HomeMy WebLinkAboutEngineering Consultation and Project Management ReportsJune 19, 2024
Andover Management Group
333 East Main Street, Suite 300
Louisville, KY 40202
Attention: Dan Kunau
Subject: Import Soils
T CTL ITHOMPSON
Founded In 1971 , ,:-,:·-.. :.\ ..
Glenwood Business Center, Lot 2, Building A
214 Center Drive
Glenwood Springs, Colorado
CTLIT Project No. GS06693.001 F-399
CTLIThompson, Inc . (CTLIT) is currently providing construction observation and materi-
als testing services during construction of Building A on Lot 2 of the Glenwood Business Center
located at 214 Center Drive, Glenwood Springs, Colorado. We previously performed a geotech-
nical engineering investigation for the project under our Project No. GS06693.000-125 (report
dated August 22, 2022). We have been asked to opine on the use of silty sand with gravel and
cobbles being imported in lieu of Class 6 aggregate base course for use as structural fill below
the retaining walls at Building A. The geotechnical engineering investigation report recommends
an 18-inch thickness of densely-compacted, Class 6 aggregate base course below footings in
order to design for a bearing capacity of 3,000 psf. The imported soils consist of a rust-colored
silty sand with gravel and cobbles.
The soils being imported to the project do not meet the specifications for Class 6 aggre-
gate base course. Sheet S100 of the Citadel Self Storage drawings by AO Drafting, Inc . (dated
March 1, 2024) states "Use 18" thick 1 Oft wide Imported Aggregate base course centered at the
Retaining wall footings ." The imported soils may be used in lieu of Class 6 aggregate base
course below the retaining wall. In our opinion a bearing capacity of 3,000 psf is appropriate for
the imported soils placed as structural fill below the retaining wall. A bearing capacity of 2,000
psf should be used for design of building foundations unless at least 18 inches of densely-com-
pacted, structural fill consisting of a material that meets specifications for a Class 6 aggregate
base course is placed below the building foundation elements.
Structural fill should be placed in loose lifts of 8 inches thick or less, moisture-condi-
tioned to within 2 percent of optimum moisture content, and compacted to at least 98 percent of
standard Proctor (ASTM D 698) maximum dry density. Moisture content and density should be
checked by a representative of CTLIT during placement. Observation of the compaction proce-
dure is necessary .
Please contact us if you have questions or need additional information.
CTLITHOMPSON, INC . , .. ✓.-<,
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Craig A. Burger,
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CTLIThompson, Inc .
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Denver , Fort Collins , Colorado Springs, Glenwood Springs , Pueblo , Summ it County -Colorado
Cheyenne , Wyoming and Bozeman, Montana
June 24, 2024
Andover Management Group
333 East Main Street, Suite 300
Louisville, KY 40202
Attention: Dan Kunau
Subject: Organic Materials in Stockpiles
T CTL ITHOMPSON
Glenwood Business Center, Lot 2, Buildings A and C
214 Center Drive
Glenwood Springs, Colorado
CTLIT Project No. GS06693.001 F-399
CTLIThompson, Inc. (CTLIT) is currently providing construction observation and materi-
als testing services during construction of Buildings A and C in the Glenwood Business Center,
Lot 2 at 214 Center Drive, Glenwood Springs, Colorado. We have been asked to opine on the
suitability of stockpiled soils for use as fill and backfill on the project.
The stockpiled soils were observed to contain some organic material. The soils were ex-
cavated after removal of the top layer of topsoil and vegetation from the project. Our representa-
tive obtained two samples (samples designated "East Topsoil Stockpile" and "North Topsoil
Stockpile") from the stockpile that were analyzed in our soils laboratory for total organic content
per ASTM D2974 "Standard Test Methods for Determining the Water (Moisture) Content, Ash
Content, and Organic Material of Peat and Other Organic Soils".
The East Topsoil Stockpile sample contained 3.4% and the North Topsoil Stockpile con-
tained 4.3% total organic content. We recommend total organic content of less than 2% in fill
and backfill. The soils in the stockpiles may be used as fill and backfill on the project if the soils
are mixed at a ratio of 1 to 1 with other soils that do not contain appreciable amounts of organic
matter. These soils should not be used in lieu of Class 6 aggregate base course where specified
by the structural engineering plans.
Please contact us if you have questions or need additional information.
CTLITHOMPSON, INC. Reviewed by:
CTLIThompson, Inc .
Denver, Fort Collins, Colorado Springs , Glenwood Springs, Pueblo, Summit County -Colorado
Cheyenne , Wyoming and Bozeman , Montana