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Subject: Final Letter — Geotechnical Services
Edmonds Way Apartments
23014 Edmonds Way
Edmonds, Washington
�keference: Earth Solutions NW, LLC
Geotechnical Engineering Study
ES-2039, dated April 6, 2011
Earth Solutions NW, LLC
Photo and Survey Monitoring Program Docume
ES-2039.01, dated June 9, 2011 1
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In accordance with your request, Earth Solutions NW, LLC (ESNVV) provided geotechnical
monitoring and testing services during the shoring and earthwork phases of construction,
Services were provided between August 2011 and March 2012. Geotechnical monitoring and
testing included the following:
Temporary and permanent soldier pile wall installation — An ESNW representative was
onsite during the soldier pile wall installation to confirm pile embedment depths and soil
conditions. Periodic site visits were also conducted during the excavation and lagging to
confirm soil "cut face" stability. Based on our observations, the soldier pile wall installation was
completed in general accordance with the approved plans and our geotechnical
recommendations.
Coordination with project surveyor in implementation of site monitoring program
(soldier pile wall / adjacent right-of-ways and existing structures) — Prior to beginning the
site earthwork activities, ESNW met with the contractor and project surveyor to confirm
frequency and locations of survey points for the site monitoring program. Guidelines provided
in the referenced Photo and Survey Monitoring Program Document were reviewed and
implemented as applicable. Monitoring points were established along adjacent right-of-ways,
soldier piles, and existing structures (where appropriate).
1805 - 136th Place N.E., Suite 201 ® Bellevue, WA 98005 ® (425) 449-4704 ® FAX (425) 449-4711
GRE Edmonds Way, LLC PES-2039,02
April 13, 2012 Page 2
Review of survey monitoring data and confirmation of shoring wall performance —
Hansen Surveying collected the monitoring data during the'excavation and shoring phases of
construction. Baseline data (prior to the start of earthwork) were collected on July 19, 2011,
Monitoring continued through substantial completion of the earthwork. The last set of
monitoring data was collected on December 5, 2011. Periodic visual observations by the
undersigned and his representative were also performed as part of the overall monitoring
program. Based on the monitoring data and visual observations, excavation related
movements were insignificant, and generally within the horizontal and vertical positional
accuracy of the surveying instrument (0.02 feet). In this respect, the excavation and soldier pile
shoring systems demonstrated good performance.
Confirmation of building foundation subgrade and allowable soil bearing capacity —
Foundation subgrade soil was observed and tested (as necessary) to confirm acceptable
bearing conditions. The building foundation soils were observed to be acceptable for
foundation bearing and the design allowable soil bearing capacity of 5,000 psf.
Confirmation of slab -on -grade and pavement subgrade stability — Areas of pavement and
slab -on -grade subgrade were observed and tested (as necessary) to confirm stability and
acceptable support characteristics. The pavement and slab -on -grade subgrade was observed
to be acceptable for support of these structures.
Compaction testing of structural backfill soils — Compaction testing of structural fill soils
was completed as necessary during the earthwork phase of construction. Field density tests
were conducted in accordance with ASTM Test Designation D2922 (Nuclear Gauge Method).
Two representative soil samples were returned to our laboratory for analysis of the maximum
dry de . nsity and optimum moisture content in accordance with ASTM D1557-02 (Modified
Proctor). Density test results indicated an acceptable level of relative compaction at the tested
locations.
Based on our observations and testing, and to the best of our knowledge, it is our opinion the
earthwork construction was accomplished in general accordance with the approved plans and
our geotechnical recommendations.
We trust this final letter and summary of geotechnical services meets your current needs.
Should you require additional information, or have questions, please call.
Sincerely,
Raymond A. Coglas, P.E.
Principal
Bruce is (Email only)
Earth Solutions NW, LLC