HomeMy WebLinkAboutSUB201700074 Other 2020-06-18underhill ENGINEERING
geotechnical I geodesign I geoconstruction
June 18, 2020
Mr. John Anderson, PE, Civil Engineer II
Community Development Dept.
County of Albemarle, Virginia
401 McIntire Road
Charlottesville, VA 22902-2702
Construction Engineering and Testing Services in Pavement Areas, Hollymead Towncenter Block
VI, Albemarle County, Virginia (Underhill Engineering Project No. 18023)
Dear Mr. Anderson:
Underhill Engineering, LLC (Underhill) is pleased to present this letter, summarizing Underhill's services
for the above referenced project. These services are provided in accordance with Underhill's Service
Agreement with Town Properties, LLC dated March 1, 2016, and authorization dated April 5, 2018.
Underhill's services for the project included construction observation and testing in the new pavement
areas, including new alleys. These services included observation and testing of utility backfill,
observation of subgrades, observations of aggregate, and California Bearing Ratio (CBR) testing.
Underhill provided services for the project from June 29, 2018, through February 5, 2020. Soil
laboratory test results consisting of soil classification, Standard Proctor tests, and CBR test results were
provided to the Client in Underhill's reports dated November 28, 2018 and July 31, 2019. Following
is a summary of Underhill's test results relating to the project pavements:
■ Pavements are in areas of cut and in areas of compacted structural fill tested by Underhill.
Subgrades consisted of generally firm SILTY SAND (SM) residuum containing rock fragments.
The earthwork observation and testing of compacted structural fill placed in the pavement
areas provided by Underhill indicated that the compacted structural fill was compacted to at
least 95 percent of the maximum dry density in accordance with ASTM D698, Standard
Proctor, and in general accordance with the project documents prepared by Dominion
Engineering last revised May 8, 2017.
■ CBR testing indicated the three samples of on -site soils to exhibit laboratory CBR values of
20.1, 19.3, and 22.9, each exceeding the design CBR value of 10.
■ Pavement subgrades were proofrolled under the observation of Underhill's engineering
personnel and subgrades were considered suitable to receive compacted dense graded
aggregate.
■ Field density testing of the compacted dense graded aggregate for pavement support was
provided by Underhill. Testing indicated compaction to at least 95 percent of the maximum
dry density in accordance with ASTM D698, Standard Proctor, and in general accordance with
the project documents referenced above.
■ Measurements of the asphalt thickness were made during the asphalt placement. These
measurements indicated the asphalt thickness to be in accordance with the design pavement
section requirements as indicated in the project documents referenced above.
Based on our observations and testing, including the high CBR test results obtained, Underhill considers
the project's constructed pavement section, including for the alleys, to be suitable for the design traffic.
Hollymead Towncenter Block VI
Albemarle County, Virginia
Underhill has endeavoured to complete the services identified herein in a manner consistent with that
level of care and skill ordinarily exercised by member of the profession currently practicing in the
same locality and under similar conditions as this project. No other representation, expressed or
implied, is included or intended, and no warranty or guarantee is included in this report.
Thank you for the opportunity to provide our services. If you have any questions or require additional
information, please do not hesitate to contact the undersigned.
Sincerely,
UNDERHILL ENGINEERING, LLC
6'r, PfiP
Elliot J. White, EIT, PIMP
Staff Engineer I
O. Christopher Webster, PE
Principal
cc: Katurah Roell -Town Properties, LLC
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Project 18023 / June 18, 2020 2 Underhill Engineering, LLC