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Plan Check #: 20080117
City of Edmonds
Plan Review Corrections
Date: March 148 2008
Project Name/Address: Hillard @ 15515 76t" Place W
Contact Person/Address/Fax: sbarnes@cornerstonearch.com
Permit Coordinator: Marie Harrison 425.771.0220 x 1389 Department: Building
The following City of Edmonds departments have reviewed your application:
[ Building Department [ ] Recycling
[ ] Planning Department %��j� f,� [ ] Pretreatment
Engineering Department Jei )CZ96e40 [ ] Water Quality
[�] Fire Department
Attached are comments and corrections from the appropriate departments. Please respond to
all comments and corrections and resubmit your corrections to all departments
at one time. Please bubble your corrections and submit three sets of
corrected sheets. No partial resubmittals will be accepted.
Thank you,
Senior Permit Coordinator
425.771.0220 x 1389
harrison(a@ci.edmonds.wa.us
DATE FAXED ! (Attach fax transmittal Page—[ of LIY
LITem p/DSTIForms/plan-review9101
of EDS City of Edmonds
PLAN REVIEW COMMENTS
BUILDING DIVISION
est. is9� (425) 771-0220
DATE: March 12, 2008
TO: Steve Barnes, AIA
FROM: Jenny Readwin, Plans Examin
RE: Plan Check # BLD20080117
Project: Hilliard SFR
Project Address: 15515 75h Place West
During review of the above noted ESLHA application, it was found that the following information,
corrections, or clarifications are needed. Please resubmit three (3) copies of revised sheets and/or
documents with a written response to each of the items below to the Permit Coordinator assigned to
your project:
1) The City copy of all plan sets must be wet signed by the applicable design professional. For
plan sheets currently on file at the City that will not change during the review process please
instruct the design professional to come to City Hall and wet sign over the stamp.
2) In general the site plan must match the civils (preferred scale 1-20). Please add the following
information to the site plan.
■ Add vacated 73`a Ave West and undeveloped 156th St SW
■ Clearly indicate all proposed debris walls, soldier pile walls, etc.
■ Provide top and bottom wall elevations for all proposed soldier pile, retaining walls,
stair/walk walls, driveway retaining walls, (note that all wall designs shall be supplemented
with supporting calculations, etc.)
■ Label all cantilevered features, covered porches, decks, etc. and indicate setback distances to
property lines
■ City code requires that height be taken from the smallest rectangle that encompasses all four
corners of the house. Note when to include eaves. Be sure to include the metal coping
shown on the building section views of Sheet A4.L When a corner extends across property
lines use the average of the two points as they cross the property line. Please refer to City
Height Handout and recalculate height.
■ Indicate the datum point (benchmark) used for height calculations
Resubmit three (3) new site plans scaled and one additional reduced site plan on paper no larger
than 8 %" x 14".
3) Note the 2006 edition of codes.
4) Call out square footages for each floor, include deck area.
5) Sheet A3.2 missing from plan sets.
6) Note that the fire sprinkler system is a deferred submittal (City requires 3 weeks processing
time). A DCDV shall be required to be installed in a vault at the property line show on civil
plans (see City Engineering webpage for vault and detector detail and add to plans).
7) Alter #17 glazing u value on Sheet A2.1 (note Energy Code Option III is not available to R3
occupancies suggest that you use option IV).
8) Which fan is the whole house fan? What cfm? Indicate on pians.
9) Complete the last page of the energy worksheet.
10) Alter #10, wall height is 72" minimum on Sheet A2.1.
11) Call out garage door to entry and exercise room door (solid core 13/8" or 20 min fire rated).
12) Indicate if lower storage and exercise rooms will be heated or unheated. If heated R21 wall
insulation required and underslab R10.
13) Provide boiler specifications.
14) For in -floor hydronic heating verify additional dead load for floor joists has been accounted for.
15) Boiler shall be provided with RPBA to separate boiler from domestic water system.
16) Provide combustion air calculations for boiler.
17) Show handrail on interior stairs.
18) Show required stair illumination.
19) Specify deck fireplace on Sheet A2.2 (provide specs for exterior installation).
20) Provide typical deck guard detail.
21) Provide typical exterior stair detail.
22) Specify all glazing required to be safety glazed.
23) Provide smoke alarm in outside hall of sleeping rooms.
24) Unless a door is provided, indicate which window in each sleeping room is the egress window.
25) Provide guard detail at second floor hall to great room below. Also, guardrails are required to
resist 200 psf and the in -fill components must resist 50 psf per Table R301.5. Note on plans.
26) Show how island sink will be vented through the roof or with a loop vent as permitted by UPC
909.0. Air admittance valves are not permitted unless first approved by the Building Official
under a formal alternate design request per UPC 301.2 (additional fee required).
27) Provide crawlspace ventilation calculations according to R408.1 (1 square foot for every 150
square feet of crawlspace area) and show size and location of crawlspace vents on foundation
plan (area by exercise room).
28) Show size and location of attic access (Minimum 22" x 30").
29) Provide attic ventilation calculations (at 8:12 area) according to R806.2 (1 square foot for every
300 square feet of attic space if using both eave and ridge vents and 1 square foot for every 150
square feet if not).
30) Provide attic access at 8:12 area (22" x 30").
31) Note all wood exposed to weather shall be pressure treated or naturally resistant to decay.
32) Add to typical stair detail handrail, guardrail, headroom etc. complying with R311.5.
33) It appears that there will be a site built showers. Provide shower pan construction detail
including materials, drain, slope, etc.
34) Indicate note on fireblocking requirements for furred walls per IRC 602.8.
35) Specify on the elevation views where the grades slope away from the building. If minimum 6"
within 10' is not possible or habitable or useable space is below grade, foundation drainage is
required. Provide footing drain detail on foundation sections complying with R405.1 and the
soils report and show required drain locations on the foundation plan.
36) Retaining walls located in a critical area must have plans designed consistent with ECDC
Chapter 23.80 (including design calculations) and stamped by a Washington State Licensed
Professional Engineer. The City requires peer review and special inspections for all retaining
walls in critical areas or their buffers.
Page 2 of 3
37) Shoring (temporary and/or permanent) appears to be required. Provide details and a separate
site plan showing locations of the temporary or permanent shoring walls.
38) Special inspections are required for this project and must be clearly noted on the plans.
Complete the enclosed special inspection agreement (note the form must be signed by the
owner, the general contractor and the special inspector and submit to the City for approval prior
to issuance).
39) The North Edmonds ESLHA Map shows the lot incorrectly sited, please correct the copies on
file at City Hall.
40) See attached structural comments from city consultant. Respond to each item in writing.
Resubmit structural calculations for all proposed soldier pile and debris walls and clearly note
on the foundation plans which walls are debris walls. Note S 1 calls out 2003 the City has
adopted the 2006 I Codes plans shall be updated to current code.
41) See attached ESLHA geotechnical comments from city consultant. Respond to each item in
writing. Is the Cornerstone Geotechnical supplement letter dated 2/8108 intended to meet the
Geotechnical Hazard Identification/Declaration & Mitigation Statement of Risk? If so the letter
is lacking key language (see attached) and note that the letter must be signed by the Geotech and
Civil Engineers of Record.
42) Prior to permit issuance the following shall be required:
a. Contractor information, State and City business license
b. Contractor public liability insurance form with City as named additional insured (one
million dollars minimum)
c. Site Restoration Bond (amount to be determined by City Engineer) contact your Permit
Coordinator for the bond forms
d. Special Inspection and Testing Agreement form signed by all parties
e. Outstanding peer review and plan review/permit fees associated with the permit
f. Fees to record the Hold Harmless Agreement
g. City copy of all plans wet signed by applicable design professional
h. After the permit is issued the owner must submit an affidavit of permit issuance
Page 3 of 3
9. STRUCTURAL CALCULATIONS Two Copies
Provide two stamped and signed copies of structural design calculations that correspond with all
structural details as shown on the building plants_ Include calculations for all temporary and permanent
shoring, retaining walls, catchment walls, etc_
10. LEAD DESIGN PROFESSIONAL DESIGNATION AND STATEMENT Three Coles
One design professional shall act as the "lead design professional" for the applicant during the entire
permit review process. This licensed professional is responsible for coordinating and incorporating (/I
recommendations of other design professionals onto the plans or into the submittal packet, This person
shall submit a stamped letter or make a notation on the face of the plans stating the following:
• That s/he has reviewed the geotechnical report, understands its' recommendations and
have incorporated into the design the established measures to reduce the potential risk of
injury or damage from any earth movement predicted in the report.
11. APPLICANT/OWNER LIABILITY & LANDSLIDE ACKNOWLEDGMENT
Three Copies (d
The applicant/owner of the site shall submit a signed and notarized statement that includes the
following language:
That the accuracy of all permit submittal information is warranted by the
applicant/owner in a form which relieves the City and its staff from any liability
associated with reliance on such permit application submittals.
• While an application may reference the reports of prior public consultants to the City, all
conclusions shall be those of the applicaut/owner and her/his design professionals.
• That the applicant/owner understands and accepts the risk of developing in an area with
potential unstable soils and understands the required temporary and permanent erosion
control and site maintenance issues associated with specific geologic hazards or conditions
of the site that may affect slope stability over time.
• That they will advise, in writing, any prospective purchasers of the site, or any
prospective lessees of structures on the site, of the slide potential and on-going
maintenance issues of the area and on the property.
12. GEOTECHNICAL HAZARD IDENTIFICATION/DECLARATION & MITIGATION
STATEMENT OF RISK FROM GEOTECHNICAL ENGINEER AND CIVIL
ENGINEER OF RECORD Three Co les
The Geotechnical Engineer of Record and Civil Engineer shall provide a disclosure letter (stamped and
signed) addressing the provisions of ECDC 23.80 for geologically hazardous areas. The letter shall
include the following language:
v_T[t.Fs\MEnoow\Est HA20o7_noca/2ro7 page 7
In her/his judgment the plans and specifications prepared by the structural engineer
conform to the recommendations in the geotechnical report.
That the risk of damage to the proposed development, or to adjacent properties, from soil
instability will be minimized subject to the conditions set forth in the report and that the
proposed development will not increase the potential for soil movement. Minimized shall
mean that the applicant has utilized best available science andcommonly accepted
engineering and architectural practice to minimize, to the extent possible, the risks
associated with development of the property.
• The statement shall include, as a condition, an evaluation setting forth the statistical
probability (percentage) of earth movement within a 25 year period, the susceptibility of
the risk, or hazard to correction, by on-site improvements and the measures taken to
mitigate the risk or hazard.
• The geotechnical engineer shall review the erosion and sediment control plan and provide
a statement about the adequacy of the plan with respect to site conditions and report
findings.
• From the guidelines in the 2007 Landau Summary Report; an identification of landslide
hazards applicable to the site, the on-site measures taken to correct or reduce the hazards,
as applicable, and, measures taken to mitigate potential impacts from the remaining
hazards.
• For sites where the hazards are not mitigated or where the risks from deep-seated or
large-scale earth movement cannot be practically reduced by individual lot owners, the
statement shall identify what hazards could not be addressed by individual lot
development. The statement shall specify any risks from earth movement that are not
fully mitigated by design measures and render an opinion as to whether the site will be
stable within the meaning of the ordinance following installation of all proposed
improvements.
Further recommendations, signed and sealed by the geotechnical engineer, shall be provided should
there be additions or exceptions to the original recommendations based on the plans, site conditions or
other supporting data.
13. STRUCTURAL ENGINEER DECLARATION Three Co les
The structural engineer of record shall submit a disclosure letter or include a notation on the. desi
drawings that includes the following language: > ;
• That he/she has reviewed the geotechnical reports, understands its recomxiie�tations,;6as.
explained or has had explained to the owner the risk of loss due to slides on"'.the site.
• That he/she has incorporated into the design the recommendations of the re ort > �
P
established measures to reduce the potential risk of in u bar , *
P l ry .or damage #hat.
caused by any earth movement predicted in the report_}
V_ HLEStMEADOVA sLHA 007.DOC4/2107 Page 8
Eagle Eye Consulting Engineers, P.S.
PO Box 523
Olalla, WA 98359
hoytjeter@centurytel.net
360 874 0562
Fax 360 874 0591
To: Marie Harrison
121 5th Ave. N.
Edmonds, WA 98020
Re: Hillard Residence
15515 75th Place West
Edmonds, WA 98020
Plan Review # 2008-0117 EECE # EDM 08-12
Plan review number 01
Structure
Area S.F.
Lower floor
614
First floor
2156
Second floor
1431
Total
4201
Garage
1181
Total
5382
Deck first floor
-405
rand total
5787
The above referenced project is in the process of plan review for compliance with
Edmonds ordinances and applicable codes. The following comments,
deficiencies/corrections must be addressed prior to completion of plans review and
subsequent issuance of permits.
Provide revised plans and calculations along with a written response to each of the items
listed below to facilitate a shorter back -check time.
SCOPE OF REVIEW
The scope of this review is for the Structural Only requirements of this project.
All features were checked only to the extent allowed by the submittals provided. All
portions of this project are assumed to meet or will meet other departmental requirements,
conditions and concerns before permit approval.
Page 2of5
Plan Review Number 01
EECE#: EDM 08-12
Hillard Residence
2008-0117
Structural Comments
General
1. The design analysis states analysis is per ASCE 7-02. This is not the adopted code
at this time. Please modify the analysis and drawings to meet the ASCE 7-05 as
required. Per check analysis it appears the design forces used are greater then the
required per ASCE 7-05/113C 2006. Please justify upon response and modify
accordingly.
2. Geotechnical report gives the design parameter for the 2003 IBC and not the 2006.
Please modify accordingly to the adopted code.
3. The supplement report for this single fancily home recommends soldier pile shall
be used on the northwest corner of the buildings. Drawings do not reflect this.
Please modify accordingly and submit analysis to justify. Cornerstone
Geotechnical supplement letter dated 2/8/08.
4. The geotechnical report state construction observations shall be performed by the
geotechnical engineers. Please coordinated accordingly and note this on the
drawings.
5. Engineer of Record (EOR), please clarify which retaining wall the analysis is for
that is noted Exercise Room w/Slid- Dec -07. The reaction at the top is 3.1 kips
and the bottom 5.5 kips. I was unable to determine from the drawing these
locations and the required detail in order to check if the connections will support
these loads. Please modify the drawings and submit analysis for these reactions to
be resolved.
6. EOR, it was not clear where the information from the analysis for the Exercise
Room W/ Slide -Dec -07 is at. The wall is 9" thick and it is not clear where this is
located. Please clarify upon response.
7. EOR, Please clarify the locations of the Exercise retaining wall w/EQ-Dec 07 is
located. The wall is required to be 9" but the wall shown is specified to be 8" on
sheet S2. Please clarify upon the responding.
Sheet S 1: Structural Notes
8. Please modify the general notes to the adopted code at this time. The adopted code
is the 2006 international building code as amended by the state of Washington not
the 2003 versions_
Page 3 of 5
Plan Review Number 01
EECE#: EDM 08-12
Hillard Residence
2008-0117
Sheet S2: Foundation Plan & Details
9. EOR, please specify the required post base connections.
10. EOR, it appears the footing 3'X3'X1' supporting the two 6X6 post at the corner of
the deck where detail 3/S 1 is cut will not support the design loads. Please note the
post supporting the 5-1/8X12. Submit analysis to justify with the two point loads
on the footing. IBC 1801.2
11. Deta113 and 3A: EOR, please submit analysis for the 2x10 ledger width bolts
spaced at 48: to support the design loads.
12. EOR please add section cut at the exterior deck. It appears based off the grade that
retaining walls are required but the drawing just show 1'2" wide footing at the
base. Please add a section cut at this level to show the amount of soil retained.
Sheet S3: First Floor Framing Plan & Details
13. EOR, please provide a detail for the hold down being installed into a glu-lam
beam. The glu-lam beam is a 5-1/8X16-1/2 in the center of the structures.
14. EOR, please specify the required shear wall to use between the hold-downs shown
on this sheet at the kitchen area. HD -3 is specified with out the required shear wall
noted.
15. There is no information for the attachment of the deck ledger. Please add this
information to the drawing with supporting analysis to justify. R502.2.2
16. EOR, submit analysis for the HGUS6.88/14 skewed hanger. Based off a width of
6.75 the maximum load in Simpson catalog must be reduced by .4 the load stated.
Please provide analysis to justify hanger specified. Simpson Hager options HGUS
page 182 C-2008 catalog.
17. EOR, please provide a detail for the 6-3/4X19-1/2 framing into the 6x6 post at an
angle. All post to beam connections should be specified and with the post
orientated the way drawn the post a detail should be specified and the required
connections specified.
18. EOR please provide a detail for the base of the 6x6 post bearing on the Double
floor joist. The width of the flange is 1.75 and double would have a width of 3.5"
and the width of a 6X6 is 5.5". Please provide a detail at these locations to show
complete load path.
Page 4of5
Plan Review Number 01
EECE4: EDM 08-12
Hillard Residence
2008-0117
19. EOR please clarify the required connection of the 5-1/8X18 top the concrete pier at
the deck.
20. EOR please clarify the required connection of the 6X8 to the concrete pier at the
deck.
21. EOR please specify the required connection of the 2x10 ledger to the concrete pier
in order to complete the review.
22. EOR, please provide detail for the guard required at the deck. The deck is over 30"
and guards are required.
Sheet S4: Second Floor & Partial Roof Framing Plan & Details
23. EOR, please provide a detail for the post base connection for the 12" diameter
wood post. This is supporting the 6-3/4X16-112 but the level below does not
specify this column or the required connections. Detail 6/S7 is only for the top
connections. Please modify accordingly. IBC 2304.9.7
24. EOR please provide a detail for the connection of the 4x4 post supporting the 5-1/8
wide glu-lam. How is this member being connected at the top? The beam width is
1-5/8 great then the bearing support.
25. EOR, submit analysis for the support for the 4X beams. The detail showing the
support is detail 1/S6. This should include all load combinations.
26. Please note the plate washer shall be a minimum of 3 x 3 x .229" plate washers at
all anchor bolts. The details through out the drawings state per shear wall
schedule. But the shear wall schedule does not specify this. R602.11-1. and IBC
2305.3.11
27. Detail 2: EOR, please provide analysis for the 2x12 ledger connections to support
the design loads. This is referenced on sheet S3.
Sheet S5: Roof Framing Plan
28. EOR, the over hanger at the roof reference 4157. Per wind analysis there will be
uplift forces that must be accounted for and the detail 4 does not specify any
method for this force to be resolved. Please modify accordingly.
Sheet S6: Details
Page 5 of 5
Plan Review Number 01
EECE#: EDM 08-12
Hillard Residence
2008-0117
29. Detail 1: EOR please submit analysis for the connections of the 2x8 to the 4x 10
considering uplift loads. Based off the dead load there will be uplift loads and A34
are not approved for the forces applied in this direction.
30. Detail 1: EOR it appears uplift will be at the wall on the 4xI0 and A35 as detail is
not approved for uplift forces. Please modify accordingly.
31. Detail 1, 3 and 4: EOR, please add dimension for the required locations of the
diagonal post. This is required m order to complete the review for the load transfer
requirements.
Sheet S7: Details
32. Detail 7: Design analysis submitted for this wall show the stability of sliding does
not have a safety factor of 1.5 as required per code. Please modify detail and
analysis accordingly. 113C 1806
33. Detail 7: EOR, the design analysis submitted specify the vertical reinforcement to
be placed at the edge but the detail show a 3" Clear. "d" shall be the distance from
the extreme compression fiber to the centroid of the tension reinforcement. With
the number 5 placed as specified the d= is 4.69". (8"-3-5116-4.69 but the analysis
used 4.75') Please resubmit analysis or modify the drawings accordingly. ACI
7.5.2.1 ACI 10.3
Additional corrections may be required following receipt of corrections and additional
information as requested.
Your plans are being reviewed concurrently with the Building Department, Fire
Department, Zoning Department and Public Works Engineering. Changes, clarifications
or additional corrections may be required subsequent to the Building Department plan
review when comments are received from the other concerned departments.
Should you have any inquiries regarding this letter, please contact Hoyt Jeter at (360) 874-
0562 between 8:00 a.m. and 5:00 p.m.
By:
Hoyt Jeter, P.E.
President
JALANDAU
ASSOCEATES
TECHNICALMEMORANDUM ammi-VEAL,mb;Ecwc; ummimscmcu
TO: :Jeannine Gral";:.Building Official
City of Edmonds Development Services Department,. Building Division
FRCiM: Dennis R. ;Stealer, P.E. {
DATE: March 1:8:, ` 008
RE: GE'OTicc IniICAL EER RE VIE WFOR ]EARTH SUBSIDE,NCE AND LANDSLIDE, HAZARD
AREA SutitKI I'AiLPA.CKAGE --PLAN REVIEW Na. PRE20070028
HILLI.ARD SFR W 15515 75"� PLAcE WEST
EDMONDS, WASHINGTON'
This technical memorandum provides. out geotechnical peer review of portions of the permit
package, submitted to the City of 'Edmonds (City) for the proposed referenced development within the
Earth Subsidence and Landslide Hazard Area (ESLHA) of North Edmonds, The purpose of this
geotechnical peer review was to review portions of the submittal package and assess its compliance with
City development and building permit regpirernei ts. as contained in Edmonds. Community Development
Code (ECD.C) Chapters .1.9.10 and 23.80. This geotechnical peer review was:accompl.ished in accordance
with Task Order No; ().8_04 of Landau Associates' On-call Geotechnical Engineering Services. A9reernent
with the City.
Wehave received. the following: information forwarded by the:City for review
Geotechnical Engineering Deport Proposed Single-Fanz ly: Residence; 756`x' Street Southwest
and 75"' Place West, Parcel No. 00:500900000101, Edmonds, WA, prepared for Mr. Ron
HiIl.iard.by Comdrstone. Geotechnical, dated January 22, 2007.
e Final Certechnicnl Declaration and Statement of Risk, Proposed Single -Family. Resirleitce,
156"' Street Southwest and 75" Place :West; Parcel No. 00-500900000101, Eelmonels; 141A,
prepared for Mr. Ron Hilliard by Cornerstone Geotechnical, dated December 12 "2007.
i
Supplemental Letter, Proposed Single -Family Residence, 15515 75"' :Place West,;' Edmonds,
WA; prepared for Mr. Ron Tlilliard by Cornerstone Geotechnical, dated February 8 2.008 -
Civil Engineering Drawings (3 sheets, including TESL' & Grading Pian, Drainage / Utilities
Plan, and Notes. and Details), prepared`by J. C. McDonnell Engineering, PC,,dated March 27,
2007.
Site Plan.. St mei ;dot` Rost .Hilliard,. prepared: by Pacific Geomatic Service, Inc., dated,
:November 9, 007,
;m Sile Platz, 1l lliard Resiclence,:.1551:5 ,75'!' Place W , _Edmonds, WA 98026 prepared ;by
Cornerstone Arelirteetural Group; datedMay 7, 2007.
13Q 2nd .Avenue South o Edmonds. WA. ! B020 . (425) 778-0$07 fax (425.) 778-6409 a wwwdandauinc:com
• Letter Re: Hilliard Residence, containing Lead Design Professional Designation and
Statement and Architect/Engineer Declaration, prepared by Cornerstone Architectural Group,
dated November 9, 2007.
• Letter Re: Hilliard Residence, containing Applicant / Owner Liability and Landslide
Acknowledgement, prepared by Cornerstone Architectural Group, dated December 18, 2007.
• Letter Re: Hilliard Residence 156`h Street SW, Edmonds, Washington containing Structural
Engineer Declaration, prepared by Peterson Strehle Martinson, Inc., dated December 18,
2007.
• Critical Areas Checklist (CA File No. 06-0058) submitted by Mr. Ron Hilliard, dated May 4,
2006.
• Storm Drainage Study for Ron Hilliard SFR, prepared by J. C. McConnell & Associates,
dated February 1, 2007.
• Structural Calculations for Hilliard Residence, Edmonds, Washington (PSM # 07048),
prepared by Peterson Strehle Martinson, Inc., dated December, 2007.
• Architectural and Structural Plan Set (including Sheets A3.1, A2.1, A2.2, A2.3, A3.2, A3.3,
A4.1, A4.2, A4.3, A5.1, A6.1, A6.2, AI0.1, Sl, S2, S3, S4, S5, S6, and S7) prepared by
Cornerstone Architectural Group, dated May 7, 2007.
• North Edmonds Earth Subsidence and Landslide Hazard Areas Map (with property location
noted) and signed certification as to property location), by Steve Barnes, Architect, dated
December 17, 2007.
The following sections provide our review comments.
GEOTECHNICAL REPORT
The geotechnical report prepared by Cornerstone Geotechnical on January 22, 2007 provided a
reasonably comprehensive evaluation and discussion of site conditions and risks, and provided
geotechnical recommendations for design. However, we noted in our Geotechnical Completeness Review
dated January 3, 2008 that the geotechnical report for the project was prepared prior to enactment of
Ordinance #3632 that provided for additional requirements related to development in Earth Subsidence
and Landslide Hazard Areas. Cornerstone Geotechnical provided a Supplemental Letter dated February
8, 2008 that provides additional geotechnical information and recommendations. In our opinion, the
combination of the January, 2007 geotechnical report and the February, 2008 supplemental letter
appropriately addresses the requirements of ECDC 19.10 and 23.80 for geotechnical reports.
3118108❑Edmdala5orojects107411441FiIeRm5R\GeotPeerReview tm.doe LANDAU ASSOCIATES
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STRUCTURAL PLANS AND CALCULATIONS
Our review of the structural pians and calculations was limited to the aspects related to the
geotechnical recommendations.
Building Code
We note that the geotechnical report, structural calculations, and structural drawings (notes on
Drawing S 1) all reference the 2003 building code. We understand that the 2006 building code applies to
this project. We recommend that the structural and geotechnical documents be updated as appropriate to
reflect the requirements of the 2006 code and be referenced as such.
Foundations
Cornerstone Geotechnical provided recommendations for foundation support, including a
recommended allowable soil bearing pressure of 1,500 pounds per square foot (psf). They also
recommended that the footing subgrade be over excavated and backfilled with at least two feet of
imported, compacted structural fill; that 1 to 2 ft of compacted structural fill be placed beneath slab -on -
grade floors; and that the footings be designed to span at least 10 ft. In our opinion, these
recommendations are appropriate considering the structure will be supported on shallow foundations
above slide debris that provides variable foundation support. It does not appear that the structural
engineer has incorporated these recommendations into the structural plans. The "Foundations" note on
sheet S 1 identifies an allowable soil bearing pressure of 2,000 psf, makes no mention of over excavation
and backfill beneath footings or slabs -on -grade, and provides for compaction criteria that is not consistent
with the geotechnical report.
We recommend that the structural plans be revised to:
• Indicate the design allowable bearing pressure of 1,500 psf.
• Incorporate the geotechnical engineer's recommendations for over excavation and backfill
with imported, compacted structural fill beneath foundations and slab -on -grade floors, and
include the geotechnical engineer's recommended criteria for placement and compaction of
structural fill.
We also recommend that the structural engineer confirm that the foundations are designed to span
at least 10 ft.
Soldier Pile Excavation Support
Cornerstone Geotechnical recommends in their February 8, 2008 Supplemental Letter that a
soldier pile wall should be used to support the cut face in the vicinity of the northeast corner of the
3!48/08 44Edmdatalprojects10741144TileRm4R4GeotPeerReview tm.doc LANoAU ASSOCIATES
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building. Given the depth of excavation in slide debris at this location near the base of a steep slope, this
is a prudent recommendation, in our opinion. This recommendation has not been incorporated into the
plans. We recommend that Cornerstone Geotechnical work with the design team to establish the
appropriate limits and extent of this recommended soldier pile wall. The soldier pile wall location and
details should be clearly shown on the Drawings. We also recommend that the revised Drawings and the
soldier pile wall calculations be submitted to the City for review.
Debris Walls
Cornerstone Geotechnical has recommended that the project include debris walls located along
the north and east sides of the house as either a portion of the house foundation wall, a separate retaining
wall, or both. We concur with this general recommendation. Landau Associates observed the landslide
in the adjacent 156"' Street SW right-of-way that occurred in early January, 1997. The debris slide flowed
down the slope and impacted and damaged the garage of the property immediately to the south of the
Hilliard property. We are also aware of previous debris slides that have occurred within the vicinity of
this project where debris walls have been instrumental in limiting the damage to the residences and have
increased the safety of the residents.
Cornerstone Geotechnical has made recommendations for debris walls, including potential wall
heights as a function of distance from the toe of the slope to achieve reasonable protection from debris
slides. The plans show a short concrete debris wall behind the residence, and the structural calculations
indicate that walls on the north and east sides of the house have been designed for the higher lateral
pressures associated with debris impact as recommended by the geotechnical engineer. Cornerstone
Geotechnical states in their December 12, 2007 letter that they have reviewed the structural plans and the
basement and debris walls have been designed with adequate heights, per the geotechnical report. In a
personal communication between Chuck Couvrette of Cornerstone Geotechnical and Dennis Stettler of
Landau Associates on March 11, 2008, Mr. Couvrette also confirmed that he has reviewed the concrete
retaining wall designs and they are consistent with the recommendations for debris walls by Cornerstone
Geotechnical.
The Cornerstone Geotechnical report recommends a passive earth pressure of 175 pcf for design
of standard walls and 125 pcf for debris walls. The reason for this difference in passive resistance is not
clear and from review of the structural calculations it is apparent that the structural engineer has used 175
pcf in his calculations. In a personal communication between Chuck Couvrette and Dennis Stettler on
March 11, 2008, Mr. Couvrette indicated that the correct passive pressure for both wall types should be
175 pcf. We recommend that this correction to the geotechnical report be confirmed in writing by
Cornerstone Geotechnical.
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Geotechnical monitoring and inspection of earthwork by the Geotechnical Engineer of Record is
required, including placement and compaction of structural fill, foundation bearing, temporary shoring,
retaining walls, and retaining wall backfill and drainage. The structural plans should note this
requirement.
CIVIL PLANS
The grading plans identify that an estimated 510 cubic yards (yd3)of foundation cut and 303 yd3
of fill will be required for the project. Grading in excess of 500 yd requires State Environmental Review
and a SEPA Checklist (See "Earth Subsidence and Landslide Hazard Area of North Edmonds Procedures
& Permit Submittal CheckIist," Item 7.a). These documents were not included with the package of
review materials that we received. If this has not been submitted, the City should request the applicant
complete the SEPA Checklist and submit for review by the City.
The TESC and Grading Plan establishes clearing limits that are approximately at the base of the
slope and identifies that native vegetation on the slope should be protected. We concur that protection of
the native vegetation on the slope is important.
Landscaping plans for the area surrounding the house were not included in the plans provided for
our review. We recommend that basic landscaping plans for the property be provided that confirm that
the steep slope areas will remain protected by native vegetation and that additional cuts, fills, or retaining
walls are not planned as a part of landscaping improvements to the property.
Several trees have been identified on the slope that are either dead or leaning and the plans call
for their removal The TESC and Grading Plan (Construction Sequence item #7) requires that the
contractor "Demo and preserve trees as required." The architectural site plan (Sheet Al. I) calls out the
location of six dead or leaning trees on the slope for removal. The January 22, 2007 geotechnical report
recommends removing these six trees, as they present a potential hazard to life and structure. The
geotechnical report recommends that the trees be cut and removed from the slope, but the root system
should be left in place. We concur with this recommendation regarding tree removal.
We recommend that the TESC and Grading Plan be revised to more specifically call out the trees
to be cut and removed from the slope, with the requirement that the root system be left in place in
accordance with the geotechnical report recommendations. In addition, it has been our experience that
removing large trees from the slope can result in substantial disturbance to the existing native vegetation
on the slope, depending on the method used and care taken by the contractor. The TESC and Grading
Plan should also require that the contractor restore native vegetation on the slope as necessary to repair
damage to the existing vegetation due to tree removal and provide TESC measures as appropriate for
areas of ground disturbance.
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The sequence of construction noted on the TESC and Grading Plan needs to be modified to
require that the TESC be in place and inspected prior to any construction or site clearing (as currently
written, the TESC would be placed after clearing and grubbing, which is not acceptable).
The note under Construction Sequence of Sheet 1 regarding the pre -construction meeting needs to
be modified to include the Geotechnical Engineer of Record [see City of Edmonds Earth Subsidence and
Landslide Hazard Area Temporary Erosion and Sediment Control (TESC) Requirements].
Inspection, maintenance, and regular reporting of TESC measures by the Geotechnical Engineer
of Record are required [see the City of Edmonds Earth Subsidence and Landslide Hazard Area
Temporary Erosion and Sediment Control (TESC) Requirements]. This requirement should be noted on
Sheet 1 and the owner or lead design professional should arrange for these services with the Geotechnical
Engineer of Record.
The geotechnical report recommends that earthwork be conducted during the drier months. This
is consistent with City requirements that earthwork during the winter season between October I and April
30 is restricted. We recommend that the TESC and Grading plans specifically indicate that earthwork is
restricted between October 1 and April 30 and any earthwork in this time period requires approval from
both the Geotechnical Engineer of Record and the City Building Official.
REQUIRED STATEMENTS AND DECLARATIONS
We reviewed the submittal package to confirm that the various statements and declarations as
required by the City for development within the Earth Subsidence and Landslide Hazard Area have been
appropriately addressed.
• Cornerstone Architectural Group has submitted the required Lead Design Professional
Designation and Statement.
• Cornerstone Architectural Group has submitted the required Applicant/Owner Liability and
Landslide Acknowledgement.
• Cornerstone Geotechnical has provided a Final Geotechnical Declaration and Statement of
Risk letter dated December 12, 2007 that largely addresses the City requirements. However,
the geotechnical engineer has not stated that they have reviewed the erosion and sediment
control plans and has not provided a statement regarding the adequacy of the TESC plans, as
required by the City. We recommend that this issue be addressed in a supplemental letter or
revision to the December 12, 2007 letter.
• Cornerstone Geotechnical further described site risks in a supplemental letter dated February
8, 2008 and adequately addressed the site classification and hazard zones as contained in
Landau Associates 2007 North Edmonds Earth Subsidence and Landslide Hazard Area
Summary Report. In our opinion, the combined December 12, 2007 letter and February 8,
2007 supplemental letter appropriately address the City requirements for Geotechnical
Hazard Identification/Declaration and Statement of Risk.
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0 Peterson Strehle Martinson, Inc. has submitted the required Structural Engineer Declaration.
OTHER ISSUES
We noted in our Geotechnical Completeness Review letter of January 3, 2008 that the location of
the property marked on the North Edmonds Earth Subsidence and Landslide Hazard Areas Map appears
to be incorrect. The property marked is not adjacent to the 156` Street SW right-of-way. We recommend
that the applicant resubmit this plan to the City with the correct location, if they have not already done so.
This technical memorandum has been prepared for use by the City of Edmonds in evaluating the
adequacy of permit submittal documents related to the proposed Hilliard single family residence at 15515
75'x' Place West. The focus of this review was the geotechnical aspects of the application. The purpose of
the review was to assess the adequacy of the application documents for compliance with City
requirements contained in ECDC 23.80 and ECDC 19.10 and conformance with conventionally accepted
geotechnical engineering practices. This geotechnical peer review by Landau Associates does not lessen
the requirements for the applicant's geotechnical consultant and other design professionals to prepare an
appropriate design for the site conditions.
We appreciate this opportunity to be of service to the City. Please contact us if you have any
questions or if we may be of further service.
DRS/rgm
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