Duke Lesley Lot 4 Blk A-CS140902 (2)
GE
EOTECHNICALNGINEERING
EC
NVIRONMENTAL ONSULTING
CMT
ONSTRUCTION ATERIAL ESTING
August 22, 2014
Mr. Michael Garza, P.E.
Assistant Director of Engineering
City of Coppell
265 Parkway Boulevard
Coppell, Texas 75019
Re:Point West VIII Fire Lane
Dividend Drive
Coppell, Texas
Rone Project Number 13-18658
Dear Mr. Garza,
Rone Engineering Services, Ltd. (Rone) has been asked to provide a letter confirming the use
of 6 inch paving for fire lanes for the referenced project. The request for this letter was
originated by Mr. Gordon Adkinson with Duke Realty, the developer of the referenced project.
In Rone’s original geotechnical report (Report number 13-18658 dated November 14, 2013)
pavement recommendations were provided on pages 11 through 15. Traffic counts (ESAL’s)
used for the design are presented on Page 11 and 12. The traffic counts assume a tractor
trailer frequency of about 20fully loaded tractor trailers per day, which includes periodic travel
by emergency servicevehicles, such as fire trucks. The list also indicates the “k” value of 100
pci used for non-lime-treated subgrade soils.
During the course of study for the site, Rone obtained samples of near surface soils to conduct
testing for the presence of solublesulfates. Results indicated an elevated risk of sulfate
induced heave due to the soluble sulfate content. Sulfate heave can be induced by the addition
of calcium rich additives to the soil, such as lime or cement, often used for subgrade
improvement. Therefore, Rone recommended lime treatment be omitted, as discussed in the
original geotechnical report. Based on our analysis, the subgrade will support the anticipated
traffic loading using the design sections provided.
Of course, as is the case with any pavement, the performance life may be shortened if proper
maintenance and construction are not completed. Positive drainage is important to prevent
ponding of water that infiltrates the pavement, and sealing of cracks will reduce the potential for
waterintrusion and subsequent subgrade softening.
D|FW|A|SA|H
ALLAS ORT ORTH USTIN AN NTONIO OUSTON