HomeMy WebLinkAboutHARMONY RIDGE FILING 2 - Filed SER-SUBSURFACE EXPLORATION REPORT -August 24, 2005
Global Holdings of Colorado, LLC
932 East Pitkin Street
Fort Collins, Colorado 80524
Attn: Mr. Jim Newcomb
Re: Subsurface Exploration Report
Harmony Ridge II Pavement Design
Fort Collins, Colorado
EEC Project No. 1054056 P
Mr. Newcomb:
EARTH ENGINEERING
CONSULTANTS, INC.
A PROVED
f
Our subsurface exploration report for the roadway subgrades at Harmony Ridge Phase II
in Fort Collins, Colorado was submitted to your attention on August 16, 2005. Based on
that report, the City of Fort Collins Engineering Department has provided estimated
traffic loadings for the development streets. Pavement section recommendations are
provided in this report based on the traffic loadings provided by the City of Fort Collins
Engineering Department and the subgrade soil tests previously completed by Earth
Engineering Consultants, Inc. (EEC).
A Hveem stabilometer R-value of 11 was determined for the rough graded pavement
subgrades. Using the American Association of State Highway and Transportation
Officials (AASHTO) correlation, that R-value corresponds to a resilient modulus value of
7105. The resilient modulus value of 7105 was used in the pavement evaluation.
The AASHTO design guidelines for pavement design were used to evaluate
recommended pavement sections for this project. Recommended pavement sections
based on that evaluation are provided on the attached summary. In accordance with your
agreement with the City of Fort Collins, Portland cement concrete pavement is required
in the "bubble" around the detention pond. The other roadways could utilize the
composite section.
Consideration could be given to stabilization of the pavement subgrades through the
addition of Class C fly ash. The stabilized subgrade would enhance the long term
performance of the pavements and reduce the potential for adverse weather impacting the
4396 GREENFIELD DRIVE
WINDSOR, COLORADO 80550
970) 224-1522 FAX (970) 663-0282
I
pavement construction. The addition of 12% Class C Fly ash (based on dry weight) to
the top 12 inches of the subgrades could be considered to stabilize those subgrades. We
would be pleased to provide additional recommendations for subgrade stabilization if
requested.
The asphaltic concrete used as the surface course in the pavement area should be
consistent with City of Fort Collins classification for Grading S. The aggregate base
should be consistent with Colorado Department of Transportation requirements for Class
5 or Class 6 base. Portland cement concrete should meet City of Fort Collins
requirements for pavement concrete.
We appreciate the opportunity to be of service to you on this project. If you have any
questions concerning this report, or if we can be of further service to you in any other
way, please do not hesitate to contact us.
Very truly yours,
Earth Engineering Consultants, Inc.
Lester L. Litton, P.E.
Principal Engineer
LLL/cgw
cc: Chad Holman — c holmankcomcast.net
Jim Newcomb —-newcnverinet.com
Rick Richter — City of Fort Collins (4 copies)
TABLE I: PAVEMENT SECTION EVALUATION/RECOMMENDATIONS
PORTLAND CEMENT HBP/COMPOSITE
CONCRETE
Design Axle Loads (EDLA = 15) 109,500 109,500
Reliability 85% 85%
Deviation 0.34 0.44
Subgrade Resilient Modulus 7105 7105
PSI Loss 2.5 2.5
Design Structural Number N/A 2.34
Design Pavement Section 6" 4" HBP (1.76)
6" ABC 0.66
2.42)
Project: Harmony Ridge II Pavement Design
Fort Collins, Colorado
Project No.: 1054056P
Date: August 2005
E E CJ