HomeMy WebLinkAboutB18-0067_Pavement Design signed_1521480169.pdf H-P-�KU mAR5020 County Road 154
Glenwood Springs, CO 81601
Geotechnical Engineering I Engineering Geology Phone: (970)945-7988
Materials Testing I Environmental Fax: (970)945-8454
Email: hpkglenwood@kumarusa.com
Office Locations: Denver(HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, Summit County, Colorado
January 25, 2018
Westwind at Vail
Attn: Jeff Jacobs
548 South Frontage Road
Vail, Colorado 81657
iiacobs@vail.net
Project No. 17-7-463
Subject: Recommendations for Pavement Section Thickness Design, Proposed Site
Improvements,Westwind at Vail, 548 South Frontage Road, Vail, Colorado
Dear Jeff:
As requested by Bill Pierce, we are providing recommendations for pavement section thickness
design at the subject site. This report provides our recommendations for the pavement section
and subgrade preparations. The services are supplemental to our agreement for geotechnical
services to Westwind at Vail dated June 9, 2017.
Background Information: H-P/Kumar previously conducted a subsoil study for design of the
proposed fitness center pool renovations at the site and presented our findings in a report dated
October 6, 2017, Project No. 17-7-463. New concrete pavement on the west and north sides of
the building are also planned. The pavement will be subjected to regular vehicle traffic including
some truck traffic, consisting primarily of trash pick-up, with occasional fire trucks. The traffic
loadings have not been provided but are assumed to be typical of the development. The concrete
pavement will be heated.
Subgrade Conditions: Our previous borings on the east side of the building encountered
primarily silty clayey sand with scattered gravel soils at shallow depths underlain by coarse
granular soils. The sand soils are assumed to be exposed at subgrade in the new pavement areas.
These soils typically have an AASHTO Classification of A-4 and are considered fair to poor
support for pavement sections, and moderately susceptible to frost heave. We assume a modulus
of subgrade reaction of 75 pci for the rigid (concrete) pavement design.
Westwind at Vail
January 25, 2018
Page 2
Traffic Loading: Since anticipated traffic loading information was not available at the time of
report preparation, an 18 kip equivalent daily load application (EDLA) of about 12 was assumed
for combined automobile and truck traffic, including fire trucks, in the pavement areas. These
loadings are typical of a similar size development driveway, and should be checked by the
project civil engineer.
Recommendations: Based on the assumed and estimated parameters, the pavement section in
areas of combined automobile and truck traffic should consist of a 61 inches CDOT Class D
portland cement concrete on 4 inches of CDOT Class 6 aggregate base course. The section
assumes a design strength of 4,500 psi for the concrete. The concrete should be air entrained.
It is feasible to place 2 inch thick rigid insulation between the base course and concrete. The
insulation should consist of heavy duty Styrofoam Brand Highload material or equivalent.
Prior to placing new pavement materials, the subgrade should be stripped of debris, topsoil,
unsuitable fill materials and any unstable soils, scarified, moisture content adjusted to near
optimum and compacted to at least 95% of the maximum standard Proctor density. Some
subgrade soil areas may be highly moist and need to be stabilized or removed. The pavement
subgrade should be proof-rolled with a heavily loaded pneumatic-tired vehicle. Pavement design
procedures assume a stable subgrade. Areas which deform excessively under heavy wheel loads
are not stable and should be removed and replaced with well graded coarse granular soils to
achieve a stable subgrade prior to paving. Backfill needed in low areas should consist of a
relatively well-graded granular soil, excluding debris and rocks larger than 6 inches, and be
compacted to at least 95% of standard Proctor density within 2 percentage points of optimum.
The collection and diversion of surface drainage away from paved areas is extremely important
to the satisfactory performance of pavement. Drainage design should provide for the removal of
water from paved areas and prevent wetting of the subgrade soils.
Limitations: The recommendations submitted in this report are based on assumed traffic
loadings and subgrade conditions from nearby borings. We did not perform subsurface
exploration to determine the subsoil conditions at the pavement areas. It is possible the data
obtained by subsurface exploration could change the recommendations contained in this letter.
We should verify the assumed subgrade conditions at the time of construction. If conditions
encountered during construction appear different from those described in this report, we should
H-PMKUMAR
Project No. 17-7-463
Westwind at Vail
January 25, 2018
Page 3
be notified at once so re-evaluation of the recommendations may be made. Significant design
changes may require additional analysis or modifications to the recommendations presented
herein. We recommend observation of subgrade conditions exposed and proof-rolling of the
subgrade, and compaction testing of structural fill by a representative of the geotechnical
engineer.
If you have any questions or need further assistance, please call our office.
Sincerely,
H-PKUMAI
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5.3 la* t• fa
David A. Young, P.E. -216 �tg ®
DAY/kswk 32
143 �'",, , rOe14
cc: William Pierce Architects—Bill Pierce (bill@vailarchitects.com)
Yarnel Engineering—Justin Yarnel (Justin@theyarnells.com)
RA Nelson &Associates—Jason Morley(imorley@ranelson.com)
Sean Reynolds (sean@vailmanagement.com)
H-PKUMAR
Project No. 17-7-463