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2016-0532 Miniaylo retaining walls2 - Adams Resource Consultants.pdf City of Edmonds PLAN REVIEW COMMENTS BUILDING DIVISION (425) 771-0220 DATE: December 21, 2016 TO: Slavik Miniaylo th 7316 164 Street SW Edmonds, WA 98026 FROM: Chuck Miller, Plans Examiner RE: Plan Check: BLD2016-0532 th Project Address: 7316 164 Street SW Project: Miniaylo retaining walls Scope: Repair/rebuild existing unpermitted retaining walls in ESHLA – Chapter 19.10 ECDC and Chapter 23.80 ECDC disapproved Please be advised that the building plans for the above referenced project have been for the purposes of obtaining a building permit. During a review of the plans by the Building Division for compliance with the applicable building codes, it was found that the following . information, clarifications, or changes are neededReviews by other divisions, such as Planning, Engineering, or Fire, may result in additional comments that require attention beyond the scope of this letter. Unresolved items that recur on this list appear in italics. A complete review cannot be performed until the revised plans/documents, including a written response in itemized letter format indicating where the ‘clouded’ or otherwise highlighted changes can be found on the revised plans, have been submitted to a Permit Coordinator. nd Resubmittals must be made at the Development Services Department on the 2 Floor of City Hall. Permit Center hours are M, T, Th, & F from 8am-4:30pm and from 8:30am-12pm on Wednesdays. General Review Note: 1.On the City of Edmonds ‘Residential Building Permit Application’, the noted scope of work is to “Redo (sic) of leaning retaining wall” and the ‘check-box’ for ‘Retaining Wall’ has been selected ‘Yes’ with an added note, “repair”. The application was accepted under the premise that the repair work was to be performed to maintain the purpose and integrity of previously permitted work and that during the review process the allowance for, limitations of, and required construction of the retaining walls would be determined. Unfortunately, during the review process no record of application, review, or approval for the construction of the walls could be found. th Regarding the ‘REVISED Geotechnical Assessment for New Retaining Wall at 7316-164 Street SW’ – reference ‘J 111-01-16’- prepared by Adams Resource Consultants (ARC): 2.The following were noted as being reviewed as part of the assessment done in support of the permit application: Letter dated January 7, 2005 from Cornerstone Geotechnical, Inc., to Clay · Enterprises. Plan Map titled: “Site Plan for House Construction,” by Partners Architectural, dated · June 10, 1999. Applicable City of Edmonds codes: a) Chapter 23.40 Environmentally Critical Areas · General Provisions, b) Chapter 23.80 Geologically Hazardous Areas and c) Retaining Wall Permit Submittal Requirements #B62. Unresolved a.- Clarify the applicability of the letter from Cornerstone Geotechnical, Inc. in support of the current permit application. The letter from Cornerstone Geotechnical regards the garden area/concrete planters to the immediate west of the residence driveway that were part of an ‘Order to Correct Violation’, ‘Notice of Civil Violation’, Hearing Examiner decision under case number ‘V-03-173’, and ultimately permitted under permit BLD2004-1037. The approval was for that area alone with a noted condition that “Any future development will be required to demonstrate compliance with the Critical Areas Variance criteria in effect at that time.”. The letter from Cornerstone dated after the Hearing Examiner decision is bound to that condition and does not appear to mention the presence of retaining walls of the height or configuration of those depicted in the provided photographs. The response to the earlier plans review comment states : “Our letter (April 21, 2016) noted that as part of our assessment we have reviewed several documents. The documents reviewed included but were not limited to the three items listed in our letter. It is our professional opinion that the letter from Cornerstone (2005) is significant in that it supports several key factors that assist with the general stability, performance and foundation conditions at the site. The area to the Specifically the letter from Cornerstone indicates that “ northeast to north side of the existing residence is now landscaped with a low block wall (emphasis added by ARC) , grass and shrubs. A low berm has also been place in this area to direct surface water away from the top of the slope.” We have not observed any other low block wall in this general area north of the residence near the low berm. Considering this, we believe the above stated reference concerns the block walls we are asked to evaluate. Thus, we can assume from this description that the settlement we have observed in the block walls north of the residence has occurred after the written observations by Cornerstone (2005) or within the last 10 or so years without noticeable disturbance of the steep slopes to the north and/or west. This is applicable to our efforts because it is a valuable piece of information regarding the integrity of the steep slope and native soil in that area.” Page 2 of 5 The earlier letter from ARC (dated April 21, 2016) stated: “As part of our assessment we have reviewed the following:”, listed the three documents referenced in the earlier plan review comment, and followed with: “In summary, based on our site observations and the previously listed information…”. There does not appear to be any mention of additional information used in the assessment by ARC. While the letter from Cornerstone may be perceived by ARC to have some value in determining the general stability, performance and foundation conditions at the site, the failure that occurred in a relatively short period of time of the wall that ARC believes to be that mentioned in the letter calls into question the construction of the wall, the ability of the soils to support it, and the stability of the slope behind the failing wall. Resolved b.- A site map showing the location of the subject retaining walls and the proposed repairs has been prepared and submitted for review and approval under this permit application. Unresolved c. - Clarify the omission of Chapter 19.10 ECDC in the referenced applicable codes regarding permitted activities allowed in a geologically hazardous area. Chapter 19.10 ECDC is referenced in Chapter 23.80 ECDC and provides the required procedures related to the issuance of permits within designated earth subsidence and landslide hazard areas of the city. The current permit application and the submitted documentation do not meet the requirements of Chapter 19.10 The response to the earlier plan review comment states ECDC. : “We have reviewed the code and requirements referenced above and believe we have addressed these adequately for the existing conditions, features and proposed activities that will occur near the geologically hazardous area. The following conclusions and recommendations meet or exceed the City’s requirements based on: a) our observations of the geologic strata exposed on the steep slopes, b) hand auger explorations in the lawn area north of the lower wall, c) observations of conditions exposed in exploration test pits extending beneath the existing upper wall, and d) our slope stability calculations. Exceptions to the requirements in the City Code Section 19.10.030 are described below; (1)We have combined the North Edmonds Subsidence and Landslide Hazard Map, Vicinity Map and topography into one submittal, Figure 1. (2)We have not included any survey topography with this design in consideration of the small area of change to existing grades. (3)Our Civil site plans are included in this submittal. (4)There is no tree cutting or clearing required for this project. (5)This letter combined with our letter dated (April 21, 2016) comprise the necessary Geotechnical reporting for this project. (6)Declarations, if required, will be supplied by the Owner. (7)No architectural or structural plans are needed for this project. (8)The owner is directed to complete this project using mostly hand tools and thus no bonds, covenants or contractor insurance are needed for completion of this project.” Page 3 of 5 The documents submitted at the time of permit application and the additional information provided in response to the earlier plan review comments do not appear to meet the requirements specified in ECDC 19.10.030 as follows: A copy of the North Edmonds Earth Subsidence and Landslide Hazard Map · shall be included in the submittal checklist materials per ECDC 19.10.030.C. The vicinity map shall be suitable for locating the site and include · information related to existing conditions on or near the site, based on the topographic map and survey and shall designate all known landslide masses, or debris flows or mud flows on or near the site which could threaten the proposed structures within 100 feet, as referenced, noted, described or discussed in the geotechnical report per ECDC 19.10.030.D. The applicant shall submit a topographic map and survey prepared and · stamped by a licensed land surveyor, prior to studies and evaluations by the geotechnical engineer, and shall show the information specified per ECDC 19.10.030.E.1 through ECDC 19.10.030.E.6. There is not an allowance for combining the above referenced documents into one submittal due to the amount and detail of the information required to be provided on the individual documents. The combined information represented in ‘Figure 1’ does not meet that specified for each of the documents listed above. An additional separate topographical drawing shall be submitted with the · information specified per ECDC 19.10.030.E.7. There does not appear to be an exemption in the submittal requirements based on the size of the area of change to existing grades. The noted ‘small’ area of change appears to extend approximately 130 feet across the top of and within 20 feet of the steep slope. Civil-engineered plans, prepared and stamped by a state of Washington · licensed civil engineer, incorporating geotechnical report recommendations affecting applicable civil design and details as specified per ECDC 19.10.030.F.1 through ECDC 19.10.030.F.8. Civil site plans could not be found among the submitted construction documents. A geotechnical report and evaluation of the subsurface soil conditions shall · be prepared by a geotechnical engineer and include the applicable information required per ECDC 19.10.030.H.1 through ECDC 19.10.030.H. The relevant information provided separately in the reports prepared by ARC dated April 21, 2016 and November 28, 2016 should be combined to form a comprehensive document that establishes the site conditions, concerns, and required measures to construct and maintain the proposed structure. The provided information does not appear to reference the Landau Associates Summary Report (2007), to note whether or not specific hazards exist on the site and the means to address them, or to provide an analysis of bluff retreat as required in the above referenced ordinance. The applicant shall submit declarations, disclosures, covenants and waivers · as required by ECDC 19.10.040 per ECDC 19.10.030.K. The declarations, disclosures, covenants and waivers as required per ECDC 19.10.040.A through ECDC 19.10.040.F are to be provided at the time of application as part of a complete permit submittal. Page 4 of 5 The applicant shall submit, consistent with the findings of the geotechnical · report, detailed structural plans with corresponding calculations prepared and stamped by the structural engineer of record. The plans should note/represent the required site preparation, specified materials, installation criteria, methods of construction (such as ‘by-hand’), conditions of use, monitoring, limitations, and any other concerns regarding the proposed project to guide proper review, construction, and inspection of the work to be completed and the ongoing maintenance of the walls. Among other items, the provided ‘Sections and Details’ on sheet ‘N2.0’ to not appear to indicate the placement of drain rock behind the walls, the drainage discharge, or the placement of monitoring points, including the geotechnical boreholes, and watering limitations noted in the report prepared by ARC dated April 21, 2016. Those details are noted in the report prepared by ARC dated November 28, 2016 as being considered “…to be crucial to the overall success for completing this project.”. The applicant shall submit documentation of required bonds, frozen funds or · adequate instrument of credit. The applicant shall submit a copy of the contractor’s general public liability insurance pursuant to ECDC 19.10.050 per ECDC 19.10.030.J. There does not appear to be a condition, such as completing the project using mostly hand tools, limiting the applicability of the requirements of ECDC 19.10.050 to this project. Additional plan review comments regarding the construction documents submitted to date: 3.To date no information has been provided that appears to substantiate the installation as part of previously permitted work any of the walls, patio, and stairs observed and referenced in the submitted construction documents. Therefore, any allowance for the continued existence or replacement of, or repairs, improvements, or additions to, those structures must be obtained through the permitting process as that of a project proposed as ‘new’ or ‘original’ construction. If there is other information relevant to the installation of the walls, patio, and stairs noted in the documents provided as part of this permit application that appear to substantiate the installation of those structures as part of previously permitted work, it could not be found. 4.References to an ‘observation of compliance to recommendations made during site visits in the past by a geotechnical engineer’ and a letter prepared after the issuance of a permit noting the existence of a low wall not included in the scope of work under a permit and that is believed to be among those that ARC has been asked to evaluate due to a relatively premature failure will not be considered without supporting documentation regarding the ‘original’ construction of those elements observed or noted. 5.The scope of work proposed under this permit application must be clearly stated on the City of Edmonds ‘Residential Building Permit Application’, be clearly represented on construction drawings and be supported as required by the applicable provisions of ECDC 23.80 and ECDC 19.10 and as noted in the above plan review comments. At the completion of the project, those elements proposed under the scope of work must be as permitted or the site must be returned to its previously undisturbed condition. Page 5 of 5