Twin Star
Northwest Testing Company, Inc.
CONSTRUCTION TESTING and INSPECTION
ENVIRONMENTAL CONSULTATION and ASSESSMENT
FIELD INSPECTION REPORT
CLIENT:DATE:
Twin Star Credit Union April 03, 2008
PROJECT:REPORT NO:
Yelm Branch Addition 01
CONTRACTOR: PROJECT NUMBER:
Schwiesow Construction 0803.6
PERMIT NUMBER:INSPECTOR:
BLD 070419 YL Mark Robinson
Inspector Mark Robinson arrives on site, 12:45 pm, for project overview with contractor and for
inspection of subgrade compaction. Sunny, 52 degrees.
Contractor has completed the excavation and yield-compaction for the four canopy footing pads. The
exposed native soil consists of loamy silt with gravel (SM). The subgrade has been yield-compacted
with the hoe-pak. While the earth appears well consolidated, inspector does note that the soil appears
to be below optimum moisture content for this soil type.
Two in-place field density compaction tests are made at randomly chosen footing locations, and a
sample of the soil is taken for moisture-density testing. Subsequent laboratory results indicate the
field tests fall below the 95% compaction requirement.
Discussion:
as was noted in Bradley-Noble’s geotechnical report for the project, it is difficult to
moisture-condition this soil type. Any water added has to be given adequate time to percolate
evenly throughout the soil prior to compaction efforts, otherwise, the soil liquefies beneath the
compactor. This makes it difficult to work the soils in inclement weather.
Rain over the weekend will have percolated through the soil and should bring the moisture
content close enough to the optimum to attain the 95% compaction requirement. If the rain stops,
the contractor is given the option of trying to mechanically re-compact the subgrade or to over-
excavate 12” and bring in compacted crushed rock or other suitable gravel that is less moisture-
sensitive. Crushed rock is recommended since it will be required later beneath asphalt areas, thus
eliminating additional laboratory proctor expenses later on.
NORTHWEST TESTING COMPANY, INC.
Mark Robinson
Mark Robinson
Licensed Professional Geologist
Registered Site Assessor
ACI/ICC Certified Concrete Technician
cc: Jeff Kennedy, Mark Schwiesow, Fred Lawson II, Gary Carlson, Brian Unsderfer, Jerry
Morrissette
PO BOX 11581 OLYMPIA, WASHINGTON 98508-1581 PHONE or FAX (360) 866-3647