DEA-Shoring Wall Review Memo_2019-08-26.pdfDAVID EVANS
ANDASSOCIATES INC.
DATE: August 26, 2019
TO: Jen Machuga
City of Edmonds, Public Works Department, Engineering Division
121 5th Avenue North
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Edmonds, WA 98020
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FROM: Rebecca Boggan, PE
SUBJECT: Larsen 3-Lot Short Plat — Shoring Wall Review
PROJECT: City of Edmonds, 2019 On -Call Structural Services
COED0000-0014
CC: Kirk Harris, PE, PMP
As requested by the City of Edmonds, David Evans and Associates, Inc. (DEA) reviewed the shoring design for
the Larsen 3-Lot Short Plat project. The Shoring Wall Revision 1 Review was performed in May 2019 and
provided to the City of Edmonds. The Revision 1 Review found several prior comments were not addressed and
provided additional comments and recommendations regarding the updated design and long-term durability of
the structure. Therefore, updated calculations, civil plans, and shoring plans were provided by CG Engineering.
The following review is for the updated calculations and plans for the soldier pile shoring wall along 72nd
Avenue on the project.
Changes to the design include precast concrete lagging for the portion of wall adjacent to 72nd Avenue.
Additional calculations and shoring plan details were provided that are in general conformance with the design
specifications, criteria, and geotechnical recommendations.
Previous Comments #1 and #3 on the design calculations have still not been completely addressed in
accordance with the reviewer's recommendations. Comment #1 states that the timber lagging shall account for
traffic surcharge due to the proximity of traffic or construction operations. Comment #3 recommends that the
timber lagging design not include the benefit of soil arching. It is unknown if the intent of the concrete lagging
was for the portion of wall adjacent to traffic, and therefore the timber lagging does not need to consider live
load surcharge. However, it is feasible that the portion of wall with timber lagging may experience traffic
surcharge or construction operations that should be accounted for in the lagging design.
Even though both design calculation comments (mentioned above) have not been addressed, the timber
lagging specified in the shoring plans are oversized compared to the design calculations. Independent
calculations performed by the reviewer show that the timber lagging is sufficient for the traffic surcharge loads
and lateral earth loads without the benefit of soil arching. The Structural Engineer shall confirm the timber
lagging design and update as necessary.
The shoring wall is in general conformance with the design specifications and recommendations. Additional
reviews of the shoring wall plans or calculations are not necessary unless changes or revisions occur to the
design. If you have any questions, please don't hesitate to contact me at 509.232.8663 or
becca.boggan@deainc.com.
14432 SE Eastgate Way Suite 400 Bellevue Washington 98007 Telephone: 425.519.6500 Facsimile: 425.519.5361
DATE: August 26, 2019 FROM: Rebecca Boggan, PE
TO: Jen Machuga SUBJECT: Larsen 3-Lot Short Plat — Shoring
Wall Review
Sincerely,
qskor b
Rebecca Boggan, PE
Attachments/Enclosures: None
File Path: P:\C\COED00000013\0600INFO\EB\Shoring Wall Review_Update2\Shoring Wall Review 3 Memo.docx
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