— FILL: light brown silty sand -inch thick 016 fine grained, firm, dry to moist. (SIVI) 2 organic layer at base. ( topsoil horizon) Light brown to tan silty SAND, fine grained, medium dense to dense, dry. ($M) Mottled grayish -brown silty SAND, fine grained, medium dense to dense, 29 5— moist. (SM) ILL = 42.7 Light grayish -brown to light brown CLAY and SILT, hard, moist, laminated 29 PI = 19.7 with partings of dark gray fine sand. (CUML) PP = 4.5+ tons/ft' 10— 'Gray CLAY, hard, moist. (CL) 29. PP = 4.5+ tons/fe Test pit terminated at 13 feet. 15— Trace groundwater seepage at 6 feet. 7 20— Test Pit No. TP-4 Approximate Elev. 92 Moisture Soil Description Content TEST- PIT LOGS ­ Terra POINT EDWARDS CONDOMINIUMS EDMONDS, WASHINGTON Associates, Inc. Geotechnical Consultants PrQj. NO. T-4893 Date;J.ULY2003*. Figure 9 CANTILEVER SOLDIER PILE WALL OR SINGLE- ROW TIEBACK WALL H >`-D �\-' I I , I I r Pass I ve Earth Pressure = 400 pcf taken over 2 pile diameters Note: Value includes Safety Factor of 1.5. D 40* pcf 75 psf Traffic Surcharge Where Applicable 40(H)* psf taken over pile diameter NOT TO SCALE INCREASE PRESSURE BY 20 PERCE-UT--WHER�..WALL IS SURCHARGED BY BACKSLQPE OF' 2:1 (HORIZONTALMERTICAL) OR' FLATTER. Terra ..EARTH PRESSURE DIAGRAM POIrNTEDWARDS CONDOMINIUMS Associates, Inc.. E.DMONDS, WASHINGTON Consult6rits in" Geotechniic�l Endiqe�ering Geology.and P.roj..�Jo: T-4893 Dat6 I JULY.200.3 Figur . el 2 Environmental Earth Sciences: SOLDIER PILE WALL WITH TWO OR MORE TIEBACKS 0. 2 (H) 15' 75 psf UNIFORM PRESSURE TRAFFIC SURCHARGE WHERE H, APPLICABLE 23 (H)* psf APPLIED OVER, PILE SPACING '2' 400 pcf/ft.PASSIVE EARTH, PRESSURE. APPLIED OVER 2(D) 23 (H)* psf APPLIED OVER PILE DIAMETER NOTE: VALUE INCLUDES SAFETY FACTOR OF 1.5 11 AII- D NOT TO SCALE INCREASE PRESSURE BY 26 (H) WHERE WALL IS -SURCHARGED �BY BACKSLOPE OF 2:,l (HORlzbNTAL:.VERTICAL) OR FLATTER. Terra, EARTH PRESSURE DIA.GRAM, POINT EDWARDS CONDOMINIUMS Asso'ciat6s,- Inc. EDIVIONDS,WASHINGTON Consultants in. Geotechnical. Engineering and, Proj. . No. T-489 3 D6te JULY 2003 rel EnVironmental Earth Sdiences H TIEDBACK SOLDIER PILE/LAGGING SHORING WALL , - , - -, , I NO LOAD ZONE 5- (TYPICAL) ANCHOR ZONE TIEBACKS NOT GROUTED rz IN THIS ZONE TIEBACKS GROUTED IN THIS ZONE H/3 60 ALLOWABLE, TIEBACK ADHESION CAPACITY IN ANCHOR ZONE=1000 psf NOTE: Al it TIEBACK CAPACITIES ARE BASE. ON INSTALLATION USING TREMIE GROUT METHOD NOT TO SCALE I RA LOAD/NO LOAD ZONEb'AG Terra. POINT EDWARDS CONDOM IN I.QMS. As�sociates, Inc. EDMONDS, WASHINGTON ConWtants in Geotechnical Engineering GeV' and -4893. Envir6 , -Earth Se'lences". r0i n entaf P '.No. T Date JULY.20.03. Figpre 14 16 EARTH PRESSURE DIAGRAM FOR BASEMENT WALLS. EXTERIOR GRADE /1,7 ............. ......... ..... 0.2(H) TRAFFIC 15' SURCHARGE ACTIVE WHERE H PRESSURE APPLICABLE 23(H)* psf + 75 psf . 4 NOT TO SCALE *INCREASE PRESSURE TO 26 (H) WHERE WALL.IS SURCHARGED. BY BACKSLOPE OF 2:1 (H ORIZONTAL:VERTI CAL) OR FLATTER. Tetra EARTH PRESSURE DIAGRAM -BASEMENT WALLS POINT EDWARDS CONDOMINIUMS Ats okiates, In'.c. EDMONDS, WASHINGTON 'Consuit4nts in 66ote�hnical Engineering Geolo 6mengy -4 9 ta� and Enviro Earth Sciences Proj.. No'.T 8 3 Date J U LY 2003 :,F gure 15 TERRA ASSOCIATES, Inc. Consultants in Geotechnical Engineering, Geology and Environmental Earth Sciences July 30, 2003 Project No. T-4893 Mr. Ross Woods RESUB Point Edwards, LLC 2801 Alaskan Way, Suite 107 SEP - 6 7005 Seattle, Washington 98121 SUILDING DEPARTMEN1 Subject: Supplementary Subsurface Exploration cyTy OF EDMONDS Point Edwards Condominiums Pine Street and Unoco Road Edmonds, Washington References: 1. Geologically Hazardous Areas Review, Point Edwards Condominiums (UNOCAL Site), prepared by Terra Associates, Inc., dated January 20, 2003 2. Preliminary Geotechnical Report, UNOCAL Site, Project No. T-4893, prepared by Terra Associates, Inc., dated November 21, 2001 Dear Mr. Woods: As requested, we have completed supplementary subsurface exploration at the subject site. The purpose of our study is to evaluate the need for temporary shoring during construction of the proposed buildings, and to provide recommendations for temporary shoring design and construction where needed. We previously performed geotechnical studies for the project and presented our findings in the referenced reports; however, since that time, building locations and site grading have been refined. Tria'd Associates provided us with a current topographic site plan dated July 21, 2003 that shows existing topography and proposed site grading. .Our current study focused on areas where significant site excavations will be required adjacent the. downgradient (northern) side of Pine Street, in the areas of Buildings 3, 4, and 8, and the area of Building 5, located north of Building 8 and the private loop road. Pine Street is currently one of two roadways that access the community of Woodway, south of the site. This report summarizes the results of our recent subsurface exploration and discusses supplementary shoring recommendations for the project. BEET FILE 12525 Willows Road, Suite 101, Kirkland, Washington 98034 Phone (425) 821-7777 a Fax (425) 821-4334 * terra@terra-associates.com Mr. Ross Woods July 30, 2003 PROJECT DESCRIPTION The project will consist of the construction of ten condominium buildings. The proposed structures will be three to four stories with daylight basements and one to two levels of underground parking. We expect that perimeter load-beaning walls and isolated spread footing loads will be as indicated in the referenced report. The excavation depths required for construction of the lower parking levels will approach a maximum of about 27 feet below existing grades along Pine Street. The recommendations contained in the following sections of this report are based on our understanding of the above design features. If actual features vary or changes are made, we should review them in order to modify our recommendations, as required. We should review final design drawings and specifications to verify that our recommendations have been properly interpreted and incorporated into project design. SUBSURFACE CONDITIONS We previously investigated subsurface conditions at the site by excavating 17 test pits (Test Pits TP-1 through TP- 17) and drilling 5 test borings (Borings B- I through B-5). Our current exploration -included drilling three additional test borings (Bonings B-101 through B-103) on June 18, 2003. The recent borings were drilled on the north side of Pine Street, where significant excavations will be required for construction of the lower'parking levels of Buildings 3, 4, and 8. These test bonings were advanced to a maximum depth of approximately 51.5 feet below the ground surface. The approximate locations of the recent test borings, and nearby test pits/test borings from our previous studies, are shown on Figures I and 2. The boring logs and test pit logs are shown on Figures 4 through 9. We performed grain size analyses on. three representative soil samples obtained from the test borings. The test results are presented on Figures 10 and 11. The soils encountered in Bonings B-101, B-102, and B-103 consist of 1 to 13 feet of very loose to medium dense uncontrolled fill overlying medium dense, native silty sand with varying amounts of gravel to depths between approximately 7 and 13 feet below the ground surface. The fill and silty sand soils are underlain by very stiff to hard, lean clay with thin partings of light gray silt and/or very fine- grained silty sand seams to the maximum exploration depths of the borings. These soil conditions are generally consistent with the soils we observed in nearby test pits. The Geologic Map of the Edmonds East and Part of the Edmonds West Quadrangles, Washington by James P. Minard, 1983, shows the soils at higher site elevations mapped as Vashon till, Vashon advance outwash, and Transitional beds. Transitional bed sediments are described by this publication as massive to bedded clay, silt, and fine to very fine sand. T he clay and silt soils observed at depth 'in the test pits and encountered in the test borings are generally consistent with the descriptions of transitional bed deposits. Project No. T-4893 Page No. 2 Mr. Ross Woods July 30, 2003 We encountered perched groundwater in all three of the recent borings near the interface of the surficial fill/silty sand soils and the underlying very stiff to hard clay, and in thin sand layers within the very stiff to hard clay. We also observed indications of localized light seepage from the face of the existing slope between proposed Buildings 4 and 8. The perched groundwater encountered in Borings B-101 and B-102 occurs at elevations at least 15 feet below the lower elevations of Buildings 3 and 4 (Elev. 10 1. 17 and Elev. 100.66, respectively). Boring B-103 (drilled in the area of Building 8) encountered,two levels of perched groundwater. The upper perched groundwater level is approximately 8.5 feet below the ground surface (approximately Elev. 120.5), and the lower level is approximately 22 feet below the ground surface (approximately Elev. 107). The proposed elevation of the lower level for Building 8 is Elev. 111.67. Fluctuations in groundwater seepage levels should be expected on a seasonal and annual basis. Typically, groundwater seepage reaches maximum levels during and following the wet winter months, and diminishes or is completely absent during the dry summer months. We did not observe groundwater seepage in Test Pits TP-1 and TP-2 (located in the areas of Borings B-101 and B-102, respectively), which were excavated to a depth of about 14 feet in mid -October 200 1. DISCUSSION Based on our review of existing topography, proposed grades, and the planned building elevations, it appears that temporary shoring will be required to complete the southwestern portion of the excavation for Building 4. Soils encountered in Boring B-102, in the southwestern portion of Building 4, consist of approximately 13 feet of very loose to medium dense fill and medium dense native. silty sand overlying very stiff to hard clay. As discussed in our referenced geotechnical report, the loose to medium dense fill and native silty sand soils should be laid back at a minimum slope inclination of 1.5: 1 (Horizontal:Vertical). Temporary slopes in the very stiff to har d clay can be completed with a gradient of 0.75: 1. Based on the depths that we encountered these soils -in Boring B-102, excavations completed to these temporary inclinations at the southwestern comer of Building 4 would encroach about 40 feet into the Pine Street right-of-way and about 16 feet into the existing paved roadway. Excavation to the proposed lower floor elevation in the southwestem portion of Building 3 will expose primarily medium dense silty sand with varying amounts of gravel. Temporary excavations in these soils that are graded to an inclination of 1.5:1 will extend about 27 feet into the Pine Street right-of-way at the southwestem comer of the building, but would not encroach into the existing roadway. The soils in the area of Building 8 consist of existing fill, native silty sand, and very stiff clay/dense silt. Based on the information provided to us, it appears that temporary excavations for Building 8 that are sloped to an inclination of 1.5:1 will not encroach into the Pine Street right-of-way. We expect that the lower portion of the excavation for Building 8 will exposed very stiff clay/dense silt, and may be graded to a temporary inclination of 0.75: 1. Project No. T-4893 Page No. 3 Mr. Ross Woods July 30, 2003 Subsurface information obtained from our previous geotechnical studies indicates that the soils near the western side of Building 5 consist of existing fill and native, medium dense silty sand to approximately Elev. 86. The soils below this elevation are very stiff to hard clay/dense silt. Based on the information provided to us, it appears that the major portion of the excavation for Building 5 will expose granular silty sand soils. Temporary excavations sloped to an inclination of 1.5:1 will encroach very near the centerline of the proposed loop road located immediately south of the building, and would extend about five feet over the centerline near the southwestem. comer of the building. We understand that there will be some flexibility with excavating into the loop road during site development; however, if encroachments into the proposed roadway of this magnitude cannot be tolerated, temporary shoring will be needed. The excavation for Building 8 is likely to encounter minor groundwater seepage at various levels below 8.5 feet. Considering the fine-grained nature of the on -site soils, we do not believe the amount of seepage will be excessive. In addition, if adequately protected from erosion, we do not expect that seepage will adversely affect the stability of the temporary slope. However, the contractor should be prepared to provide dewatering measures for the excavation. In our opinion, conventional sump pumping procedures should be capable of maintaining a relatively dry condition for the excavation. Temporary shoring will be required where site constraints do not allow sloping of temporary excavations to the inclinations discussed above. Temporary shoring systems include a tied -back or cantilever soldier pile wall and soil nailing with top -down wall construction. Considering the presence of as much as 13 feet of loose, uncontrolled fill near the southwestem comer of Building 4, and the proximity to a public right-of-way, it is our opinion that temporary shoning should consist of a tied-ba * ck or cantilever soldier pile wall. Descriptions of the shoring method and detailed design parameters are presented below. The following sections provide detailed recommendations regarding these issues and other geotechnical design considerations. These recommendations should be incorporated into the final design drawings and construction specifications. Shoring As discussed, terTiporary shoring will be required where there is insufficient room to complete an open excavation to the inclinations discussed *in the preceding section. Overconsolidated clay/silt will be encountered below the fill and granular native soils. During the excavation, soil expansion resulting from release of locked -in stresses combined with horizontal planes lacking cohesion may cause horizontal slippage at a newly opened excavation. - Based on our experience, the newly opened vertical face should not be left open more than 48 hours. Timber tagging should be installed within 48 hours to prevent horizontal slippage. Detailed recommendations for conventional soldier pile walls with timber lagging are provided below. Project No. T-4893 Page No. 4 Mr. Ross Woods July 30, 2003 Soldier Pile Shoring Tied -back or cantilever soldier walls should be designed to resist lateral loads imposed by soils, as well as the vertical load component. Vertical loads may be carried by the soldier piles as end bearing and as pile shaft friction below the base of the excavation. Pile shaft friction should not be used above the base of the excavation. The following information is applicable to soldier pile walls: Bearing materials: Minimum depth of embedment below excavation base: Allowable end bearing.capacities f6r soldier piles Skin friction below excavation base: hard lean clay 10 feet 20 kips per square foot (kso 1.0 ksf We recommend soldier piles have a maximum center -to -center spacing of eight feet. To account for arching effects, lateral loads on the tagging can be reduced by 50 percent. Design parameters for the recommended temporary shoring are presented on Figures 12 and 13. Tieback Anchors Tieback anchors should be installed 'in the soil behind the excavation to a sufficient distance to allow mobilizing the desired lateral load resistance. The soils in the anchor zone are expected to consist of very stiff to hard lean clay. We recommend the use of the following design adhesion values for properly installing non -pressure grouted anchors. Allowable Adhesion: 1.0 ksf, along the bonded length The bonded length is the portion of the anchor that extends beyond the no-load zone, as shown on Figure 14. Within the no-load zone, anchors should be sleeved and left ungrouted to prevent load pickup 'in this region. All anchors should be tested to verify design capacities. As a minimum, all anchors should be stressed to 130 percent of their design capacity and then locked off at the design load. At least 10 percent of the anchors, with a minimum of 2 anchors, should be prooftested and stressed to 200 percent of the design pullout capacity. The geotechnical engineer should select the locations of these test anchors. Groundwater seepage may be encountered during the installation of the anchors. The presence of water could result in some caving of the anchor holes. Drilling with continuous flight augers or the use of casing would reduce the potential for ground loss. The contractor should particularly note the presence of existing facilities adjacent to the subject site, including buried utilities, as they may affect the location or extent of the anchor holes. Project No. T-4893 Page No. 5 Mr. Ross Woods July 30, 2003 Monitoring Program A monitoring program must be implemented to verify the performance of the shoring system. Utilities within a distance of 1.0 H (where H is the depth of excavation) from the shoring wall should be protected from damage due to the lateral and vertical movement occurring around the excavation area. Monitoring of the shoring system should include measurements of horizontal and vertical movements at the top of soldier piles. All reference points on the existing ground surface should be installed and read prior to commencing the excavation. Monitoring of the shoring system should be performed twice a week as the excavation proceeds, and then every other week upon completion.of the excavation. A registered land surveyor should be retained to perform the monitoring. Monitoring should continue until the basement walls are adequately braced at the ground surface level. The monitoring data should be reviewed weekly by the project's structural and geotechnical engineers. All recommendations presented in our earlier report should also be incorporated into project design and construction. We trust the information presented is sufficient for your current needs. If you have any questions or require additional information, please call. Sincerely yours, I ana 2 - Exploration Location Plans Figure 3 — Unified Soil Classification System Figures 4 through 9 — Boring and Test Pit Logs Figures 10 and I I — Grain Size Analyses Figure 12 — Earth Pressure Diagram Figure 13 — Earth Pressure Diagram Figure 14 — Load/No Load Zone Diagram Figure 15 — Earth Pressure Diagram -Basement Walls cc: Ms. Beth Jensen, DO Engineers Project No. T-4893 Page No. 6 .EV. 111.61 BLDG 1 APPROXIMATE PERIMET ER OF LOWER LEVEL -LOWER LEVEL ELEV/:!�.67 F7. BLDG. 4 .......... LOWER LEVEL ELEV. 100.66 V Nl� N N, kill' I01 ....... k APPROXIMATE PERIMETER OF LOWER LEVEL N. bLUU J L LOWER LEVEL ELEV. 101.17 -101 TP 1 Y, BLDG 10E -LOWE LEVEL ELEV. 134.84 -vs- Al A -7 7- w: NOTE: : LEGEND: THIS SITE PLAN IS SCHEMATIC. ALL LOCATIONS AND DIMENSIONS ARE APPROXIMATE. IT IS INTENDED FOR B-1 APPROXIMATE LOCATION OF BORING REFERENCE ONLY AND SHOULD NOT BE USED FOR DESIGN OR CONSTRUCTION PURPOSES. MTP-1 APPROXIMATE LOCATION OF TEST PIT. Terra 0 50 .100 Associates Inc. REFERENCE: Consultants in Geotechnical Ingineering SITE PLAN PROVIDED BY TRIAD ASSOCIATES, DATED 7-21-03 APPROXIMATE SCALE IN FEET Geology and Environmental Earth Sciences EXPLORATION LOCATION PLAN POINT EDWARDS CONDOMINIUMS EDMONDS, WASHINGTON Proj. No. T-48931 Date JULY1200 4_� �__ z Of- 777� ;07 - - - - - - - - - - - - - - - - - - - --- �_J_ Am TP-1 B-4 - ----------- 'AOPROXIMATE PERIM TER j------ ------ OF LOWER LEVEL BLDG. 5 ------- ---------- '------LOWER LEVEL _ELEV. 82.17 7 - - - - - - - - - - - - \PLW 2\ LOWER LEVEL ELEV.'74.66 APPROXIMATE PERIMETER OF LOWER LEVEL. Z N 0, 7-7- BLDG. 8 /* -LOWER LEVEL ELEV. 1 11.6f. Z:� N, —B-10 APPROXIMATE PERIMETER OF LOWER LEVEL-' BLDG�4 ....... LOWER LEVEL ELEV. 100.66 TP�2 BA 02 0 NOTE: LEGEND- -THIS SITE PLAN IS SCHEMATIC. ALL LOCATIONS AND DIMENSIONS ARE APPROXIMATE. IT IS INTENDED FOR 19 B-1 APPROXIMATE LocA-nON OF TEST BORING EXPLORATIONLOCATION PLAN REFERENCE ONLY AND SHOULD NOT BE USED.FOR Terra DESIGN OR CONSTRUCTION, PURPOSES. 19 TP-1 APPROXIMATE LOCATION OF TEST PIT POINT EDWARDS CONDOMINIUMS Associates Inc. EDMONDS, WASHINGTON REFERENCE: 0 �0 100 Consuftants'.In Geotechnical Ingineering Geology and -48o 0 Figure 2 SITE PLAN PROVIDED BY T RIAD ASSOCIATES, DAED 7-21-03 APPROXIMATE SCALE IN FEET.. Environmental Earth Sciences .Proj. No. T Date JULY 2 03 F MAJOR DIVISIONS LETTER SYMBOL TYPICAL DESCRIPTION Clean GW Well -graded gravels, gravel -sand mixtures, little or no GRAVELS Gravels fines. GP Poorly -graded gravels, gravel -sand mixtures, little or W (U 0) " (less than a) 0 n N More than 5% fines) no fines. GM Silty gravels, g ravel- sand -silt mixtures, non -plastic C/) M U3 50% of coarse fraction is C) C 0 W a) > larger than No. Gravels with fines fines. M.T z E Cn 4 sieve GC Clayey gravels, gravel -sand -clay mixtures, plastic fines. q C:) 0 C:) 04 Clean SW Well -graded sands, gravelly sands, little or no fines. LO 6 SANDS Sands SP Poorly -graded sands or gravelly sands, little or no III CZ CD M (less than More than 5% fines) fines. < 50% of coarse 0 0 fraction is SM Silty sands, sand -silt mixtures, non -plastic fines. 0 2 smaller than Sands SIC Clayey sands, sand -clay mixtures, plastic fines. No. 4 sieve with fines — ML Inorganic silts, rock flour, clayey silts with slight U) .2 C:) SILTS AND CLAYS plasticity. _j Q) C 10 M N U) CL Inorganic clays of low to medium plasticity, (lean clay). E 6 a) Liquid limit is less than 50% OL Organic silts and organic clays 'of low plasticity. 0 Z N W 0 C= Z to M (D MH Inorganic silts, elastic. -r— > < C 4-0 ai In P SILTS AND CLAYS W E CH Inorganic clays of high plasticity, fat clays. Z 0 Cn 5; Liquid limit is greater than 50% ILL OH Organic clays of high plasticity. HIGHLY ORGANIC SOILS PT Peat. DEFINITION OF TERMS AND SYMBOLS U) U) Standard Penetration Density Resistance in Blows/Foot 2" OUTSIDE DIAMETER SPLIT W _j SPOON SAMPLER z 0 Very loose 0-4 2.4" INSIDE DIAMETER RING SAMPLER Fn Loose 4-10 OR SHELBY TUBE SAMPLER W Medium dense 10-30 M 0 Dense 30-50 WATER LEVEL (DATE) 0 Very dense >50 Tr TORVANE READINGS, tsf Pp PENETR OMETER READING, tsf Standard Penetration W Consisten Resistance in Blows/Foot DID DRY DENSITY, pounds per cubic foot > U) Very soft 0-2 LL LIQUID LIMIT, percent W Soft 2-4 X 0 Medium stiff 4-8 PI PLASTIC INDEX stiff 8-16 Very stiff 16-32 N STANDARD PENETRATION, blows per foot Hard >32 Terra UNIFIED SOIL CLASSIFICATION SYSTEM Associates, Inc. POINT EDWARDS CONDOMINIUMS EDMONDS, WASHINGTON Consultants in Geotechnical Engineering Geology and Environmental Earth Sciences Proj. No. T-4893 I Date JULY 2003 1 Figure 3 Boring No. B-101 Logged by: TA Date: 6/18/03 Approximate Elev. 105 Soil Description Consistency/ Relative Depth E (N). Blows/ Moisture Content Density (ft.) ft. N FILL: dark brown silty sand with gravel, moist. (SM) Dense T 30 10 Brown silty SAND, trace gravel, with oxidized stained, moist. (SM) Brown mottled gray between 2. 5 to 4.0 feet. Medium Dens . e - 5 I 17 11 12 15 Gray, lean CLAY, trace subrounded gravel, moist. (CL) 7 20 —10 Medium - 22 27 stiff to Occasional light gray silt seams below 15 feet. Hard —15 20 35 44 26 26 Gray silty SAND, wet. (SM) Dense Gray, lean CLAY with light gray SILT seams. Hard —25 32 29 Boring terminated at 26.5 feet. Groundwater seepage encountered at 21 feet. Terra BORING LOG Associates, Inc 4 Consultants in Geotechnical Engineering Geology and Environmental Earth Sciences POINT EDWARDS CONDOMINIUMS . EDMONDS, WASHINGTON Proj. No. T-4893 I Date JULY 20031 Figure 4 Boring No. B-102 Logged by: TA Date: 6/18/03 Approximate Elev. 125 Soil Description Consistency/ Relative Density Depth (ft.) E 10 U) (N) Blows/ ft. Moisture Content N FILL: brown silty sand, trace gravel/clayey silt, moist. (SM/ML) Medium Dense to Very Loose —10 20 30 —40 50 15 13 9 3 2 24 22 29 33 29 38 37 32 19 5 7 11 10 23 31 36 26 27 25 27 25 Gray, lean CLAY, occasional light gray silt and sandy silt seams (1 to 2 mm), moist. (CL) 0.5 inches light gray sandy silt seam at 26 feet. 0.5 inches sand seam at 30.5 feet. Very stiff Gray SAND with silt, free water. (SM) Dense Gray, lean CLAY, moist. (CL) Boring terminated at 51.5 feet. Groundwater encountered at 40 feet. Terra Associates, Inc Consultants in Geotechnical Engineering Geology and Environmental Earffi Sciences BORING LOG POINT EDWARDS CONDOMINIUMS EDMONDS, WASHINGTON Proj. No. T-4893 I Date JULY 20 5 Boring No. B-103 Logged by: TA Date: 6/18/03 Approximate Elev. 129 Soil Description Consistency/ Relative Density Depth CL E (N) Blows/ ft. Moisture Content N Notes CRUSHED GRAVEL Dense T 10 —15 - — 20 T......... —25 30 35 36 11 15 16 22 31 30 28 35 41 2 17 28 24 36 28 24 32 23 29 ... .......... . FILL: dark gray clayey SILT/silty SAND, trace gravel, moist. (MUSM) Medium Dense Brown silty SAND to SAND With silt, free water. (SM) Medium Dense Gray lean CLAY, moist. (CL) Brown lean.CLAY with oxidized stained between 15.0 to 15.5 feet. Wet soils encountered at 21.5 feet. Occasional light gray silt and silty sand seams encountered below 25 feet. 4 inches sand seam at 31 feet. Very stiff to Hard ............. ..... :::::. ....... ........ .............. . . Boring terminated at 36.5 feet. Groundwater seepage encountered at 8.5 feet. Water level at 22.15 feet on June 19, 2003. Terra Associates, Inc. Consultants in Geotechnical Engineering Geology and Environmental Earth Sciences BORING LOG POINT EDWARDS CONDOMINIUMS EDMONDS, WASHINGTON Proj. No. T-4893 I Date JULY 20'031 Figure 6 Boring No. B-4 Logged by: DPL Date: 12/16/02 Approximate Elev. 90 Soil Description Consistency/ Relative Depth E (N) Blows/ Moisture Content Density ft. N FILL (Old test pit): bluish -gray silty sand, fine grained, Loose wet, with a trace of wood particles. Appears disturbed. 7 27 FILL (Old test pit): mottled brown silty sand, fine grained, moist Medium Dense 10 17 21 31 FILL (Old test pit): brown silt and clay, moist, with a trace of brown organic material. -------------------------------------------------------------- Very Stiff Bluish-gray SILT to CLAY, low to medium plasticity. (ML/CL) Very stiff 17 28 Gray SILT to CLAY, moist, low to medium plasticity. (MLJCL) --------------------------------------------------------------------------------------------------- Very stiff —20 30 23 LL = 35.5 P1 = 11.5 Grayish -brown sandy SILT to clayey SILT, fine grained, moist. (ML) With thin partings of iron -stained, fine-grained sand. Very stiff 35 23 Grayish -brown clayey SILT to silty CLAY, moist. MUCL) With thin discontinuous lenses of gray to mottU gray i�ftqrained sand. ---------------------------------------------------------------------------------------- Very stiff —30 30 24 Gray silty SAND, fine grained, moist. (SM) Dense _F 37 15 ------------------------------------------------------------------------ ------------- Gray sandy SILT to clayey SILT, fine grained, moist, low plasticity. (MIL to MUCL) ------------ Hard —40 T 34 17 Gray clayey SILT, moist, low plasficity. (MUCL) sand. Hard 37 20 Gray sandy SILT to silty SAND, fine grained, moist, (MUSM) D ense —50 - T 32 19 47 18 —60 42 15 Boring terminated at 61.5 feet. No significant groundwater encountered. Terra BORING LOG Associates, Inc. POINT EDWARDS CONDOMINIUMS EDMONDS, WASHINGTON Consultants in,Geotechnical Engineering Geology and Environmental Earth Sciences Proj. No. T-4893 I Date JULY . 2003F Figure 7 Test Pit No. TP-1 Logged by: JCS Approximate Elev. 104 Date: 10/18/01 Depth Moisture Content (ft.) Soil Description 0— FILL: crushed rock surfacing over brown to gray silty sand to sandy silt, fine grain( firm, moist (SIVINQ Rusty brown silty SAND fine grained, medium dense, moist, with occasional finE \gravel and fine roots. (�M) Gray to mottled gray silty SAND, fine grained, medium dense to dense, moist, with occasional fine gravel. (SM) 5 Becomes ligh t brown at appro)(imately 6 feet. 10 1 Gray CLAY, hard, moist, massive. (CL) 26 PP = 4.5+ tons/fe LL = 35.8 1 1 PI = 15 15 1 Test pit terminated at 14 feet. No groundwater seepage. 20 Test Pit No. TP-2 Logged by: JCS Approximate Elev. 124 Date: 10/18/01 Depth Moisture (ft.) Soil Description Content 0— FILL: crushed rock surfacing over brown silty sand to sandy silt, fine grained, firm, moist. 4-inch thick o anic layer at base. (SMIML) (Old topsoil horizon) - Brown silty SAND, fine grained, medium dense, moist. (SM) Mottled grayish -brown silty SAND, fine grained, medium dense, moist. 20 5 (SM) Grayish -brown silty SAND, fine grained, medium dense to dense, moist. (SM) 10 1 Gray CLAY, hard, moist, laminated with light gray silt partings. (CL) Pp = 4.5+ 1 1 tons/ft' 151 Test pit terminated at 14 feet. No groundwater seepage. 20 KIFA TEST PIT LOGS Terra POINT EDWARDS CONDOMINIUMS Associates, Inc. EDMONDS, WASHINGTON Geotechnical Consultants Proj. No. T-4893 I Date JULY 2003 1 Figure 8 Test Pit No. TP-4 Logged by: JCS Date: 10/18/01 Depth (ft.) 0— FILL: light brown silty sand, fine grained, firm, dry to moist (SM) 27--in—ch-TRUck organic layer at base. (Old topsoil horizon) Light brown to tan silty SAND, fine grained, medium dense to dense, dry. (SM) Mottled grayish -brown silty SAND, fine grained, medium dense to dense, 29 5— moist. (SM) - LL = 42.7 - Light grayish -brown to light brown CLAY and SILT, hard, moist, laminated 29 PI = 19.7 - with partings of dark gray fine sand. (CUML) PP = 4.5+ 10— tonsife - Gray CLAY, hard, moist. (CL) PP = 4.5+ 29 tons/fe - Test pit terminated at 13 feet. 15— Trace groundwater seepage at 6 feet. 20 Soil Description Approximate Elev. 92 Moisture Content N TEST PIT LOGS Terra POINT EDWARDS CONDOMINIUMS Associates, Inc. EDMONDS, WASHINGTON Geotechnical Consultants Proj. No. T-4893 I Date JU.LY re 9 CANTILEVER SOLDIER PILE WALL OR SINGLE ROW TIEBACK WALL Pass I ve Earth Pressure = 400 pcf taken over 2 pile diameters Note: Value ncludes Safety Factor of 1.5. . . . . . . . . - - - - - K'I\\ I I \\\I\\ 1\ M X"' H 40* pcf + 75 psf Traffic Surcharge Where Applicable 7711 rMA A 40(H)* psf taken over pile diameter NOT TO SCALE INCREASE PR ESSURE BY 20 PERCENT WHERE WALL IS SURCHARGED BY BACKSLOPE OF 2:1 (HORIZONTAL:VERTICAQ OR FLATTER. Terra EARTH PRESSURE DIAGRAM POINT EDWARDS CONDOMINIUMS Associates, Inc. EDMONDS, WASHINGTON Consultants in Geotechnical Engineering Geology and Environmental Earth Sciences Proj. No. T-4893 I Date JULY 2003 Figure 12 SOLDIER PILE WALL WITH TWO OR MORE TIEBACKS 7 0. 2 (H) 15' 75 psf UNIFORM PRESSURE TRAFFIC H SURCHARGE WHERE APPLICABLE 23 (H)* psf APPLIED OVER PILE SPACING loo 2' 400 pcf/ft PASSIVE EARTH T/ PRESSURE APPLIED OVER 2(D) 23 (H)* psf APPLIED OVER PILE DIAMETER NOTE: VALUE INCLUDES SAFETY FACTOR OF 1.5 1 D NOT TO SCALE INCREASE PRESSURE BY 26 (H) WHERE WALL IS SURCHARGED BY BACKSLOPE �OF 2:1 (HORIZONTAL:VERTICAL) OR FLATTER. Terra EARTH PRESSURE DIAGRAM POINT EDWARDS CONDOMINIUMS A Associates, Inc.. EDMONDS, WASHINGTON consultants in Geotechnical Engineering Enviro Geology and Proj. No. T-4893 Date JULY 2003 Figure 13 nmental Earth Sciences No TIEDBACK SOLDIER PILE/LAGGING SHORING WALL TIEBACKS GROUTED IN THIS ZONE ALLOWABLE TIEBACK ADHESION CAPACITY IN ANCHOR ZONE=1000 psf NOTE: TIEBACK CAPACITIES ARE BASE ON INSTALLATION USING TREMIE GROUT METHOD NOT TO SCALE goTerra Associates, Inc. Consultants in Geotechnical Engineering Geology and Environmental Earth Sciences LOAD/NO LOAD ZONE DIAGRAM POINT EDWARDS CONDOMINIUMS EDMONDS, WASHINGTON Proj. No. T-4893 I Date JULY 2003 Figure 14 .TERRA ASSOCIATES, Inc. Consultants in Geotechnical Enginee and Environmental Earth Scien es JUL 2 JUL 2.-7 2005 June 24, 2005 Project No. T-4893 Mr. Ross Woods RECEIVED Point Edwards, LL@ 2801 Alaskan Waf,Suite 107 J U N 2 4 2005 Seattle, Washid on 98121 Subject: )Geologically Hazardous Areas Review - Proposed Building 5 Expansion BUILDING DEPT. Point Edwards Condominiums Edmonds, Washington - References: 1 Preliminary Geotechnical. Report, UNOCAL Site,,Project No. T-480, prepared by Terra Associates, Inc., dated November 21, 2001 2. Steep Slope Hazard Review, Point Edwards Condominiums (UNOCAL Site), Project No. T-4893, prepared by Terra Associates, Inc., dated December 13, 2002 3. Geologically Hazardous AreasReview,. Point Edwards Condominiums (UNOCAL Site), Project 'No. T-4893, prepared by Terra Associates, Inc., dated January 20, 2003 Dear Mr. Woods: As requested, we conducted a review of geologically: hazardous areas pertaining to the proposed expansion of Building 5 dthe, Point Edwards Condominiums project. Our scope of work inclu . ded a vi . sual site reconnaissance and review of the referenced documents. Our study specifically addresses potential impacts to the erosion hazard areas (EHAs) and landslide hazard areas (LHAs) located on the steep slope west-northwest of the planned expansion. tThe expanded Building 5 footprint and delineated -hazard area are shown on Figure, 1. PROJECT DESCRIIPTION Buildingf 5 is located near the top of a steep natural slope'. in the northern portion of. the Point Edwards develd6ment area.' . Topographic information shown on a Grading and Temporary Erosion and Sedimentation Control*Plan by Triad Associates, dated July 28, 2003 (revised June 23, 2005) indicates the slope located west- northwest of the planned building'ar"ea is approximately 70 -to RO. feet -high, With inclinations ranging between about 50 and 80 percent. As shown on' the referenced topographic plan, the vast majo—firy-of Ille weste­m—sl—opelis iaentifi—ed-as a geologLcally- hazardous area with respect to erosion and landslide hazards. The pl—an—show _s1li_e—T07- foot buffer and 15-fo6t building setback from the top of the slope. that was recommended in our previous studies. _------------- - - -- — ------------ The plan indicates that the western side of Building 5 will be expanded to the southwestt generally paralleling the top of the steep slope. The remaining portio'hs of the Building �- footprint are generally similar to* ear1i_er_3e­s1`gns_ The building will consist of two floors, constructed over a basement level that daylights to the north and northwest. Planned lower * floor elevations Will be Elev. 7, and Elev..86.17, stepping up from east to west. Excavation.to accommodate the daylight lower level of the expanded portion of the building will extend from the northem edge of the building to the, face of th6 slope, resulting in a relatively flat I yard at approximately Elev. 86. 2525 Willows Road,' Suite 101, Kirkland, Wash ington'98034 Phone (42.5)'A21-7777 to Fax (425) 821-4334 Mr. Ross Woods June 24, 2005 Surface . water runoff from yard areas between the proposed building expansion and the steep slope will be as collected in four Yard draiihs and roui.ed in a closed system to the stormwater detention pond located at the b e of the slop e, northea.st?offf Building 5. . No stormwater runoff will flow over the crest of the slope. The planned ad and Strom Drainage plans prepared by Triad stormwater drainage system is shown on the revised Ro Associates. PREVIOUS STUDIES Terra Associates; Inc. (Terra) previously conducted critical areas studies for the Point Edwards Condominiums A project. The iesu,ln of these studies are documented in the referenced Steep Slope Hazard Review report'and AP dous Areas Review report. These studies were based on our visual observations and - Geologically Hazar subsurface investigations performed at the site since 2001, and included computer analysis of slope stabi.ity'a ong f Building 5. five section liges, including the steep slope area adjacent the northwestern comer o The refeiencId reports were prepared in general conformance with the r,equirements of Section 23.40.090 of the Edmonds Mimicipal Code (EMC) (Critical Areas, Report — Requirements) and EMC Section 23.80.050 (Special Study and R8eport 'Requirements — Geologically Hazardous Areas.) The methodology used for the studies documented * t the referenced reports andour current study is consistent with local professional practices, meeting the requirem; 6nt for use of best available. science per Section 23..40,090(C) of the EMC. areas containing LHAs and EHAs are The conclusion' of our previous studies regarding potential impacts to slope summarized below-.' • The,steep slope areas in the"westem portion of the site are- stable with respect to deep-seated failure under static conditions and severe seismic loading conditions • Thetproposed development will not decrease the stability. of the site or adjacent properties- duri ng or after site development. Po , tential ero I sion and sedimentatio . n impacts to the LHAs and EHAs due to the planned building locations will be'eliminated or significantly reduced,by applying Best Management Practices (BMPs) for erosion preventionsedimentation containment. P�otential impacts to -the stability of the steep slope'due to building surcharges, and potential impacts to the Buildings due to loss of shallow soil support, will be, mitigated by establishing appropriate setbacks. from the slope, and if necessary, supporting building loads with a, deep foundation system consisting of piles or 1 'donvent . ibnal*foundations- extended to appropriate depths. Pote . ntial erosion and . sedimentation impacts to the L . HAs and. EHAs due to proposed yard grading will be eliminated',or significantly, reduced by applying BM . Ps . for erosion prevention and sedimentation containment. • Proposed -grading will remove a significant volume of material from the top of the slope, resulting in a net reduction of soil load imposed on the slope and; therefore, improving slope stability. • Drainage systems associated'.with the finished buildings Will-, improve the current sta I bility of. the steep slope. • Improveddrainage of surface water from proposed yard areas will positively affect slope stability. • A reduction in the steep slope buffer� from 5 0 f6et to 10 feet will have no significant impact on the LHAs, EHAs, or adjacent slopes.. Project No. T-4893 . Page, No. 2 W. Ross Woods June 24, 2005 Conditions on the slo e I p ocated northwest of the Building 5 expansion have not changed since our previous studies, with the exception of the installation of extensive BMPs for erosion prevention and sedimentation. control associated with the,�lope rev'egetation activities that occurred in early 2004. Based on our observations of existing the. existing site conditions and our review of the proposed building location and associated grading, it. Is our opinion that the -conclusions of our previous studies,w'ould also apply to the planned expansion of Buil . ding 5. POTENTIAL IMPACTS AND MITIGATION As discussed, yard griding associated . with the planned expansion of Building 5 will encroach into the LHA and 00 EHA on the adjacent slope, and the associated slope buffer. This alteration will result in a modified top-of-40 percent slope that is about eight feet farther from the edge of the building, and about four feet lower.in, elevation than the existin g' too'0-40 percent slope demarcation. Potential impabts to the critical areas on the slope due to the planned location of the building expansion and yard grading include increasing the potential for erosion and sedimentation by exposing soils above the top of the slope during construction, and allowing uncontrolled surface water flow onto the slope. Potential impacts to slope stability indude building surcharges at the top of the slope and uncontrolled surface water flow onto the slope face. In our opinion, the potential for erosion during construction will. be eliminated or significantly reduced with proper application and maintenance of Best Management Practices (BMPs) for erosion prevention, sedimentation. containment, and surface water control,- as recomm* ended in our referenced reports. Potential impacts to slope stabil ity due to building surcharges, and potential impacts to the building due to its proximity to the slope will.be mitigated by the recommended buff6r and building setback determined using best available science. Potential impacts to slope stability due to uncontrolled stormwater runoff will be mitigated during construction With proper application and maintenance of BMPs for surface water control Post construction mitigation will be provided by establishing yard grades to direct surface water flow away from the slope and into four permanent yard drains that are connected to the storm sewer system. Standard maintenance of the storm sewer system will further reduce potential impacts associated with post -construction drainage of surface water. Because the proposed grading for the building expansion will result in a net reduction of soil load imposed on the slope, there will be enhancement to the current stability of the slope. Improved drainage at the top of the slope associated with the permanent building and yard drains will- also have a positive affect on slope stability. DISCUSSION Section 23.40.000 of the, EMC (Environmentally: Critical Areas General Provisions) states that "the purpose of this, title. is'designate and classify ecologically sensitive and hazardous areas and to protect these areas and their functions and values; while also allowing reasonable use of private property." In our opinion, the'LHA and EHA on the slope have ' a beneficial function and. value solely related to erosion control and protection from hazards. Section 23.40.050 of the EMC (Pro*te'ction-of Critical Areas) requires that any action taken result in equivalent or greater functions and'values of the critical areas, as ddtermm'ed by the best available science, Based on our study, and provided the recommendations. for mitigation presented in our referenced reports and herein ate followed, it is our opinion that the current development proposal will have no adverse impact to the critical areas located on the slope, and will not result in a net I o*ss of critical area function and value. Furthermore, it is our opinion that the planned development, along with -the recommended mitigation, will enhance the critical'area function and value. with modest improvements -to the stability of the slope due to load reduction and implementation of permanent drainage measures, and superior erosion prevention measures. Project No., T-4893 Page No. 3 Mi. Ros� Woods June 24, 2005 Because impacts to the LRA, EHA, and slope buffer cannot be completely avoided, revisions were made to the building design.and associated yard.grading to minimize impacts to the LHA, EHA, and buffer, in accordance with Section 23.40.120(2) of the EMC (Mitigation Sequencing.) The previous design considered constructing the building with its lower floor constructed at Elev. 82.17. Associated yard gradmig maintained a grade of approximately Elev. 82.0 from the edge of the building to the face o . f the slope. The revised proposal includes raising lower level floor elevations in the central portion of the building and the western building expansion by 2 and 4 feet, respectively. This permitted final grades between the buildmig expansion and the slope to be raised by .4 feet, and*results in a0structure that better conforms to,existing site grades. These design revisions significantly reduce the required/ excavation'volumes, and minunize impacts to the LHA, EHA, and slope buffer on the, adjacent slope. The total redu.ctio . n of excavation volumes -resulting from ' the redesign of the building is estimated to be approximately 4,150 cubic yards (cy). This total volume includes 200 cy in the 40 percent slope area, 300 cy in the slope buffer, 650,cy in the building setback area, and 3,000 cy within, the building area. Additional mitigation sequencing required by EMC Sections 23.40.120(4), (5), and.(7) are complied with by implementing permanent site drainage"and BMPs for erosion prevention in the hazard area. Periodic monitoring and annual maintenance of these measures will further reduce long-term hazard potential. According to Section 23.90.060 of the EMC (Development Standards — General Requirements) alterations of geologically hazardous areas or associated buffers may only occur for activities that: Will not increase the threat of the geologic hazard to adjacent properties beyond predevelopment conditions: Provided the recommendations for mitigation of potential impacts � contained. herein and in the referenced reports are applied, it is,'our opinion that the proposed alterations to the LHA, EHA, and buffer will not increase the threat of the potential hazards. Proper application of BMPs. for erosion prevention and sedimentation control, along, with the significant improvements in surface and subsurface drainage ad m nate or significantly reduce'the potential for erosion in thedevelopment j acent to the slope,. will eli � i area. The alteration to the geologic hazard areas and buffer will remove a -moderate volume of soil from the top of the, steep slope. This reductio n of load, and improvements in site drainage and. ero s*ion prevention will result in'a net *increase in the stability of the slope. 2. Will not adversely impact other ditical.areas. There are no other critical. areas near the steep slope. 1 Are designed so that the. hazard to the project is eliminated or mitigated to a level equal.to or less than predevelopment conditions.' The design of Building 5 has applied the use of appropriate setbacks, deepened. foundations, stepped. excavations, and surface and subsurface drainage based on best available science. 'In our:.opmio . n, these -design comiderations satisfactorily mitigate potential hazards associated with the steep slope. 4. Are certified as safe as designed,and under anticipated conditions by a qualifie.d"engineer or geologist, licensed in the State of Washington. Based on the results of our studies, and provided the recommendations � for hazard mitigation and geotechnical design and constructio'n-presented in our referenced reports are,followed, it is our opinion that the alterations to the geologic hazard areas land buffer associated with the proposed expansion of Building 5 will not'result in significant adverse impacts to the LHA and EHA on the . adjacent slope.. It is also our opinion. that the presence of the LHA and'EHA will not adversely affect the'stibility of the building as planned., Project No. T-4.893 Page No.4 Mr. '.RovWoods June 24, 2065 As discussed herein and in -the referenced repo . rts, it is our opinion that the requirements of Section 23.80.070 of . the EMC (Development Standards — Specific Hazards) have been met through detailed analyses, building design considerations, geotechnical recommendations for design and construction, and recommendations for mitigation of potential . hazards associated with the planned proposal. '.Specifically, Section 2 . 3.80.07.0(A)(2) of the. EMC (Al terations) states that alterations of an * erosion or landslide hazard area and/or - buffer may only occur for activities for which a hazards analysis is submitted'and certifies that: The developmeEnt will not increase surface water discharge or sedimentation to adjacent properties beyond predevelop mient conditions. In our opinion, the proposed project will ' not. increase uncontrolled surface water discharge or sedimentation beyond predeveippmeni conditions., ' The, proposed grading west of the building signifi, . cantly improves the ability to collect and route surface runoff into the storm drain systern.'. Proper application of recommended mitigation for erosion prevention and sedimentation control will eliminate or significantly reduce the potential for off -site sediment transport. 2. The development will not decrease slope stability on adjacent properties. The results of our studies indicate that- the stability of the slope will be improved as a result of load reduction due to grading, improved drainage, and proper application of recommended mitigation for erosion prevention and sedimentation control. 3. Such alterations will not adversely impact other critical areas. There are no other critical areas near the steep, slope. SUMMARY Based on our study, and provided the recommendations for mitigation presented in our referenced reports and herein are followed, it is our opinion that the current development proposal wil.l.have no adverse impact to the critical areas located on the slope, and will not, result in a net loss of critical area fun6tion*and value. Furthermore, it is our opinion that the planned development, along,with the recommended mitigation, I will enhance the critical area -function and value with modest improvements to the stability of the slope due to load reduction, and -implementation of permanent drainage measuresi and superior eros . ion prevention measures. In our -opinion, the development proposal and proposed mitigation, complie's with the telev ant requirements of EMC Section 23.40.160 (Review Criteria) as discussed below. Impacts to the LHA and EHA are minimized through mitigation sequencing consistent with the requi I rements of EMC. Sectio- n 23.40.120, including minimi . zing impacts by -,project redesign; minimizing or eliminating hazards through engineering or other methods (permanent drainage measures and BMPs for permanent erosion prevention and sedimentation control);_ further reducing impacts or hazards with annual maintenance and monitoring. The proposal does not pose an unreasonable threat.to,public health, safety, or welfare. -1he slope adjacent the proposed building expm'sion is currently stable. The.planned development will not. increase the hazard, but will improve the stability of I the slope through reduction of'soil load at the.top of thestope, improved drainage, and implementation of permanent BN[Ps for erosion prevention and sedimentation control. Project No. T-4893 Page No. 5 Mr. Rns Woods iune 24, 2005 • By limiting the alteration of the critical areas, and enhancing slope stability and erosion protection, the devel I opmeni proposal allows reasonable u se of the - property and protects human health *and the environment in conformance.with the general purposes of critical areas ordinance and public interest. • Mitigation of potential, impacts to the critical areas are based. on best available science and will enhance the existing function and value of the critical areas with modest improvements to the stability of the slope due to soil loadreduction and, implementation of permanent drainage measures, and superior erosion -prevention measures. • The development pr . oposal protects and enhances the benefkial functions and values of the EHA and LHA (erosion control and protection. from hazards.) We trust the information presented is sufficient for your current needs. If you have, any questions or require additional inf6rmation, please call. �OVWO'15�as �h ash,, .4 e-_<a0_ Sincerely yours, TERRA ASSOCIATES, INC. John C."Sadler, L.E.G., L.H.G. ProjectManager Encl. Figure 1 — Site Plan Preliminary Geotechnical Report Steep Slope Hazard Review Geologically Ha zardous Areas Review cc: Mr. Richard E. Gifford li I JOHN C. SADLER I Project No. T74893. Page No. 6 LL, 0 k. it I Co ca 0 j c"i cy 00 I I f _J CV) C\1 CID _1 n:� # N. N. f ;11 If qjl to to ro V� �6 t6 cr. V IN N V` A L) It , V o" V% A, 17 "4r, Ij_d.j .1 h A it uu I I Ir 10 A. "M r it Q), C) L LLJ U) LLJ N. 1 f IN ji. ri-r CD 4 Wr, LO A-9 IN IN, N, IN , X. I, v. , T IN IN I IN I N, I It I IN I \\\ \ v IN` I, IN N. LL_ if Y, N, I IN. IN I N, NN, I I, OQ c) I IN I v I I - _j I \ I I — A\ N, IN o\v v I N \ IN I I IN I \'\' I I, . 111IX NN\ \ I I \\ I I I " 'IN NN IN \N IN I I I I I I I IN I I V\ IN N, IN, IN I N, N\ I A I \ I , , 1, , \ I % I I,k N. IN I N, X v A IN IN 1, IN IN'\ IN IN \ N. 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CL ui oz o E U;.ui z Z Lu z :5 to zir a UJ Ul Z5, w UJ a. WLL.uj Ir a ui z . . . w 14 TERRA ASSOCIATES nc. A A A 46 A Consultants. in Geote c.hnical'Engineering, Geology and Environmental Earth Sciences September 1, 2005 Project No. T-4893 Mr. Ross. Woods Point Edwar&, LLC 2801 Maskan W Suite 107 V; RFEmiB Seattle, Washingion 98121 SEP -6 2005 Subject Seismic Wall Pressure and Pile Nint-of�Fixity — Building.5 Poirit.Edwards Condominiums ­31UILOING DEPARTMENT Pine Street and Unoco Road.:. ciTY OF EEMMONDS Edmonds, Washington References: -I. Supplementary Subsurface Exploration, Point Edwards Condominiums, Project No T4893, prepared by Terra Associates,.Inc.,,dated July 30, 2003 2. Prehmirwy. Geotechnical Report, UNOCAL Sfte, Project'No. T-4893, prepared by Terra Associiates,! Inc.,, dated November 21, 2001 Dear -Mr. Woods: As a Nlow7up to otir conversation with DO Engineers, we are provid�ng. a -horiz.onw'scismic earth pressure value for use. in the subject project'swall design.. DCI Engineers also requires dpoint-of-fixitydeterminaii.on for us . e in design of piles I&atedat the northern perimeter of Building adjacent tothe northern slope. The results of our analyges follow:, Seismic Earth Pressure: Our -analysis of a. design seismic earth pressure value was. -completed'using methods -outlin6d'in "Design -of Earth Retaining . Structures For . Dynantic' Loads," by H. Bolton Seed and Robert- V. Whitman (1970). Based on our.analysis, a unifohn horizontally -applied seismic -earth pressure -value of 17H psf can be used in wall design, where H is the in feet The. seismic earth pressure value was calculated based on a 2:1 (11brizontal:Veitical) 'fill back slope adjacent to the back of the wall. -and' a design horizontal seismic acceleration value of 0. 1 69g (provided by DCI Engineers). Pile, Point-of-Fix1ity: The structural plans indicate 18-inch diameter augercast piles planned for construction at .the northern perimeter of Building 5 will have a minimum length Of 15 feet below the grade beam. Based on observed soil conditions during -construction, and the results of our p . revious explorations, we anticipate piles will extend primarily into the site's hard clay. For these soils and pile dimensions, and as a free -head condition SUMM9 at the tpp of the pile, analysis yields a point -of -fixity (depth to zero pile shear) located at a depth of 5 feet below the top of the pile. 8-TREETALE 12525 Willows Road, Suite 101, Kirkland, Washington 98034 "IL - - IAft"% n�4 -Y�-Y-r . r_ IA'Nrl OnI A-)-�A Mr. Ross Woods September 1, 2005 We trust the information presented is sufficient for your current needs. If you have any questions or require additional information, please call. Sincerely yours, TERRA ASSOCIATES, INC. 'C:;;m "C a 0 . Sadler, L.E. Project Manager Kevin P. Roberts, P.E. Senior Engineer cc: Mr. Jeff Brink, P.E., DCI Engineers Project No. T4893 Page No. 2 h Mr. Ross Woods Point Edwards, LLC 2801 Alaskan Way, Suite 107 Seattle, Washington 98121 TERRA ASSOCIATES, Inc. Consultants in Geotechnical Engineering, Geology and Environmental Earth Sciences January 20, 2003 Project No. T-4893 JUL 2 RECEIVED B'i 1 rl 9 i Subject: Geologically Hazardous Areas Review Point Edwards Condominiums (UNOCAL Site) Pine Street and Unoco Road Edmonds, Washington T, 711'r;1 _'9�ILDING DEPT. JUL 2 7 2005 'V. Cie B Y.- References: 1. Preliminary Geotechnical Report, UNOCAL Site, Project No. T-4893, prepared by Terra Associates, Inc., dated November 21, 2001 2. Steep Slope Hazard Review, Point Edwards Condominiums (UNOCAL Site), Project No. T-4893, prepared by Terra Associates, Inc., dated December 13, 2002 Dear Mr. Woods: As requested, we have conducted a review of geologically hazardous areas for the Point Edwards Condominiums site. The location of the site is shown on the attached Figure 1. Our scope of work included a visual site reconnaissance, the drilling of five test borings to depths ranging from about 31.5 feet to 61.5 feet below the existing ground surface, and review of the referenced reports. Our study specifically addresses erosion hazards, landslide hazards, and seismic hazards. We previously addressed steep slope hazards at the site. Our current study includes analysis of slope stability along five profiles on the steep slopes located downgradient from the proposed development. The results of these analyses are used to address potential steep slope hazards and landslide hazards. SITE CONDITIONS The site is located on the upper portion of a predominantly north -facing hillside. The Preliminary Grading Plan indicates elevations in the planned development area range from about Elev. 170 in the south-central portion to about Elev. 70 in the northeastern portion. The western and northern margins of the planned development area are near the top of a steep natural slope. The topographic information provided to us indicates the slope is approximately 70 to 90 feet high, with inclinations ranging between about 50 and 80 percent. The areas beyond the toe of the slope to the north-northwest are relatively flat. Burlington Northern railroad tracks run along the toe of the slope to the west. __ —IN I W 12525 Willows Road, Suite 101, Kirkland, Washington 98034 Phone (425) 821-7777 9 Fax (425) 821-4334 Mr. Ross Woods January 20, 2003 hi We did not observe indications of deep-seated instability; however, portions of the slope have been subjected to shallow erosion and localized sloughing. These conditions are generally limited to the forest duff and relatively loose surficial. soils mantling the underlying competent soils, and are commonly associated with natural weathering occurrences on steep slopes. All of the erosional features we observed on the steep slope appear to be a result of surface water runoff and shallow interflow from areas above the slope crest. We observed an area approximately 100 to 125 feet southwest of Boring B-1 where the top of the steep slope has sloughed, exposing dense to very dense silty sand with gravel in a 7- to 8-foot high, near -vertical face, just below the crest of the steep slope. Based on our observations, it appears that the sloughing at this location also occurred as a result of concentrated surface water runoff and shallow interflow from areas above the slope crest. We observed a very light trickle of water flowing into this feature from the relatively flat upland above the slope. Slope vegetation consists predominantly of young to mature deciduous trees and brush. GEOLOGIC CONDITIONS The Geologic Map of the Edmonds East and Part of the Edmonds West Quadrangles, Washington by James P. Minard, 1983, shows the soils at higher site elevations mapped as Vashon till, Vashon advance outwash, and Transitional beds. Soils at lower site elevations are mapped as medium- to coarse -grained sand of the Whidbey Formation. Transitional bed sediments are described by this publication as massive to bedded clay, silt, and fine to very fine sand. Our recent test borings and the test pits performed as part of our referenced preliminary geotechnical study are generally consistent with the descriptions of transitional bed deposits. The soils we observed on and immediately above the steep slope areas generally consist of silty sand, sandy silts, and laminated to massive, very dense silt and/or hard clay. Native soils observed in the five test borings drilled near the top. of the steep slopes generally -grained silty sand to sand with silt, and very stiff clay/dense silt. The silt and consist of dense to very dense fine clay generally appeared massive, with occasional very thin partings of very fine sand. The native soils are generally moist below a depth of about five feet. We observed wet soils to a depth of about ten feet in Boring B-3. We did not observe indications of significant groundwater seepage on the slope; however, we observed wet surficial soils in one isolated area near the top of the steep slope, west of the proposed development. The wet conditions at this location appear to be from surface runoff from areas above the top of the steep slope, and possibly from seasonal perched groundwater emerging near the top of the slope. We also observed a very light flow of water along the axis of several of the erosional channels running down the Am steep slope. The water we observed in the erosional features flows on top of dense to very dense native soils exposed on the ground surface or beneath approximately 4 to 12 inches of duff and topsoil. The source of the water in the erosional features appears to be surface runoff from areas above the crest of the steep slope. Detailed descriptions of the subsurface conditions encountered in the test pits and test borings are presented on the attached test pit logs and boring logs. The approximate locations of the test pits and borings are shown on the attached Figure 2. Project No. T-4893 Page No. 2 L;� Kz;i Mr. Ross Woods January 20, 2003 GEOLOGICALLY HAZARDOUS AREAS Section 20.15B.060 (A)(3) of the City of Edmonds Community Development Code (ECDC) defines geologically hazardous areas as those areas subject to potential erosion, landslide, and/or potential seismic instabilities, including the following: 0" Erosion Hazard Areas Section 20.15B.060 (A)(3)(a) of the ECDC defines erosion hazard areas (EHAs) as those areas containing soils qw that may experience severe to very severe erosion hazard. These soils include, but are not limited to, the following when they occur on slopes of 15 percent or greater: 1. Alderwood soils (15 to 25 percent slopes) 2. Alderwood-Everett Series (25 to 70 percent slopes) 3. Everett Series (15 to 25 percent slopes) The Soil Conservation Service (SCS) has mapped the site soils as Alderwood-Urban land complex, 2 to 8 percent slopes, and Kitsap silt loam, 8 to 25 percent slopes, in the upper southern portion of the site, and Alderwood- Everett gravelly sandy loam, 25 to 70 percent slopes, in the area of the former tank farm and the steep slope below the tank farm area. The soils we observed in the test pits generally conform with the SCS mapping; however, some of the very dense silt and hard clay we observed in the former tank areas would better correlate with Kitsap silt loam, 25 to 50 percent slopes, due to existing man-made slope gradients. The erosion hazards for soils classified as Alderwood-Urban land complex, 2 to 8 percent slopes, and Kitsap silt loam, 8 to 25 percent slopes, are classified as slight and moderate, respectively, and do not fall under the classification of an erosion hazard area. Alderwood-Everett gravelly sandy loam, 25 to 70 percent slopes, is classified as having a moderate to high erosion hazard. The erosion hazard for soils classified as Kitsap silt loam, 25 to 50 percent slopes, is considered high. Based on the criteria presented above, the portions of the site that are sloped at inclinations greater than 15 percent and are underlain by Alderwood-Everett gravelly sandy loam would be considered an EHA. Areas underlain by Kitsap silt loam that are inclined at a gradient steeper than 25 percent would also be considered EHAs. Based on observations, the vast majority of the site located downgradient from Pine Street would be considered an EHA. EHAs, based on the SCS mapping, are shown on the attached Figure 3. We did not observe indications of significant active erosion in the planned development area; however, the soils will be susceptible to erosion when exposed during construction. In our opinion, Best Management Practices (BMPs) used during construction will provide adequate mitigation of the erosion hazard at the site. If the erosion control measures are properly implemented and maintained, along with temporary and permanent drainage improvements, it is our opinion that the planned development will not adversely impact the erosion potential for the site or adjacent properties. All erosion and sediment control BMPs should conform to City of Edmonds requirements. Project No. T-4893 Page No. 3 L;; Mr. Ross Woods January 20, 2003 I" — Landslide Hazard Areas Section 20.15B.060 (A)(3)(b) of the ECDC defines landslide hazard areas (LHAs) as those areas of the city of Edmonds which, by reason of excessively steep slopes, unsatisfactory foundation support, stability, or topography, have a risk of earth subsidence and landslide hazard in excess of normal allowances. The ECDC specifies field criteria for identifying LHAs. We used these criteria, listed below, in our evaluation of LHAs at the subject site. 1. Any area with slopes of 15 percent or greater, and impermeable soils (typically silt and clay) frequently interbedded with granular soils (predominantly sand and gravel) and springs or groundwater seepage. 2. Any area that includes areas with significant visible evidence of groundwater seepage, and which also includes existing landslide deposits, regardless of slopes. 3. Any area that has shown movement during the Holocene epoch (from 10,000 years ago to present) or is underlain by mass wastage debris of that epoch, as determined by a qualified geologist or geotechnical. engineer. 4. Any area potentially unstable as a result of rapid stream incision or stream bank erosion. 40 5. Any area located on an alluvial fan presently subject to, or potentially subject to, inundation by debris flow or deposition of stream -transported sediments. During our site visit, we did not observe on -site indications of deep-seated instability, springs, or significant groundwater seepage on the steep slopes. As discussed, we observed relatively shallow erosional features and localized shallow sloughing at isolated locations on the steep slope located below the proposed development. Because shallow ground movements are associated with these erosional features, and considering that near - surface interflow likely contributed to the soil loss, these areas would be considered LHAs pursuant to Items 1 and 3. All of the LHAs we identified at the site exist on the steep slope hazard area (SSHA) (slope inclinations greater than 40 percent) located west of Buildings 5, 6, and 7. Stability Analysis We performed our stability analyses using the computer program WINSTABL. The soil parameters used are shown on the attached analysis plots and output text. These parameters are based on field and laboratory data, and our past experience with similar soils. Analyses of the slope were performed along five section lines identified on the attached Figure 2 as Section A -A' through Section E-E'. Our analyses of these sections considered both static and pseudostatic (seismic) conditions for the existing slopes, and for proposed grading with associated building loads at grade. This analysis is conservative, considering the buildings located near the top of the steep slope will be partially or completely supported by deep foundations. A horizontal acceleration of 0.20g was used in the pseudostatic analysis to simulate slope performance under earthquake loading. Project No. T-4893 Page No. 4 W Mr. Ross Woods January 20, 2003 The lowest safety factors for each condition are presented in the following table: Section Analyzed Minimum Safety FEtors Static Pseudostatic Section A -A' existing 1.72 1.18 Section A -A' proposed 1.79 1.21 Section B-13' existing 2.09 1.42 Section B-B' proposed 1.56 1.16 Section C-C' existing 2.32 1.53 Section C-C' proposed 1.67 1.26 Section D-D' existing 1.88 1.24 Section D-D' proposed 2.03 1.33 Section E-E' existing 1.72 1.15 Section E-E' proposed 1.60 1.26 The results of the stability analyses indicate that existing and proposed slopes are stable with respect to deep- seated failure under static conditions. The existing and proposed slopes are indicated to be stable to marginally stable under severe seismic loading conditions. Potential impacts to the LHAs due to construction of the buildings and proposed yard grading include increasing the potential for erosion on and/or adjacent to the slope by exposing soils during grading and allowing surface runoff to flow onto the steep slope, and impacts to slope stability from building surcharges. In our opinion, potential erosion and sedimentation impacts to the LHAs due to the planned building locations and yard grading will be eliminated or significantly reduced by applying BMPs for erosion prevention sedimentation contairurient. As discussed above, analysis indicates the existing and proposed slope conditions are stable with regard to deep- seated failure. In our opinion, supporting building loads with a deep foundation system will further reduce potential impacts to the stability of the steep slopes due to building surcharges, and mitigate the landslide hazard. A deep foundation system will also eliminate the potential of adverse impacts to the stability of the buildings in the event of shallow soil loss adjacent to the buildings. Additionally, drainage systems associated with the finished buildings will improve the current stability of the steep slope. Seismic Hazard Areas Section 20.15B.060 (A)(3)(d) of the ECDC defines seismic hazard areas as those areas subject to severe risk of earthquake damage as a result of seismically induced landslides, earth adjustments, settlement, or soil liquefaction. Based on the soil and groundwater conditions we observed in our on -site explorations, and the results of our 7" stability analysis, it is our opinion that the risk for severe damage resulting from seismically induced landslides, earth adjustments, and settlement is low. It is also our opinion that the risk for liquefaction to occur in potential building areas at this site is negligible. Therefore, in our opinion, seismic hazard areas do not exist on the subject site. Project No. T-4893 "0 Page No. 5 Mr. Ross Woods January 20, 2003 DISCUSSION Section 20.15B.110 (B) of the ECDC (Development Standards — Erosion Hazard Areas) states that alterations within identified EHAs will not be authorized without an approved erosion control plan pursuant to Chapter 18.30 ECDC. A licensed engineer will prepare a site -specific erosion control plan conforming to the requirements of Chapter 18.30 ECDC. Section 20.15B.110 (C) of the ECDC (Development Standards — Landslide Hazard Areas) states that LHAs located on slopes greater than 40 percent shall be regulated pursuant to Section 20.15B.110 (D) of the ECDC (Development Standards — Steep Slope Hazard Areas). As discussed, the LHAs we identified at the site exist on the SSHA (slope inclinations greater than 40 percent) located west of Buildings 5, 6, and 7. We previously addressed SSHAs in the referenced report. In the SSHA report, we opined that existing site conditions and applicable project components generally meet the provisions for a SSHA exemption detailed in Section 20.15B. 1 10(D)(2)(a — g). Specifically, this exemption would apply to encroachment into SSHAs by proposed Buildings 5 and 6, yard grading associated with Buildings 2 and 6, and encroachment into the buffer within about 5 feet of the SSHA by Building 7 and its associated yard grading. We also opined that a reduction in the buffer from 50 feet to 10 feet will have no significant impact on the SSHA or adjacent slopes. In our opinion, the subsurface information and analytical results presented herein support the findings presented in our SSHA report, and the request for a SSHA exemption and buffer reduction. We trust the information presented is sufficient for your current needs. If you have any questions or require additional information, please call. Sincerely yours, TERRA ASSOCIATES, I IJ010.) "11��inity Map P?L4Vq'-- Exploration Location Plan ift—gV4_� ErosiaonlMazard Area/Soils Map ig 4 — Unifie Soils Classification System Figures 5 through 9 — Boring Logs Figures 10 through IS — Test Pit Logs WINSTABL Output Data cc: Mr. Greg Krabbe, Triad Associates Mr. Richard E. Gifford Mr. S. Jin Lee, Weber+Thompson Project No. T-4893 Page No. 6 61 41P 61 Lj 6; 0 I HUTT pl-IM4111. I 'C. 19�" PK WTI n Sw 187TH ST SIM I PLSH IT 1W t6ITI ST sw— I 89T)f S Yd ;11 Fk AKE. w T PL ST Sw 19M ST Sw;: CHEPR ST 0-1 96M C� 13 00roF4 Ad —Ilk ST SW PLTV PU D MELODY LN WY J4 HI LEY Eiit" - WY 2 - 9M BF100KNERE W L EOMONO'S UNDERWER wE S S PARK It BRACKETTS 404K VISTA 8(po LN WY T, at wy 1 ERRA MISY I 51 SW6 SM LANDING 0 - 8 GLEN XY 24 Z: PRAWE ELL ail ST- 2Q6TH Sw tA N ST PL PL TEH PL I -ra S MRIA14 P3 14APLE sw UNION IZ14001 w A 5 m4w OIL CEDAF ARK 212TH ST si ;U' SITE MAW I MCE t Z14TH PL MLOCK I re ST -I LAWL TWIL IN 21 2n] PH L '15TH ST Sw I IN- ST. I ;4"' 21ST-H EDWARD5 MR1194 216 PT BEACH POLVE YL MAKAH 34 21M %.SW F1 F R ST 21M. Sw K 26 IM 30- --LIA C-- 04 2 -4'T Af T UIST PL DOGhWo PL If REFERENCE: Thomas Guide, King/Pierce/Snohomish Counties, 1999, Page 454 NOT TO SCALE Terra VICINITY MAP POINT EDWARDS CONDOMINIUMS Associates, Inc. EDMONDS, WASHINGTON Consultants In Geotechnical Engineering Geology and Environmental Earth Sciences Proj. No. T-4893 I Date JAN 2003 Figure 1 - ---------- . ............. N, STEEP SLOPE ........... ri A z_- AM A D ANE N........... D -SLOPE ­­TP STEEP B 4 HAZAkD AREA., TP.-'- 12` . ....... .... ... _:/�000500* - ------_------------- ------ .......... .......... . 5 ... ..... --- ..... ..... ... ......... '21 le LDG 2 Br3 B .5 - --- - --------- __ Z�_, P-1 4 �',`:E, . . . . ........... .6 T -5 p :, . _. - '�-%013 R /BLDG 6 .2 TR BLDG:, T �71 3� 6� ------------------ .--- ?" . TP'l 6 BLD 4 ........ . 7777RZ�� TP 4 TIM --------- Ali I LUG l'OV'' mam S, BLI ----------- 17 TP TPA I W TP J _z_ Tz 150 300 pm NOTE: THIS SITE PLAN IS SCHEMATIC.* ALL LOCATIONS -AND L tdEN'D: AP . PROXIMATE SCAL . E IN FEET P4 APPR,0XIMATE LOCATION OF TEST PIT DIMENSIONS ARE APPROXIMATE. It IS INTENDED FOR EXPLORATION -LOCATION PLAN REFERENCE ONLY AND SHOULD NOT BE USED FOR'. DESIGN OR CONSTRUCTION PURPOSES. 'n =7 �7 TO rra' -OF BORING POINT ED RDS CONDOMINIUMS Bml! A0PROXIMATE10CATION WA. 'Ats6eiates Iric. EDIVIONDS,� WASHINGTON REFERENCE: StEEP "SLOPE HAZARD AREA Contultants In Peotechnical Ingineering Figui­6 Proj. No. T-4893 I!Xite JAN'2003 2 SITE PLAN PROVIDED BY TRIAD ASSOCIATES Geolog and Earth Sciences Environrhentaly N OTE: THIS SITE PLAN IS SCHEMATIC. ALL LOCATIONS AND DIMENSIONS ARE APPROXIMATE. IT IS INTENDED FOR REFERENCE ONLY AND SHOULD NOT BE USED FOR' DESIGN OR CONSTRUCTION PURPOSES. REFERENCE: .SITE PLAN PROVIDED BY TRIAD ASSOCIATES ............ ------------------ ............. ............. LEGEND: 1) Alderwood-Evereft gravelly sandy loams, 25 to 70% slopes 2) Aide rwood-Urba nland complex, 2 to.8% slopes 3) Kitsap Silt loam, 8 to 25% slopes = Erosion Hazard Area ............... .. ........... STEEP SLOPE HAZARD AREA 0 150 APPROXIMATE SCALE IN FEET, EROSION HAZARD AREA/SOILS MAP Terra POINT EDWARDS CONDOMINIUMS Associates Inc EDMONDS, WASHINGTON Constiltants In Geotechnical Ingineekn; Geology and - Proj. No. T-4893 Date JAN 2003 -.Figure 3 Environmental Earth Sciences MAJOR -DIVISIONS LETTER SYMBOL TYPICAL DESCRIPTION Clean GW Well -graded gravels, gravel-s6n d mixtures, little. or no GRAVELS Gravels fines. I Poorly -graded gravels, gravel-sandL mixtures, little or (n a) _j 0) (less than - W N More than 5%'fines) no. fines. GW Silty gravels, -gravel-sand-silt mixtures, non -plastic —'FD ca 50% of coarse, a) > fraction is larger than NO. Gravels fines. GC a y gravels, grave I -sand-clay mixturesi plastic fines. Cl'ye' LLJ � (D Z1 E sieve : with fines < 0 C\j Clean SW Well. -graded sands,, gravelly sands, litt.le-or no fines.' LO - ..0 SANDS'. Sand S Sp Poorly -graded. sands or- gravelly sands, little or no W Cz U) Cc; (less than C More than 5% fines)' fines. (D 50% of coarse 0 %_ 0 fraction is SM� Silty sands, sand -silt- mixtures, non -plastic fines. 0- _SM aller than Sands SC' Clayey. sands, sand -clay mixtures, plastic fines. No. 4 sieve with fines ML Inorganic silts, rock flour, clayey silts with.,slight. SILTS AND CLAYS plasticity. CL inorganic clays -of low to, medium plasticity, (lean clay). a) 0 0 — C\I, ca U) E 0 Liquid limit is'less than 50% 0 o Z.N LLI 0- CO OL Organic silts and organic clays of low plasticity. C:) C: z 10 cz (D - C (D MH inorganic silts, elastic. ca -C a) 0 � SILTS AND CLAYS =` . Q) Cz W " E CH' Inorganic clays of high plasticity, fat clays. Z 0 cn Liquid limit is greater than 50% OH organic clays'of high - plasticity. HIGHLY ORGANIC SOILS -PT -Peat. DEFINITION OF*TERMS AND SYMBOLS U) U) uj Standard Penetration DensitV Resistance in Blows/Foot 2"'OUT . SIDE DIAMETER SPLIT SPOON SAMPLER _j z 0 Very loose 0.4 2;4" INSIDE DIAMETER RING SAMPLER Loose 4-10 OR SHELBY TUBE'SAMPLER Medium dense 10-30 Dense 30-50 WATER LEVEL (DATE) 0 Very dense >50 Tr TORV . ANE READINGS, tsf Pp PENETROMETER READING, tsf Standard Penetration 'Consistenc Resistance in Blows/Foot DD DRY DENSITY, pounds per cubic foot W > UX Very soft 0-2 LL LIQUID LIMIT, percent W Soft 2-4 0 Med . ium stiff 4-8 PI PLASTIC INDEX 0, stiff 8-16 Very stiff 16-32 N STANDARD PENETRATION, blows per foot Hard .>32 .,UNIFIED -SOIL CLASSIFICATION* SYSTEM E§OTerra, Associat6s,Jnc. POINT EDWARDS CON DOM.1 N I UMS , I EDMONDS, WASHINGTON Consultants in Geotechnical Engineering Proj.'No. T-4893 Date JAN 2003 Figure .4' Geology and Environmental Earth Sciences Boring No. B-1 Logged.by: -JCS Date: 12/13/02 Approximate Elev, 110 Soil Description consistency/ Relative Depth CLI E Blowsf Moisture Content De sity Grayiih-brown silty SAND', fine grained, with occasional fine gravel. (SM) Medium' Dense 1 7 -.29 2. Occasional rusty brown stained partings. ------------------------------- 7 ----------------------- ------- -------------------------------- Dense 1 0 T- .43 1 4 Light brown SILT,with sand, fine grained,, moist, slightly mottled. (ML) ---------------------- ----------------------------------------------------------------------- Dense '42, 21 Mottled light brown silty SAND to sandy. $IL fine grained, moist to wet. (SM/MQ Dense 20, 38 23 Light gray silty SAND to sandy SILT, fine grained, moist, with occasional fine qraveljqM�M�) ...... ---------------------------- -------------------------------------------- Very Dense- 6 0 18 Grayish-brown SAND with silt, fine to medium grained,' moist, with occasional fine gravel.. (SP'_SM) very Dense 30 T '8' 2. 8 Grayish -brown SAND with silt to sifty,SAND, fine grained, moist. (SO-SWSM) Very Dense 58 15 (G rayish-brown hard, moist SILT between 35.5 and 36.0 feet) Light gray silty SAND. to SAND with silt, fine grained, Very —40 1 75 -10 moist. (SM/SP-SM) Dense Trace. of gravel. Very Dense .80 8 Very Pense 50 58 6 ------------------------------------------ ------------------------------------------------ Brownish-gray SAND with silt to silty,SAND, fine grained moist. (SP-SM/SM) With a trace of fine black.organic inclusions. ------- Very Dense :-E 82 10 No fine organic inclusions. Very Dense 86 8 Boring terminated at 60 feet. No significant groundwater encountered. Te r ra' BORING LOG - FE�.. As'sociates-, Inc., POI.NT EDWARDS CONDOMINIUMS EDMON DS, WAS HINGTON Consultants in Geotechnical Engineering Geology and Environmental Earth.Sclences Prbj. No. -T-4893 Date:JAN 2003 Fl 5 Boring No. B-2 Logged by: JCS Date: 12/13/02. Approximate Elev. 90 Soil Description, Consistency/, Relative Depth cL E (N) 'Blows/ Moisture Content Density (ft.) U) ft. N FILL: gray sandy silt, fine grained, moist, with occasional fine gravel. Loose 5 8 24 FILL: brown organic silty sand to sandy silt and bluish- gray silty sand, fine grained, moist to wet. Loose, ._10 4 12 With organics. Loose 15 6 '10 Very Loose 720 3 27 Bluish -gray to light brown SAND with silt to silty SAND, fine grained, moist. (SP-SM/SP) ---------------------------------- ------- --------------------------------------- Medium Dense ---------- —25 - - 20 13 Mottled gray sandy SILT, fine'grained, moist. (ML) ------------------------------------------------------------------------------------------------- Medium Dense, —30 - 23 20 Gray SAND to SAND with silt, fine grained, moist. (SP/SP-SM) Medium Dense _35 - 27 -10 Dense 40 :E 36 Boring terminated at 41.5 feet.. No significant grou'ridwa ter encountered. erra Associates 91 n c. BORING LOG POINT EDWARDS CONDOMINIUMS' EDMONDS,' WASHINGTON Consultants in Geotechnical Engineering Geology and Environm6nW Earth Scie _ nces Proj. No. T-48,93 j Date, JAN 2003 Figure 6 Boring No. .13-3 Logged by: DPL ,Date: 12/16/02 Approximate. Elev. 76 Soil Description Consistency/ Relative Depth, E (N) Blows/ Moisture Content Density (ft (0/0) Possible FILL: gray sand to silty sand, fine grained, wet, with occasional fine gravel. Possible FILL:. grayish -brown silty sand, fine grained, wet, ---- slight -mottling. ---------------------------------- I --- Medium ------- ---------- 5 11 .19 Pray silty SAND, fine grained, moist. (SM) Dens e 10 '. 3.1 22 .Gray silty SAND.to sandy SILT, fine grained, moist. Dense —15 36 .20 (SM/ML) ----------------------------------------------------------- --------------------------------------- Grayish-brown SAND with silt, fine grained, dry to moist. (SP-SM), Very Dense 20 68 4. Ve ry Dense .1-25 - 53 5 Grayish -brown SAND, fine grained, dry to moist. I (SP) very Dense, —.30 51 5 Boring terminated at 31.5 feet. Minor groundwater perched at 7 feet. Terra BORING LOG' -Associates', Inc. POINT EDWARDS.CONDO.MlNiUM'S EDMONS, WASHINGTON Consultants in Geotechnical Engineering Geology and Environmental Eartt� Sciences Proj.- No. T-4893 FDate JAN 2003, Figurd 7 Boring No. B-4 Logged by:, DPL ,Date: 12/16/02 Approximate Elev. 90 $oil Description Consistency/ Relative Depth E (N), Blows/ Moisture Content Density (ft.) Cz FILL (Old test pit): -bluish -gray silty sand, fine grained, wet, with a trace of wood particles. Appears disturbed. Loose 7 27 FILL (old test pit): mottled brown silty sand, fine grained, moist. ..Mediurn Dense 10. 17 21 31 FILL (Old test pit): brown silt and clay, moist, with a trace. of brown orqanic material. ----------------- ------------------------------- 7 ----------------------------------------------- Very stiff Bluish-gray SILT to CLAY, low td medium plasticity. Very 17 28 .(MUCL) stiff Gray SILT to CLAY, Moist, low to medium plasticity. (MUCL) ------------------- ------------------------------------------------------------------------ very, stiff 20 .30 23 LL = 35.5 PI = 1.1.5 Grayis ' h-brown sandy SILT to clayey SILT, fine grained, moist. (ML) With thin partings of iron -stained, fine- grained Very stiff 35 23. sand. Grayish -brown clayey SILT to silty CLAY, moist. (MUCL) With thin discontinuous lenses of gray to mottled gray _jinnrained sand. ------------------------------------------------ Very stiff I I . ----------------------- -30 - . . 3 0 24 . . . . Gray silty SAND, fine grained, moist. (SM) Dense 37 15 -------------------------------------------------------------------------------------- Gray sandy SILT to clayey SILT, fine grained, moist, low plasticity.. (MLto.MUCL) -------- Hard —40 3.4 11 7 Gray clayey SILT, moist, low plasticity. (MUCL) --------------------------- ------------- ------ Hard I ------------------- 37 20 Gray sandy SILT to silty SAND, fine grained, moist,, (MUSM) Dense 50. 312 19 4� 18 —60 42 15 Boring terminated at 61'.5 feet. No significant groundwater encountered. Terta BORING LOG. Associates, -Inc. POINT EDWARDS- CONDOMINIUMS EDMONDS,, WASH I NGTON consult6nts in Geo'technical Engineering Geology �nd Environmental Ea6 Sciences Proj. No. Date JAN 2003 Figur Boring No. B*5 togged,by: DPL. Date: 12/16/02 Approxirhate Elev. 105 Soil Description Consistency/. Relative Density Depth E't M U) (N) Blow's/ Moisture Content Brown to-g�ayish-brown silty SAND, fine grainedi wet,- with faint.mottling. (SM) ----------------------------------------------------------------------------- Medium Dense ---------------------- 1 19 Gr ay'S.ILT, medium to high plasticity, moist. (MH) -------------------------------------- -------------------------------------------- stiff --------- _1 0� 13 35 7 Gray CLAY'and SIJ, low plasticity, moist. (CUML) 7 7- very stiff 25 26 40 ------------------------------------------------- ----------------------------------------- -Gray silty SAND, fine grained, moist.to wet. (SM) ----------------------------------------------------------------------- ------- Dense I ------------- -------- —20 - 31 26, Gray CLAY, low plasticity, moist.. (CL) Very 22 27 stiff 42 Gray CLAY, low plasticity, moist. (CL)' very —30 .22, 25 2 --------------------------------------------- I ---------------------------- stiff -------------------------- Gray sandy SILT to silty SAND, fine grained, moist., Dense 46 25 (Musmy -------------------- ------------------------------------------------------------ Dense —40 43 115- Gray sandy SILT to, clayey SILT, non -plastic, moist. (MLtoMUCL), -------- 77 ------------- --------------------- ----------------------------------------------------- Dense 31 20 Gray sandy SILT to silty SAND, fine grained, dry to moist Dense —50 46 18 Moist to wet. -------- --------------------------------------------------------------- Medium Dense ------------------------ - 28 20 Brown silty SAND, finegrained,.moist. (SM) Very Dense 60 64 13' Boring ter miinated at 60.5 f * eet. No significant groundwater encountered. Terra Associait6s,- Inc., BORING LOG POINT EDWARDS CONDOMINIUMS EDMONDS, WASHINGTON Consultants in Ge6technical Engineering Geology and Environmental Earth Sciences' Proj. No. T-4893. Date JAN.2003 Figu Test Pit No'.'. TP-1- Logged by: JCS Approximate Elev. 104 Date: 10/ 18/01 Moisture Depth Content Soil Description (ft.) N 0— FILL: crushed rock surfacing over brown to gray silty sand to sandy silt, fine grained, firm, moist. ( WIVIL) Rusty brown silty SAND fine grained, medium dense, moist, with occasional fine gravel and fine roots. (�M) Gray to mottled gray silty SAND, fine grained, medium dense to dense, moist, with occasional fine gravel. (SM) 5— Becornes lig ht b rown at approximately 6 feet. 26 10— Gray CLAY, hard, moist, massive. (CL) PP 4.5+ tonstfe LL= 35.8 PI 15 15,1 Test pit terminated at 14 feet. No groundwat,erseepagp.. 20 Test -Pit No. TP'2* Logged by: JCS Approximate Elev. 124 Date: 10/18/01 Moistuee Depth Conte nt- Soil Description N 0— FILL: crushed rock surfacin ove r brown silty sand to sandy silt, fine grained, firm, moist. 4-inch thick organic Payer at base. (SM/ML) � (Old topsoil horizon) - Brown silty SAND, fine grained, medium dense, moist. (SM) - Mottled' rayish-brown silty SAND, fine grained, medium dense, moist. '2 6, 9 (SM) 5- - Grayish -brown silty SAND, fine grained,. r-hedium dense to dense, moist. - (SM) 10— Gray CLAY,'hard, moist, laminated with light gray silt partings. (CL) Pp 4.5� tons/ft' 37 15- test pit terminated at 14 feet. - No groundwater seepage. 20 � I TEST PIT LOGS Terra POINT EDWARDS. CONDOMINIUMS EDMONDS, WASHINGTON Associates, Inc Geotechnical Consultants Proj. No. T-4893 I' Date JAN 2003] Figure i n Test Pit No. TP-3 Logged by: JCS ApproximateElev.1 21 Date: 10/18/01 De'th' Moisture p Content (ft.) Soil.Description N 0— FILL: brown silty sand, fine grained, firm, moist, with occasional fine gravel and organic material. (SM) (Hydrocarbon odor) ilty SA Dark brown an ND, fine grained, soft, moist to wet. (OL) org izo 'c)s (Old topsoil hor n �15 5— Tan to light gray silty CLAY to clayey SILT, hard, moist. (CUML) (Hydrocarbon odor) 10— . Gray CLAY, hard, moist, laminated -with partings of light gray silt and gray - fine sand. (CL) Pp,= 4.5+ 32 tonsife - Test pit terminated at 13 feet. 15— Light, groundwater seepage from Ooin.t source at 4.5 feet. 20 Test Pit No. TP-4 Logged by: JCS, Approximate Elev. 92. Date:. 10/18/01 Depth Moisture Content Soil Description N 0— FILL: light brown silty sand e gra irm, dry to moist. (SIVI) 2-inch thick olafin organic layer at base. topsoil =n) Light brown to t - an silty SAND, fine grained,, medium dense to dense, dry. (SM) 5 Mottled grayish -brown silty SAND,'fine g rained, medium dense'to dense, 29 moist. (SM) LL = 42.7 Light grayish -brown to light brown * CLAY and SIJ, hard, moist, lami.nated' 29 PI = 19.7 with partings of dark.gray fine sand. (CUML), Pp = 4.5+ tonsife 10— Gray CLAY, hard,, moist. (CL) Pp = 4.5+ 29 tons/fe - Test pit terminated at 13 feet. 15— Tracegroundwat6r.seepage at 6 feet. ,20 TEST PIT LOGS Terra POINT EDWARDS CONDOMINIUMS EDMONDS; WASHINGTON Associates, Inc. Geotechnical Consultants Proj. No. T-14893- I Date JAN 2003 Figure 11 Test Pit No. TP-Z, Logged by: JCS Approximate Elev. 110 Date:10/18/01 Depth Moisture (�ontent Soil Description 0— 6 inches.DUFF and TOPSOIL Lighi brown SAND with silt to silty SAND, fine grained, medium dense, moist. (SP-SM/SM) 23 5— Mottled grayish-browri SAND to'SAND with silt', fin'e,grained, medium dense to dense, moist. (SP/SP-SM) Becomes wet.at approximately 9 feet., 26 10 34 LL = 44.5 - G�ayish-brown to gray CLAY, hard,moist, generally massive, With.' PI = 21.3 - occasional thin laminationslof gray silt. (CL.) Pp =A 5+ tonis�� 15 Test pit terminated at 16 feet. Light groundwater seepage between 9 and. 10. feet. 20— Test, Pit, No.'-TP-6 Logged by: JCS Approximate Elev., 150 Date: 10/18/01 Moisture Depth Content Soil Description N 0— FILL: brown to grayish -brown SILT, CLAY, and fine grained SAND, firm' moist to wet, with some fine gravel and occasional organic.material. 32 5— . FILL: gray to brownish gray silt, clay, and fine grained sand, firm, moist to - wet, with moderate organic material (including wood. debris) and some gravel. 12-inch thick organic layer at base. (Old topsoil horizon) 10— Gray silty SAND to sandy SILT, fine grained, dense,. moist, with occasional fine to coarse gravel. (SM/ML) (Glacial till -like), - Test pit terminated at 16 feet. - No groundwater seepage. 20 TEST -PIT LOGS Terra, POINT EDWARDS CONDOMINIUMS EDMONDS, wAsHINGTON Associates, Inc-.. Geotechnical Consultants Proj. No. T-48937 Date JAN'2003+ Figure 12 jest Pit No.-70-7 Logged by: JCS Approximate Elev. 121 Date:1 0/18/01 Moisture Depth Content (ft.) Soil Description N FILL: dark brown organic silty sand, fine grained,' firm, moist. Mottled gray to brown SAND with silt to silty SAND, fine grained, medium dense to dense, moist. (SP-SWSM) (Hydrocarbon odor),' 20 Tan to light grayisMrown, silty CLAY to CLAYha�d, moist, occasional 24. mottling. '(CL) Pp - 4.5+ tons/fe 31 Test pit terminated at 15 feet. No groundwater seepage. Test Plt No, TP-8* Logged by' JCS A'proximate Elev. 121 p Date: 10/18/01' Moisture Depth Content Soil,Description . %) 0.- FILL: light brown to gray silty sand, firm, moist tolwet,'with organics. FILL: dark brown organic silty sand, loose, wet, with significant wood debris (timbers and branches). 2.5-foot diameter boulder. Gray. SILT to SILT with sand, fine grained, dense, moist to wet. (ML) .25 Light grayi�h-brown to tan sandy SILT, fine grained, very dense, moist, ��ith occasional.firie gravel. (ML) (Glacial till -like) 16 'Test pit terminated at 15 feet. Light groUndwater seepage at 6 feet. 20 7 TEST'PIT LOGS POINT.EDWARDS CONDOMINIUMS EDMONDS, WASHINGTON Associates, lnc.� Geotechnical Consultants 3. Date JAN 2003' Proj. No.7-489 Figure 13 Logged by -JCS Date: 10/18/01 Depth (ft.) .0 5 10 15 20 Test Pit No. TP-9 Approximale Elev. 150 Moisture Content Soil Description (%) - FILL: crushed rock surfacing over I grayish -brown sandy silt and clay, firm, - moist. 6-inch thick organic layer at base. (Old topsoil horizon) Mottled grayish -brown sandy SILT to sandy CLAY, stiff, moist: (MUCL) Pp 4.5+ 30 tonsfie 37- Grayish-brown CLAY, hard, moist, massive. (CH) LL = 58.8 P1 = 30.1 Gray SILT and CLAY, hard, moist, with occasional laminations of gray. Pp = 4.5+ fine sand. (MUCL) 1 22 1 tons/fe Test.pit terminated at 15 feet. No groundwater seepage. Logged by: JCS ,Date: 10/18/01 Depth 0- 5 1C Test Pit No. TP-10 Approximate Elev. 157* Moisture Content Soil Description (%) 6 inches DUFF and TOPSOIL. Brown sandy SILT, fine grained, medium dense, moist. (ML) 40 Grayish -brown SILT and CLAY, hard,, moist. (MUCL) Pp 4.5+ tonsife 34 Gray SILT and CLAY, hard, moist. (MUCL) Test pit terminated at 15 fleet. No groundwater seepage. 20— TEST PIT LOGS. Ter' ra -,POINT, EDWARDS CONDOMINIUMS Associates, Inc. EDMONDS, WASHINGTON Geotechnical Consultants Proj. No. T-4893 Date JAN 2003 1 Figure 14 7 Test Pit No. TP-1 1 Logged by: JCS Approximate Elev. 78 Date, 10/18/01 'Moisture, Depth' Soil Description Content 0— N 5 10 15 20 7 Mottled grayish -brown SAND to SAND with silt, fine gr ained, medium, dense, moist to wet. (SP/SP-SM). 25 15 - Light brown silty SAND to sandy SILT, fine grained, medium dense to - dense, moist. (SM/ML) Increasing silt with ddpth.- 22 Test pit terminated at 15 feet. No groundwater seepage. Logged by: JCS Date: 10/ 18/01 Depth (ft.) U 5 10 2C Test, Pit -No. TP-1 2 Approximate Eley. 76 Moisture .Soil Description Cdnfent 6 inches crushed rock surfacing. Mottled gra ish-brown SAND, fine to medium'grained, medium dense, moist, with � na, occaqin ne gravel. (SP) (Hydrocarbon odor) Gray SAND with silt to SAND'fine grained, medium dense to dense, 17 moist to wet., with occasional fine to coarse gravel. (,SP-SWSP) 15 Mottled grayish -brown silty SAND with gravel to sandy'SILT with gravel, fine sand, fine gravel, dense to verydense, moist. (SM/ML) (Glacial till -like. between 8 and 10 feet) Increasing gravel with depth..' 20 Test pit terminated at 15 feet.' Trace groundwater seepage at 8 feet'. TEST PIT LOGS', Terra POINT EDWARDS CONDOMINIUMS EDMONDS, WASH I NGTON Associates, inc., Geotechnical Consultants Proj.No.T-4893 I DateJAN2QO3 Figure,15, Test Pit No. TP-13 Logged by.* JCS Approximate Elev. 86 Date: 10/18/01 Moisture Depth So . il Descri ption Content N 07 12 inches crushed rock surfacing.. Mottled grgoish-brown silty SAND to sandy SILT, very dense, moist. (SM/ML) 25. (Hyd ocar n odor) 31 5— Bluish-dray CLAY, hard, moist,'with partings of gray fine sand and light gray silt. (CL) Pp'= 4.5+ tonsife 10- 15— Test pit terminated at 14 feet. Trace groundwater seepage at 2.5 feet.. 20 TPI Test Pit N o.: -14 Logged by: JCS Approximate Elev. 76 Date: 10/18/01 Moisture Depth Content (ft.) Soil Description N 15 FILL: bluish -gray silty sand with gravel to sandy silt with gravel, fine sand, line gravel, rhediurn dense to dense, moist. (SM/ML) 10 Light brown sandy SILT, fine grained, dense, moist,'with occasional fine gravel and thin layers of fine grained silty sand., (ML) 19 15 Test pit terminated at 15 feet. No groundwater seepage. 20 TEST PIT LOGS Terra POINT EDWARDS- CONDOMINIUMS EDMONDS' WASHINGTON Associates, Geotechnical Consultants Proj.. No. T4893 bate JAN 2003 Figure 16 Logged by: JCS Date! 10/18/01 Depth (ft 0 5 10 15 Test Pit -No. `TP-1 5. ate Approximc Elev. 86 Moisture Content Soil Description FILL: graysi(I sand to sandy silt, line grained, medium dense, moist with occasional fine g WIVIL) rave Dark brown organic sandy SILT, fine grained, firm, moist, with occasional roots. (OL) (Old topsoil horizon) Mottled grayish -brown silty SAND with gravel to SAND with silt and gravel, fine sand, fine to coarse gravel, medium *dense to dense, moist. 10 (sm/sp-sm) Becomes brownish -gray and moist to wet at approximately 8 feet. V - Brownish -gray -silty SAND with gravel to sandy.SILT with gravel,� fine sand, - fine, gravel, dense, moist. (.SWML) Plaicial till -like) 18 Test pit terminated at 1 ' 5 fbet.- Trace groundwater seepage at 11 feet. 20— Test Pit No. TP-1 6 Logged by: JCS Approximate Elev. 68 Date: 10/18/01 Depth Moisture.. Content Soil Description 0- - FILL: gray to brown silty sand with gravel, fine grained" firm to loose, - moist to wet. (SM) 5— FILL: grayish -brown silty sand with gravel, fine grained, firm, moist to wet, with significant organic soils and wood debris. 23, 10— 16 Bluis;h-gray sil SAND with qravel to sandy SILT with gravel, fine sand, fine gravel,, dens WIVI/ML) (Gracialtill-like) Light brown SAND, fine grained, medium dense to dense, rhoist.'.(SP) 15 Test pit terminated at 13 feet. 15 No groundwater seepage. 20. 7 TEST PIT, LOGS' Terra POINT EDWARDS CONDOMINIUMS L EDMONDS,WASHINGTON Associates,.Inc., Geotechnical Consultants Date JAN 2003 Figure -4893 Proj. No. T. Test Pit -No. TP-1 7. Logged by, JCS Approximate Elev. 82 Date: .10/18/01 Moisture Depth Content Soil Description N 0— R brown silty SAND with gravel, fine sand, fine to coarse gravel, usty - medium dense. moist. (SM) tySAND with gravel, fi—ne sand, fine Mottled grayish -brown sil to coarse gravel, medium dense to dense, moist. (SM) 13 Grayish -brown silty SAND'with gravel to sandy SILT with gravel, fine sand, 5 fine to coarse gravel, dense to very dense, moist. (SWIVIQ (Glacial till -like) Sand content increases with depth., 10 - Test pit terminated at 9.5 feet. . No groundwater seepage. 15- 20 TEST PIT LOGS Terra POINT EDWARDS CONDOMINIUMS EDMONDS, WASHINGTON' Associates, Inc. Geotechnical Consultants Proj. No. T-4893 � Date JAN 2003 Fig'ure N1, TERRA ASSOCIATES, Inc... a. A ALL 4 A 'C nsultint'inGeo techni . c al Engineering, . Geolog . y &A 0 a s and Environmental Earth Sciences: Septqmber-6,2005 Prcject No. T4893 Mr. Ross. Woods Point Edwards, LLC 2801 Alaskin Way, Suite 107 SEP 6 2005 Seattle, Washington 98121 2UILOING DEPARTMENT r,,.Ty OF EDMONDS Subject Response to'Pla*n -Review Comments - Building 5 Foundation Point Edwards Condominiums Edmonds, Washington References: L. Letter, C ity of Edmonds Building Division Plan Review Comments, Point Edwards Building 5 Foundation Only, Plan Check #05-335, dated August 23, 2005 .2.. Preliminary Geotechnical Report; UNOCAL Site, Project No. T4893, prepared by Terra Associates, Inc., dated November 21, 2001 .3.: Geologically Hazardous Areas Review, Point Edwards.Condominiums (UNOCAL Site), Project No. T4893, prepared by Terra Associates, Inc., dated January 20, 2003 4.- Supplementary Subsurface Exploration, Point Edwards Condominiums, Project No. T-4893, prepared by Terra Associates, Inc.; dated July 30, 2003 5. Geologically FIA 7A 'doll Areas Review,- Proposed Building 5 Expansion, Point Edwards Condominiums, Project No.-T-4893, prepared by Terra Associates, Inc., dated.June 24, 2005 6. Let.terSeisinic Wall Pressure and Pile' Point -of -Fixity —Building 5, Point Edwards Condominiums,.Project No. T-4893, prepared by Terra Associates, Inc., dated September 1, 2005 Dear W. Woods: As requested by Mr. Jeff Brink of DCI Engineers, we reviewed City of Echnonds; comments regarding the City's review of foundation plans- for Building 5 at the. Point Edwards condominium project. Specifically, we have. been asked to respond to comments No. 9 and No. 10 on Page 2, and comment No. 4 on Page 3 of the referenced letter. 12525 Willows Road, Suite. 101, Kirkland, Washington Phone (425) 821-7777 * Fax (425) 821-4334 Mr. Ross Woods September 6, 2005 Comment No. 9, Page 2: Provide a letterfrom the geotechnical engineer of record that he has reviewed the building plansfor Building 5 andfinds them consistent with the recommendations in his report and supplemental letters. We reviewed structural drawings for Building 5 to verify that the plans conform to our geotechnical recommendations. We were provided the following plans for our review: * Structural Sheets SLI through S6.3, prepared by DO Engineers, dated August 10, 2005 The plans indicate foundation support for Building 5 will be provided by conventional spread footings except for the northern side of the building, which will be supported by a deep foundation system consisting of augercast piles and grade beams. Based on our review of the drawings provided to us, it is our opinion that the plans we reviewed are in general conformance with our geotechnical recommendations. However, we noted the following discrepancies or omissions during our review: Sheet SLI: Design soil values given in the Soils and Foundations section of the Structural General Notes indicates that structural design used an allowable foundation pressure of 5,000 pounds per square foot (psf). The note titled Slabs -on -Grade and Foundations states the following: "All foundations shall bear on structural compacted fill or competent native soil per the geotechnical report." Based on our review, it does not appear that foundations for Building 5 will be constructed on structural fill; however, as discussed in our referenced preliminary geotechnical report, foundations supported by structural fill should be dimensioned for a net allowable bearing capacity of 3,000 psf. Comment No. 10, Pa2e 2: Yhe Engineering Division has informed me that the site for Building 5 was used as a water collection area. Please have the geotechnical engineer verify that this does not affect the recommendations in his soils reports and supplemental letters. The temporary excavation for Building 5 has been exposed to weather for about one year. Water from direct precipitation and surface runoff from adjacent areas collected in the excavation due to the relatively impermeable nature of the transitional bed silt and clay soils exposed throughout the bottom and sides of the excavation. Due to the relatively impermeable nature of the dense to very dense native soils, the water that collected in the excavation only affected the exposed soils superficially. Considering this, it is our opinion that the presence of the water in the existing temporary excavation has not adversely affected the native soils underlying the upper few inches of the excavation bottom, and our previous geotechnical recommendations still apply. Comment No. 4, Paee 3: I am not sure if the following information is specified in the other report stated by the engineer, but they are needed in a report in order to complete the reviewfor the engineer's assumptions: a. The active andpassive pressures associates with the retaining wall design. Project No. T4893 Page No. 2 Mr. Ross Woods September 6, 2005 Earth pressures used for structural design are given in Section 5.4 and 5.5 of the referenced preliminary geotechnical report, dated November 21, 2001, and on Figure 15 (Earth Pressure Diagram -Basement Walls) in the referenced geotechnical report, dated July 30, 2003. b. A determinationfor the active lateral pressures on the retaining walls due to earthquake motion. We recommended using a uniform, horizontally -applied seismic earth pressure value of 17H psf, where H is the height of the wall in feet. This value is documented in our referenced letter, dated September 1, 2005. C. 7he 'flerural length" of the piles has to be established so that the pile is able to resist the lateral movement and relay it to the earth. For the existing site soils, an 18-inch diameter augercast pile having a minimum pile length of 15 feet, and assuming a free -head condition at the top of the pile, analysis yields a point -of -fixity (depth to zero pile shear) located at a depth of 5 feet below the top of the pile. This is documented in our referenced letter, dated September 1,2005. d. The engineer did include an excerpt from the November 21, 2001 report, but this should be updated to ensure it is still consistent with the actual site conditions especially for length since the flexural length will control design. Recommendations for pile design presented in the referenced geotechnical report, dated November 21, 2001, remain valid for existing conditions. e. Yhe augercast pile lengths are not specified on the plans and are subject tofteld "tests " according to the note under "SIZE" on Sheet 1. 1. 7he soils engineer is supposed to determine this length, but theflexural length will surely control over the vertical load capacity determined by such tests. The recommended minimum pile length is 15 feet, with a minimum 5 feet of pile penetration into the native bearing stratum. f If the augercast piles exceed 45 feet in length, then the design and installation has to be directly supervised by a registered engineer knowledgeable in thefield ofsoil mechanics andpilefoundations, the proofofwhich should be given to you before hand. The recommended minimum pile length is 15 feet. We do not expect that actual pile lengths will significantly exceed this length, and certainly will not exceed 45 feet in length. 9- Yhe Certified Geologist need to indicate how deep the footings have to (be) below grade on the down - slope side to the west of the piles so at (sic) not to cause sloughing or other localized.failures of the adjacent slopes there. Planned grading between the expanded southwestern portion of Building 5 and the top of the slope will create a flat yard area at Elev. 86, and will result in a modified top -of -slope that is located at least 25 feet from the building. Considering this setback distance, the conventional spread footing foundations located west of the piles can be constructed on competent native soils at the minimum depths recommended in the referenced geotechnical report, dated November 21, 2005. Project No. T4893 Page No. 3 Mr. Ross Woods September 6, 2005 We trust the information presented is sufficient for your current needs. If you have any questions or require additional information, please call. - Sincerely yours, TERRA ASSOCIATES, INC. JUS/1W* om cc: Mr. Jeff Brink, DCI Engineers Project No. T-4893 Page No. 4 1C. S T ­4 93 8 -1801 Al"Imn*WA�,'Suite'-10.- -SUILOING DEPARTMEN't c §,j�uth iili��` 5- ..S* int- .,renv a a !Df. U1 .0raly t..dwar4 Qi4d;�� s, Zo.r�okd Was gton te Pojort 11felini'm''Ai-y Gcoii�phnical Repoit., UO �4843;prep�md �y T eim'' Aislocivitca Tnc.,0Ait4-Nov 'i 2.1' '200-V'-*-`1.' Stdip Sl6pe'Hatz*4-:R6,�iM Mut Edwaids Condoid p (UNOCALSit�),;. murn. proj 61pt 'i,prep Aiso9atea,'Ibc TA993'. ked-W,"rei-W. dit , ip'dJ)'4r_*bcT -13,200-2 (UNOCAI�Si*Y; dawdIgnuml TM 'T�4893,­ ' T�" o;ciiiiSI-,b6.:;,.� . � -A�ji kovi6W hbpo id,B"di:bg'5-,EV hOon .Point Edwards". Ait6d 2 tf9rivimm; .,.qj�c - T-4 9 pr"e4�yy erraAssociitisI�c.,'j, -`A�ii 24; 0 Dear W.* Woods: ttic 5m jeu�.zu s1bpeAnclination& f& soil �'cdn6tiW- on. cm.; As. ieqii6j!rd,w.e x d 14 k0proprh ..0 4miixh projept, ur,cm tion'Is.., OmU i*b dus -c6uditicins owprevOuA exp OAS, in..the ari Qf B-Aildift9, OuilUentbiRe ...based ea* 5' -, Aing braky : out in the-v . icivaty .9 cNis 9 -'OF IS-: to .20- oot,`Iii$h't*p an tirr t�� avds '-shou'm". ca� a Nan �11* iLd * Asis'6cdates, xkteo, 4�ms�,2-211 titled B av*�6g:tross.� Y.Tri 005.,,, X'I si& -of- 9oiIC'cxp6idd'it die cxi4fih -'apj� g mporwy CM t..JiWdiixj�S-ai� dojiii@k� A, `t*L=,tioimIbed:db -6�iwcomi�"�Of -deh:9LA6*v.crydcmc �01 iaikd 6d �c ' 1hpkta6 BuiWing:*S.; - e 76h epogi%� me Abat-W been ft�iQ wiih -AdIni au'st., (C=J.`� 1�0-:6�igtifig Ternodrtry cu s 6pe. �zs !�xrAmed a e'At this- �f ti� el. t6tla�`iindcFp're. huitiori-.fc�: ovee dric yr#_ W�. ob ih fib sezvW.s6,v&aiaivAs,.qn e bin OPC shall6w &6slo"h Or". gfilirficiai-* iIdVgyhfiI0:.hOwcvpr_,�th� itoat�d fiviln'li�06nti6116,drlinoff V anfico v4tcr .:-,arpasup dTic`n­t-"rn-t6'�ut_ 'id t tt, ih' '­itiop4'b�d c ay can !�.s op. 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