Abbott Residence PeerReview_tm.pdf
TECHNICAL MEMORANDUM
TO: Leif Bjorback, Building Official
City of Edmonds Development Services Department, Building Division
FROM: Carlo Evangelisti, P.E.
DATE: February 3, 2016
R E: G EOTECHNICAL P EER R EVIEW
S UBMITTAL P ACKAGE FOR S TRUCTURE L OCATED IN A C RITICAL A REA
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A BBOTT R ESIDENCE 16404 75 P LACE W EST
E DMONDS, W ASHINGTON
This technical memorandum provides our geotechnical peer review for the permit submittal
package that was submitted to the City of Edmonds (City) for the proposed referenced development within
a critical area located in Edmonds, Washington. The purpose of our geotechnical peer review is to review
portions of the submittal package and assess its compliance with City development and building permit
requirements as contained in Edmonds Community Development Code (ECDC) Chapter 19.10 for sites
designated within or near the North Edmonds Earth Subsidence and Landslide Hazard Area (ESLHA). This
review also assesses the submittals compliance with the requirements of Chapters 23.40, 23.50, 23.80, and
23.90 of the ECDC as required or noted in Chapter 19.10. This geotechnical peer review was accomplished
in accordance with Task Order No. 16-01 of La-Call Geotechnical and Environmental
Engineering Services Agreement with the City.
We reviewed the following information forwarded by the City:
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Submittal Plan Set for 16404 75 Pl. W., Edmonds, Custom Residence (26 Sheets, including
Sheets A1 through A8 and Sheets S1 through S7) prepared by Ronald D. Johnson, Architect,
and D.R. Strong Consulting Engineers, dated December 12, 2015.
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Land Clearing and Tree Cutting Plan (1 sheet) for 16404 75 Pl. W., Edmonds, prepared by
Ronald D. Johnson, Architect.
City of Edmonds Critical Areas Checklist, prepared by Derek Abbott, ACH NW, LLC, dated
March 6, 2015.
Lead Design Professional Designation, prepared by Ronald D. Johnson, Architect, dated
December 18, 2015. This designation is signed and sealed by Ronald D. Johnson.
Structural Engineer Declaration, prepared by Wendell Reed, P.E., CBO, dated March 31, 2010.
This designation is signed and sealed by Wendell Reed.
Geotechnical Plan Review Letter, prepared by Nelson Geotechnical Associates, Inc., dated
December 7, 2015. This letter is signed and sealed by Lee S. Bellah, L.G. and Khaled M.
Shawish, P.E.
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Letter RE: Abbott Residence 16404 75 Pl W, prepared by D.R. Strong Consulting Engineers,
dated September 4, 2015. This letter is signed and sealed by Walter J. Shostak, P.E.
130 2nd Avenue South Edmonds, WA 98020 (425) 778-0907 fax (425) 778-6409 www.landauinc.com
North Edmonds Earth Subsidence and Landslide Hazard Areas Map, prepared by Landau
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Associates, Inc., dated May 2006. Edited to show parcel location for 16404 75 Place West.
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Preliminary Geotechnical Engineering Evaluation, Abbott Residence, 16404 75 Place West,
Edmonds, Washington prepared by Nelson Geotechnical Associates, Inc., dated March 27, 2015.
The report is signed and sealed by signed and sealed by Lee S. Bellah, L.G. and Khaled M.
Shawish, P.E.
Memorandum re: Updated Geotechnical Engineering Recommendations, Abbott Residence
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Structural Slab Pin Piles, 16404 75 Place West, Edmonds, Washington prepared by Nelson
Geotechnical Associates, Inc., dated May 6, 2015. The memorandum is signed and sealed by
signed and sealed by Lee S. Bellah, L.G. and Khaled M. Shawish, P.E.
Affidavit of Earth Subsidence Landslide Hazard Area Permit Posting, dated December 10, 2015
prepared by RDJ Group / Derek Abbott.
The preceding documents comprise the majority of required application submittals identified in
Section 19.10.030 of the ECDC. However, we found the following deficiencies as required by the ECDC:
Storm drainage calculations are not included.
Structural calculations are not included.
Bonds, covenants, and contractor public liability insurance are not included.
The sections below provide our specific geotechnical peer review comments related to the
submitted documents.
R EVIEW OF R EPORTS
The preliminary geotechnical report provides a good discussion of site conditions and risks, and
generally provides geotechnical recommendations appropriate for design. The report appears to adequately
document existing site conditions based upon field reconnaissance and subsurface explorations, and
acknowledges the presence of, and adequately evaluates, seismic, erosion and landslide hazards on the
property and references the 2007 Landau Associates Summary Report for the North Edmonds ESHLA.
The preliminary geotechnical report addresses these issues in the form of geotechnical recommendations
for the construction of augercast pile foundations, retaining walls, slabs on grade, excavations and slopes,
temporary shoring, drainage, and earthwork.
The updated geotechnical recommendations memorandum provides a good evaluation regarding
the use of 4-inch diameter driven pin piles to support structural slabs-on-grade.
While the preliminary geotechnical report and associated memorandum with updated geotechnical
recommendations provide a complete geotechnical evaluation needed for design and construction, we
recommend that a final geotechnical report be prepared and submitted incorporating conclusions and
recommendations from both documents.
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C IVIL, A RCHITECTURAL, AND S TRUCTURAL P LANS
The civil engineering plans appear to include the necessary details for temporary erosion and
sediment control (TESC) as shown on the . Provisions for foundation
drainage are included in the architectural and structural plans. An addition to the civil plans should include
fill/soil stockpile limitation provisions and slope protection plans, in accordance with ECDC 19.10.030.
In addition, the civil plans should be revised to reflect such provisions, including specific location(s) for
stockpiling, height restrictions on stockpiles, and guidelines for protection and maintenance of stockpiled
fill/soil.
We also recommend that the civil plans include notes that explain the ECDC limitations on site
access and special inspection requirements for TESC between October 1 and April 30. The contractor
may not be aware of the site access restrictions and special inspection requirements unless this is explicitly
stated on the civil plans.
In addition, we found the following deficiencies related to the plans that were submitted:
The certification statement on the cover sheet needs to be signed and dated.
The topographic map and survey does not include the tax account parcel numbers.
Bottom elevations of grade beams or foundation elements are not shown on the foundation plan
sheet.
R EQUIRED S TATEMENTS AND D ECLARATIONS
Statements and declarations from the design professionals as required by the City, as applicable,
were included in the submittal package. The Structural Engineer Declaration, prepared by Wendell Reed,
P.E., CBO, is dated March 31, 2010. This declaration predates the submittals. We recommend that this
declaration be reviewed and resubmitted with a current date.
This technical memorandum has been prepared for use by the City of Edmonds in evaluating the
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adequacy of permit submittal documents related to the proposed residential structure located at 16404 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 19.10 and conformance with conventionally accepted geotechnical engineering
practices. This geotechnical peer review by Landau Associates does not lessen the requirements for the
and other
design professionals to prepare an appropriate design for the site conditions.
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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.
CE/SZW/rgm
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