AES #3.pdfAssociated Earth Sciences, Inc.
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June 5, 2006
Project No. KE03537B
City of Edmonds
Community Services Department
1215' Avenue North
Edmonds, Washington 98020
Attention: Ms. Jeannine Graf
Building Official
Subject: 2' Geotechnical Plan Review
City of Edmonds Plan Review No. 05-210
Michel Residence
1591174"' Place West
Edmonds, Washington
References: Geotechnical Plan Review
Associated Earth Sciences, Inc.
June 29, 2005
Geotechnical Recommendations - New Michel Residence
Dennis M. Bruce, P.E., May 17, 2006
Grading, Drainage, Paving, TESL Plan, Sheet 1 of 1
Donna L. Breske, P.E., dated May 20, 2004 (stamped March 13, 2006)
Architectural Plans Sheets Al.1 through A8
McGrew Michel, dated May 25, 2005, Revised May 15, 2006
Structural Plans Sheets S-1 through S-5 RECEIVED
Custom Design and Engineering, Inc., dated May 25, 2005
JUNE
Dear MS. Graf: DEVELOPMENT SERVICES CTR.
CITY OF EDMONDS
As requested, Associated Earth Sciences, Inc. (AESI) has completed a second geotechnical
review of the above -referenced geotechnical report and development plans for the subject
Michel residence. AESI earlier completed the above -referenced first geotechnical review of
the project on June 29, 2005. Our geotechnical reviews have been completed with respect to
Kid&md Office • 911 Fifth Avenue, Suite 100 • Ki&6nd WA 98033 • P (425) 827-7701 •.F (425) 827-5424
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www.aesgeo.com
the Meadowdale Earth Subsidence Landslide Hazard Area Checklist criteria as contained in the
City of Edmonds Ordinance #2661 and the Edmonds Community Development Code (ECDC)
Chapter 19.05.
Review Comments
Our review found that the following comment items identified in the first plan review have still
not been adequately addressed:
+ Review of the project structural engineering plans by Custom Design and Engineering,
Inc. Sheets S-1 through S-5, stamped May 25, 2005, show that the residence will be
supported on 4 -inch -diameter driven pipe piles. Notes should be added to Sheet S-5
calling out that pile bearing should be within the undisturbed soils at a minimum depth
of 25 feet below the existing ground surface and be inspected by the project
geotechnical engineer. Additionally, allowable axial compressive capacities of the pipe
piles, vertical load testing requirements, and coupling details or notes should be
indicated on the plans. Sheet S-1 Foundation Notes .Items I and 9 should delete
reference to foundation bearing capacity and indicate a pile -supported foundation will
be used. Sheet A5 of the architectural plans should reference that the foundation will
be pile -supported.
• Given the variable consistency and loose to medium dense, unconsolidated condition of
the surficial site soils, the planned excavation slopes are likely to be unstable and may
require laying back the excavation face at 1.5H:1V (Horizontal: Vertical), or shallower,
as necessary. Notes should be added specifying that the project geotechnical engineer
should be on-site to evaluate the suitability of any temporary slope cuts over 4 feet high.
• The above -referenced plans show a proposed two-tiered rockery system with labeled
tier heights up to 7 feet high and calculated tier heights up to 7.5 feet high based on the
grading plan. A City of Edmonds "Tiered Rockeries Detail" is included on the grading
plan with a note indicating that the rockery tiers over 8 feet high must be designed and
stamped by a licensed professional engineer, or if the City determines that special
conditions exist, such as the site being located in a critical area or the Meadowdale
Earth Subsidence Landslide Hazard Area. The site is located within the Meadowdale
Earth Subsidence Landslide Hazard Area, and the rockeries appear to face landslide
debris. AESI recommends site-specific engineering design of any rockery over 4 feet
high located within the site's disturbed landslide debris soils. The rockeries should be
designed and stamped by a licensed professional engineer and include geogrid
reinforcement as part of the design. The design should consider surcharge effects of the
upper wall on the lower wall, and due to sloping backfill conditions.
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• Site drainage improvement should consist of controlling surface water flow and ground
water seepage from the base of the adjacent slope. Add a surface drainage Swale to
divert surface water away from the cut slope above the driveway courtyard and east
wall of the garage. City code allows for non -building at -grade surface improvements
within the 15 foot building setback. Thus, a shallow graveled surface swale could be
placed above these areas within the flatter portion of the 1S foot building setback. The
swale should be approximately 3 feet wide by 1.5 feet deep.
Conclusion
In summary, it is AESI's opinion that if the conditions discussed in this review are included
with the construction plans for the proposed Michel residence, the requirements of Chapter
19.05 of the ECDC should be substantially satisfied.
This letter has been prepared for the exclusive use of the City of Edmonds Community Services
Department, Engineering Division and their agents for specific application to this project.
Within the limitations of scope, schedule, and budget, our services have been performed in
accordance with generally accepted geotechnical engineering and engineering geology practices
in effect in this area at the time our review was completed. No other warranty, express or
implied, is made.
We appreciate the opportunity to be of service to the City of Edmonds on this project. Should
you have any questions regarding this letter or other geotechnical aspects of the project, please
call us at your earliest convenience.
Sincerely,
ASSOCIATED EARTH SCIENCES, INC.
Kirkland, Washington
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