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HomeMy WebLinkAboutCT 02-27; LA COSTA FAIRWAYS; PAVEMENT DESIGN RECOMMENDATIONS; 2005-08-26' 1384 Poinsetta Ave., Suite A / Vista, CA 92081-8505. (760) 599-0509 FAX (760) 599-0593 EK9 INC. Geotechnical Environmental Materials August 26, 2005 PROJECT No.: 2611 S133 PAR DEVELOPMENT 421 C Street, Suite 300 San Diego, California 92101 Attention: Ruben Carillo Subject: Pavement Design Recommendations La Costa Fairways Camino Abierto Sitio Carlsbad, California References: > Preliminary Geotechnical Evaluation Report by GeoSoils, Inc. dated October 8, 2002. > Supplemental Geotechnical Evaluation for Proposed La Costa Fairways Residential Project, Carlsbad, California, by Geotek, Inc., dated June 10, 2005, Project No. 2611SD3. > Grading Plans for La Costa Fairways, by O'Day.Consultants, print date May 4, 2004. Dear Mr. Carillo In accordance with your request, we are providing herewith our pavement design recommendations for the subject street at the La Costa Fairways development in the City of Carlsbad, California. STREET SUBGRADE CONDITIONS As per the referenced soils reports and based on our field observations during the on-going site grading, the subgrade materials for the subject interior street is generally comprised of clayey sand with silt. The results of the laboratory testing on a representative soil sample collected from the street subgrade of Camino Abierto Sitio indicate anR-value of 7. The R- value testing was performed in general conformance with the latest revisions to the Department of Transportation, State of California, Materials & Research Test Method No. 301. PAVEMENT DESIGN RECOMMENDATIONS Table below presents our recommendations for pavement design based on a Traffic Index (TI) of 4.5 in accordance with the street design criteria of the City of Carlsbad. The Traffic ARIZONA . CALIFORNIA IDAHO NEVADA P August 26, 2005 AR DEVELOPMENT Pavement Design Recommendations Project No.: 2611SD3 La Cos7ta Fairways - Camino Abierto Sitio Page 2 of 3 Index should be verified as necessary by the project civil engineer. The pavement section is calculated based on the design standards presented in the California Department of Transportation "Highway Design Manual", fifth edition. PAVEMENT DESIGN - Street Name Traffic R-Value Pavement Secfioñ (Inches) Calculated .1 City Index Section Minimum Camino Abierto Sitio 4.5 7 3 AC / 8 AB' C / 64 AC is asphalt concrete conforming to Section 39 of Caltrans General Specifications. AB is aggregate base conforming to the requirements of Caltrans 'Class II Aggregate Base'. Please note that the thicker of the above sections should be used in construction. SUBGRADE PREPARATION Where street subgrade is in cut condition or does not require additional fill, the subgrade should be scarified to a depth of 12 inches and large size rocks (greater than 6 inches) should removed or broken up. Subsequently, the upper 12 inches of the subgrade and all aggregate base should be properly moisture conditioned to at least optimum moisture content and compacted to a minimum relative compaction of 95 percent of the laboratory dry density as determined by ASTM Test Method D 1557-00. If adverse- conditions are encountered during preparation of subgrade materials additional measures may be required such as undercutting and removal of unsuitable subgrade materials. CONSTRUCTION OBSERVATION AND TESTING Subgrade preparation should be observed and tested by a representative of this office to check for compliance with the recommendations of this report and to assure that the soil conditions are consistent with those described herein. The subgrade observation and testing should be performed while equipment and manpower are available to perform remedial work if necessary. The contractor should provide this firm with a minimum 50-pound sample of aggregate base material at least two working days prior to a request for compaction testing. If the sample is not provided or if the aggregate base materials are (in our judgment) not represented by the sample provided, then final results of compaction test on the material would not be available until laboratory testing is completed. If compaction testing of the asphalt concrete is requested, we will utilize the laboratory density determination from the batch plant for evaluating relative compaction. The contractor should have this information available for our represetitative. 4 c/5/M PAR DEVELOPMENT August 26, 2005 Pavement Design Recommendations Project No.: 2611SD3 La Costa Fairways - Camino Abierto Sitio Page 3 of 3 PAVEMENT CONSTRUCTION AND MAINTENANCE Recommended pavement sections are meant as minimums. If thinner or highly variable pavement sections are constructed, increased maintenance and repair could be expected. Positive site drainage should be maintained at all times. Water should not be allowed to pond or seep into the ground. If planters or landscaping are adjacent to paved areas, measures should be taken to reduce the potential for water to enter the pavement section. If the ADT (average daily traffic) or ADTT (average daily truck traffic) increase beyond that reflected by the traffic indices used for design, increased maintenance and repair could be required for the pavement section. REPORT LIMITATIONS The materials encountered on the project site and utilized in the laboratory testing are believed to be representative of the total area; however, soils may vary in characteristics from one location to another to area. Since our recommendations are based on site materials observed, selective laboratory testing, and engineering analyses, our conclusion and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice and no warranty is expressed or implied. Standards of practice are subject to change with time. GeoTek, Inc. assumes no responsibility or liability for work, testing or recommendations performed or provided by others. The opportunity to be of service is greatly appreciated. If you have any questions concerning this report or if we may be of further assistance, please do not hesitate to contact the undersigned at your convenience. Respectfully Submitted, EE GeoTek, Inc. ,% cc LU 2248 Exp 10/31/05 1 William R. Morrison, Paul J. DeRisi rey P. GE 2468, Exp. 12/31/06 Staff Geologist CEG 2248, Exp.' l0/31/ Senior Engineer Geotechrncal Department Manager Distribution: (4) Addressee G:\Projects\Projects 2000 to 2999\Projects 2600 to 2649\2611SD3'ParLa costa2611 - pavementdesign'.doc CD UJ No. 8)' Exp. 12/31,b OMOEK, INC.