HomeMy WebLinkAboutCT 04-14A; TRAILS END; REVIEW OF INTERLOCKING PAVER DESIGN FOR PLANNED ACCESS ROAD; 2019-09-19Geotechnical C Geologic C Coastal C Environmental
5741 Palmer Way C Carlsbad, California 92010 C (760) 438-3155 C FAX (760) 931-0915 C www.geosoilsinc.com
TECHNICAL M EM 0 RAN DU M
Date: September 19, 2019
To: Donna Drive, LLC
5505 Canca De Golf
Rancho Santa Fe, California
Attn: Mr. Dan Hayden j
W
From: Robert C. Crisman, CEG 1934
David W. Skelly, RCE 47857
Exp. 3-31-20
W.O. 6635-E-SC
No, RCE 4'
* \Exp. —1-L- L, *
OFC&
Subject: Review of Interlocking Paver Design for Planned Access Road, Trails
End Development, CT 04-14, Northwest Corner of the Donna Drive and
Carlsbad Village Drive Intersection, Carlsbad, San Diego County,
California
References: 1. "Review of Pavement Design, Trails Lane (Private), Trails End Development, CT 04-14,
Northwest Corner of the Donna Drive and Carlsbad Village Drive Intersection, Carlsbad,
San Diego County, California," dated August 9, 2018, by GeoSoils, Inc.
2."Geotechnical Discussion and Review, Retaining Wall Drainage and Permeable Pavement
Design/Construction, Proposed Trails End Development, Northwest Corner of the Donna
Drive and Carlsbad Village Drive Intersection, Carlsbad, San Diego County, California, W.O.
6635-A-SC, Dated March 20, 2014, by GeoSoils, Inc.
3. "Geotechnical Update Evaluation, Proposed Trails End Development, Northwest Corner
of the Donna Drive and Carlsbad Village Drive Intersection, Carlsbad, San Diego County,
California," W.O. 6635-A-SC, dated November 27, 2013, by GeoSoils, Inc.
In accordance with your request, GeoSoils, Inc. (GSI), has evaluated soil subgrade and
pavement design/construction for the planned access road at the site. Unless specifically
superceded herein, the conclusions and recommendations presented in Reference Nos.
1 and 2 remain valid and applicable.
It is our understanding that pavement for the planned access road will consist of
interlocking payers able to support an AASHTO "H-20" load (i.e., fire trucks, service trucks,
etc.). Based on our review and analysis, including the minimum AASHTO load criteria, the
following paver section design and construction recommendations are provided.
The exposed subgrade soil should be scarified, moisture conditioned, and
compacted to a minimum relative compaction of 95 percent, and near optimum
moisture content, per ASTM D 1557.
The structural section should consist of the paver and underlying leveling coarse
of sand overlying a minimum 8 inches of compacted aggregate base. The sand
leveling course thickness and gradation shall be per the manufacturers
specifications.
The minimum relative compaction required for base rock will be 95 percent of the
laboratory maximum density as determined by ASTM test designation D 1557. As
required, base aggregate shall be in accordance with: Section 26 of Caltrans
Standard Specifications for Class II aggregate base; or Section 200-2.2 for crushed
aggregate base, or section 200-2.4 for crushed miscellaneous base, in the Standard
Specifications for Public Works Construction (Greenbook).
A concrete "transition" strip, "edge restraint," or "divider" should be provided
between the payers and the adjacent ground. The transition strip should be at
least 4 inches wide, with a depth equal to the total thickness (depth) of the paver
and base section.
The pavement subgrade is not anticipated to readily infiltrate any surface water that
may migrate through the payers into the underlying base. As such, a subdrain
should be considered along the down gradient edge of the paver section, where the
pavement abuts (transitions to) the planned "grasspave" pavement. The subdrain
shall consist of a minimum 4-inch diameter perforated PVC pipe (SDR 35, or
equivalent) embedded within, and not more than 1 inch from the base of the
"structural" or aggregate base layer. The subdrain should be properly outlefted to
a suitable discharge area.
For improved pavement performance, a woven geotextile (Mirafi HP 570, or
equivalent) may be placed on the subgrade surface prior to base placement.
The conclusions presented herein are professional opinions. These opinions have been
derived in accordance with current standards of practice, and no warranty is express or
implied. Standards of practice are subject to change with time. GSI assumes no
responsibility or liability for work or testing performed by others, or their inaction, or work
performed when GSI is not requested to be onsite, to evaluate if our recommendations
have been properly implemented. Use of this report constitutes an agreement and
consent by the user to all the limitations outlined above, notwithstanding any other
agreements that may be in place. In addition, this report may be subject to review by the
controlling authorities.
Distribution: Addressee (email)
Donna Drive, LLC
Trails End, Carlsbad
File: e:\wp9\6600\6635e.pdr.access GeoSods, Inc.
W.O. 6635-E-SC
September 19, 2019
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