07-08-2019-mock-residence-retaining-wall-reconstruction-18b291-01-field-report-geotechnical-consulting-report-f208799 (1)MTC
Materials Testing & Consulting, Inc.
Geotechnical Engineering & Consulting • Special Inspection • Materials Testing • Environmental Consulting
Mock Residence Retaining Wall Reconstruction - 1813291-01 - Field Report:
Geotechnical consulting: Report #F208799
CLIENT Darrin Mock DATE
PROJECT LOCATION 21100 88th Place West Edmonds WA PERMIT #
Inspection Information:
Inspection Date: Time Onsite: 8:30 Weather Sunny, 60s, dry
07/08/2019 AM Conditions:
Inspection Performed: Geotechnical consulting
Comments:
07/08/2019
MTC visited the site as requested by the client to verify native subgrade for the new retaining wall footing, and to verify
pin pile installation to refusal of required piles done to date.
At this time, the contractor had excavated for the new block wall foundation from near the edge of the overhanging
structure south to the end of the wall planned to extend along the exterior patio south of the house. Exposed soils at the
cut elevation consisted of undisturbed and compacted native glacial till, generally light brown silty sand with gravel.
MTC noted minimal penetration up to — 1/2" maximum with a standard T-probe. We confirmed the subgrade as prepared
as suitable for direct support of a cast -in -place concrete strip or grade beam foundation which will in turn support the
small block geogrid wall. The contractor had also installed a series of 2" steel pin piles in this area as added support
which were driven partially through the till subgrade. We agreed these elective piles were suitable to remain below the
wall footing alignment.
The first four pin piles were also installed for the block wall that will be topped with a structural slab tied into the existing
house foundation in the vicinity of the house overhang. MTC observed the contractor proof -test these piles by redriving
to verify refusal criteria were met. A hand -operated pneumatic hammer was used at full force. Less than one inch of
penetration was observed for 60 seconds of sustained driving, consistent with the recommended and typical refusal
criteria for the pile size and capacity required. Approximate pile embedment as determined by the contractor's
information and direct measurements is recorded below (from current grade):
Pile 1: T-3"
Pile 2: T-Y
Pile 3: T-10"
Pile 4: T-10"
MTC agreed to return for further inspections of wall foundation and pile install preparations once the project progresses
into the overhang area.
While on site, the client/contractor discussed needing to use varying wall heights versus the original plan, and we were
shown a schematic of approximate foundation versus final grades for the wall extending along the SW corner and south of
the house. MTC agreed to evaluate modifications to the design geogrid length at request of the client for wall heights
exceeding the original plan height. At this time the top -of -foundation elevation is still to be determined between the
client and structural engineer.
To the best of MTC inspector's knowledge, the above -described work was performed in general accordance with project
specifications and approved plans.
Images:
Corporate • 777 Chrysler Drive • Burlington, WA 98233 • Phone 360.755.1990 • Fax 360.755.1980
Regional Offices: Olympia Bellingham Silverdale Tukwila
360.534.9777 3 60.64 7.6111 360.698.6787 206.241.1974
Visit our website: www.mtc-inc.net
Mock Residence Retaining Wall Reconstruction - 1811291-01, 0710812019, #F208799, Page 1 of 2
MTC
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UPLOADED: 07/08/2019 19:44:41 End of current
trench for wall footing
Materials Testing & Consulting, Inc.
Geotechnical Engineering & Consulting • Special Inspection • Materials Testing • Environmental Consulting
UPLOADED: 07/08/2019 19:44:40
n
UPLOADED: 07/08/2019 19:44:42 Proof -testing UPLOADED: 07/08/2019 19:44:43 Looking along
installed piles back side of house toward overhang
REPORTED BY: Kevin Walters REVIEWED BY: John Gillaspy, Project Manager
Corporate • 777 Chrysler Drive • Burlington, WA 98233 • Phone 360.755.1990 • Fax 360.755.1980
Regional Offices: Olympia Bellingham Silverdale Tukwila
360.534.9777 360.647.6111 360.698.6787 206.241.1974
Visit our website: www.mtc-inc.net
Mock Residence Retaining Wall Reconstruction - 18B291-01, 0710812019, #F208799, Page 2 of 2