HomeMy WebLinkAboutRS_Geotechnical_Engineering_Review_design letterFebruary 15, 2021
Project No. T-7886
Mr. Ben Paulus
Blue Fern Development, LLC
11232 – 120th Avenue NE, Suite 204
Kirkland, Washington 98033
Subject: Geotechnical Engineering Review
Canopy
4130 – Lincoln Avenue NE
Renton, Washington
References: 1. Geotechnical Report, Canopy, 4130 – Lincoln Avenue NE, Renton, Washington,
Project No. T-7886, prepared by Terra Associates, Inc., dated March 19, 2019,
6th Revision May 18, 2020
2. Civil Drawings, Canopy, 7496 – Lincoln Ave NE, Renton, Washington,
prepared by CORE Design, dated February 15, 2021
3. Retaining Wall Designs, Canopy, 4130 – Lincoln Avenue NE, Renton, Washington,
Project No. T-7886, prepared by Terra Associates, Inc., dated February 24, 2020,
revised May 18, 2020
Dear Mr. Paulus:
As requested, we have reviewed the referenced drawings that were prepared for the project. Based on our review,
the project consists of redeveloping the site with 55 single-family residences, 2 stormwater detention vaults, 8
retaining walls, and associated access roadways and utilities. Grading to achieve the building lot and roadway
elevations will consist of cuts and fills from 1 to 16 feet. The vertical-grade transition along the east side of the
site will be supported with cut rockery and Redi-Rock wall systems. The vertical-grade transitions along the
northeast section of Road A and the western side of building lots 15 and 16 will be supported with a cut rockery.
The vertical-grade transition along the west side of Alley 3 will be supported with a planter Redi-Rock wall.
Other grade transitions will be supported with maximum 2:1 (Horizontal: Vertical) or flatter slopes.
The Redi-Rock retaining walls along the east side of Building Lots 30 – 40 have a maximum exposed height of
10 feet. Cross Section B-B’ completed for the referenced geotechnical report assessed the stability of the
excavation and retaining wall system for a 12-foot excavation. Therefore, the proposed excavation is within the
boundaries of the geotechnical report and the analysis and conclusions of the report remain valid. All 8 retaining
walls are within the design parameters as shown in the referenced retaining wall design letter and therefore are
suitable for the site and can be constructed as shown on the plans.
12220 113th Avenue NE, Ste. 130, Kirkland, Washington 98034
Phone (425) 821‐7777 • Fax (425) 821‐4334
2-15-2021