Landau Supplemental Peer Review 9-20-10.pdf
Geotechnical Peer Review of Submittal Package for Earth Subsidence and Landslide Hazard
Area, Plan Review Comments, letter prepared by Reed & Associates, PS, dated July 12, 2010.
Gold Residence (South), Response to Planning Division plan review comment letter dated
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June 8, 2010, for property located at 16200 75 Place West, Edmonds, Plan check # BLD
20100339, letter prepared by Reed & Associates, PS, dated August 26, 2010.
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Gold SFR, 16200 75 Place, Edmonds, Washington, Plan Review Comments, letter prepared
by Reed & Associates, PS, dated July 7, 2010.
City of Edmonds Record of Lot Line Adjustment, dated July 29, 2010.
Gold Residence South Lot Revegetation Plan (Sheets L-1 through L-4), plans prepared by The
Jay Group, dated May 25, 2010.
Our review of the resubmitted permit package indicates that most of our previous review
comments have been addressed.
The letter from Nelson Geotechnical Associates (NGA) dated August 25, 2010 has provided
further discussion of the potential risk posed by a large-scale, deep-seated landslide on the property.
Landscape plans have been submitted that address the previous recommendations provided by NGA dated
February 12, 2010 and our June 18, 2010 review comments. Revised lateral earth pressures to address
sloping backfill behind retaining walls have been provided.
The structural engineer has updated the retaining wall design to reflect the planned 3H:1V
backslope and used active lateral earth pressures consistent with the geotechnical engineer’s revised
lateral earth pressures for sloping backfill.
It appears that the footing detail callout for the garage
The footing schedule has been updated.
foundations and basement retaining wall should be 2/S-2 instead of 2/S-5, and 3/S-2 instead of 3/S-5.
Please review the callouts for footing details and revise as appropriate.
Needed revisions or clarifications regarding the Environmental Checklist were noted in Landau
Associates’ June 18, 2010 review comments. The resubmitted permit review package that we received
did not contain the revised Environmental Checklist. However, our previous review comments were
addressed in the resubmitted permit review package for the Gold North residence to reflect the site slopes
and landslide hazard conditions that pertain to both of the adjacent properties.
The civil plans have not incorporated the requirement for involvement of the geotechnical
engineer in the pre-construction meeting and monitoring requirements of the temporary erosion and
sediment control (TESC) measures as recommended in our June 18, 2010 review comments. Our
previous review comment is repeated below:
“Inspection, maintenance, and regular reporting of TESC measures by the Geotechnical Engineer
of Record are required \[see the City ESLHA Temporary Erosion and Sediment Control (TESC)
Requirements\]. The pre-construction meeting needs to include the Geotechnical Engineer of
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Record (see City ESLHA TESC Requirements).” We recommend that the notes be revised
accordingly.
The connection of the retaining wall drains to the site storm drainage system has been clarified.
* * * * * *
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 Gold (South) single-family residence at
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16200 75 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/CBT/ccy
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