HomeMy WebLinkAboutCT 00-06; BRESSI RANCH; GEOTECHNICAL CONCLUSIONS CONCERNING THE DECOMPOSED GRANITE; 2004-10-07Leighton and Associates, Inc.
A LEIGHTON GROUP COMPANY
October 7, 2004
To:
Attention:
Subject:
Project No. 971009-011
City of Carlsbad Public Works Department
5950 El Camino Real
Carlsbad, California 92008
Mr. Casey Arndt
Geotechnical Conclusions Concerning the Decomposed Granite for the DG Trails at
Bressi Ranch, Carlsbad, California
This letter presents our conclusions concerning the decomposed granite (i.e. DG) for the DG trails within
the Bressi Ranch project located in Carlsbad, California. We understand that the contractor would like to
use a DG product called Paradise Gold. A copy of the gradation or sieve/particle-size analysis obtained
from the manufacturer of the product (attached) indicated the DG meets the project specifications. On
October 5, 2004, a sample of the material was obtained and transported to our laboratory. Based on the
results of the laboratory testing, the sample generally met the project specifications, as indicated in the
attached table. However, the sample did not meet all of the gradation percent passing requirements.
Although the sample did not meet all of the gradation requirements, it is our professional opinion that the
product is suitable for the intended use as DG on a walking trail. Therefore, from a geotechnical
standpoint, we recommend that the product be used as the DG for the Bressi Ranch walking trails. if you
have any questions regarding this letter, please contact this office. We appreciate this opportunity to be of
service.
Respectfully submitted,
LEIGHTON AND ASSOCIATES, INC.
'$ %tle,Randall
y
EG 1612
Senior Associate
Attachments: Table I - Laboratory Test Results of the DG Trail Mix
Particle-Size Analysis of the Paradise Gold DG obtained from the Manufacturer
Distribution: (2) Addressee
(2) Lennar Communities, Attention: Mr. John Slatton
(1) Lennar Communities, Attention: Mr. Jim Urbina
(1) JT Kruer, Attention: Mr. Chuck Knight
(1) Hazard Construction Company, Attention: Mr. Lino Cruz
3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425
858.292.8030 • Fax 858.292.0771 • www.leightongeo.com
971009-011
Table 1
Laboratory Test Results of the DG Trail Mix (Paradise Gold)
Sieve Analysis
Sieve Size
Operating Range Required
Percentage Passing Sample Result In Conformance?
3/8 inch 100 100 Yes______
No. 4 95-100 96 Yes
No. 8 75-80 66 No
No. 16 55-65 49 No
No. 30 40-50 37 No
No. 50 25-35 26 Yes
No. 100 20-25 19 No
No. 200 5-15 14 Yes
Atterberg Limits of Portion Passing the No. 4 Sieve
Required Maximum Sample Result In Conformance?
Liquid Limit 25 0 Yes
Plasticity Index 7 0 (non plastic) Yes
Durability of Portion Retained on the No. 4 Sieve
Maximum Percentage of Wear Sample Result In Conformance?
50 25 Yes
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- Leighton
10/01/2004 14:43 97607444814 KRC ROCK INC PAGE 02
Particle-Size Analysis Of Soils
Paradise Gold DG
SIEVE WT. RET. ACC. WT. RET. ACC.%WT.RET, PASSING .375 0 - 100 4 39.1 39.1 3.91 96.08999
8 182.3 221.4 22.14 77.86
- 16 179.4 - 400.8 40.08 59.92 30 - 150.1 - 550.9 - 55.09001 44.91
- 154.1 705 -. 70.5 29.5
100 695 - 774.5 77.45 22.55
- 200 130 904.5 90.45 9.550003
0 - 2.3 906,8 90.68 - 9.32
TNITIAL WEIGHT DRY SOIL BEFORE WAS (GMS) = 000 WEIGHT DRY SOIL AFTER WASH (OMS)
= 906.8