HomeMy WebLinkAboutCT 00-06; BRESSI RANCH; UTILITY SERVICE ACCESS ROADS PAVEMENT SECTION; 2005-04-20Leighton and Associates, Inc.
A LEIGHTON GROUP COMPANY
April 20, 2005
To: Lennar Communities
1525 Faraday Avenue, Suite 300
Carlsbad, California 92008
Attention: Mr. Sean Scholey
Urc4cth1ifl0O9-O 17
CITY OF CARLSBAD
APPROVED
0 WITH ADDITIONS
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- BY DATE
Subject: Utility Service Access Roads Pavement Section, Bressi Ranch, Carlsbad, California
Introduction
This letter presents our preliminary pavement design recommendations for the utility service access
roads adjacent to Poinsettia Lane and El Fuente Street within the Bressi Ranch project, located in
Carlsbad, California. Based on the laboratory R-Value test results of the adjacent streets, we
assumed that the access roads have a representative R-Value of 14. In addition, we have assumed a
Traffic Index of 5.0 for the access roads since the roads will have minimal traffic.
Pavement Section Utilizing Fill Depth AC or Class 2 Aggregate Base Material
Based on the above information, the recommended full depth AC and Class 2 Aggregate Base
pavement sections were calculated using the Caltrans Highway Design Manual Method and
compared with the City of Carlsbad's minimum section thickness requirements. The
recommended alternative pavement sections are presented on Table 1.
Prior to placement of the aggregate base material and/or AC, the upper 12 inches of subgrade soils
in the roadway (including 6-inches behind the curb and/or gutter, if present) shall be scarified,
moisture-conditioned (or dried back) as necessary to at least optimum moisture content, and
compacted to a minimum 95 percent relative compaction based on American Standard of Testing
and Materials (ASTM) Test Method D1557.
3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425
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Table 1
Recommended Pavement Section Utilizing Class 2 Aggregate Base
Asphalt Class 2
Location Traffic Design Concrete Aggregate Base
Index R.-Value Thickness Thickness
(inches) (inches)
7.0 0.0
Utility Service Access Roads 5.0 14
4.0 6.0
If Class 2 Aggregate Base is to be used, it shall then be placed and compacted at a minimum 95
percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base
material shall be a maximum of 6 inches thick below the curb and gutter (if present) and extend a
minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall conform to and
be placed in accordance with the latest revision of the California Department of Transportation
Standard Specifications (Section 26), the Greenbook specifications, and/or the City of Carlsbad
requirements. Asphalt Concrete shall conform to and be placed in accordance with the
"Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad
requirements.
If pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be
taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or
other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade.
If you have any questions regarding our letter, please contact this office. We appreciate this
opportunity to be of service.
Respectfully submitted,
LEIGHTON AND ASSOCIATES, IN
!l K. bEGl6l2 CERTIFIEDÜ'No. 1612 m '*
Senior Associate ENGINEERING
Distribution (2) Addressee OF CALVE
Lennar Communities, Attention: Mr. Jim Urbina
City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt F
(1) J. T. Kruer, Attention: Mr. Steve Lobaugh
-2- Leighton