The URL can be used to link to this page

Home My WebLink AboutCT 03-06; BLACK RAIL 16; PAVEMENT DESIGN; 2007-05-04- GeoTek, Inc. .r, '- 1384 Poinsettia Avenue, Suite A,Vista, CA 92081-8505 760-599-0509 Office 760-599-0593 Fax www.geotekusa.com May 4, 2007 Project No.: 3103SD3 Transwest Housing 10721 Treena Street, Suite 200 San Diego, California 92131 I Attention: Mr. Paul O'Boyle Subject: Pavement Design Black Rail TM No. 2-026 Carlsbad, California References: S Preliminary Geotechnical Investigation, Proposed 17-Lot Subdivision, Black Rail Road, Carlsbad, prepared by Vinje & Middleton Engineering, Inc., dated May 22, 2003. Improvement Plans For BlackRail - 16, 6 Sheets, prepared by Excel Engineering, dated 6/16/06. Dear Mr. O'Boyle: In accordance with your request we are providing herewith our pavement design recommendations for Zephyr Court and Black Rail Road in Carlsbad, California. SUBGRADE CONDITIONS R-Value testing, in general accordance with Department of Transportation, State of California, Materials & Research Test Method No. 301, was performed on representative soil samples collected from various locations within the proposed road subgrade. R-values ranged between 9 and 40. PAVEMENT DESIGN Traffic Indices (TI) of 4.5 for Zephyr Court and 6.0 for Black Rail Road, as shown on the improvement plans prepared by Excel Engineering conform with the City of Carlsbad Structural Section of Streets and Alleys. GEOTECHNICAL I ENVIRONMENTAL J MATERIALS Transwest Housing 5/4/2007 Pavement Design Project No.: 3103SD3 Zephyr Court Page 2 of 4 The table below presents our recommendations for pavement design sections. The pavement section is calculated based on the design standards presented in the California Department of Transportation "Highway Design Manual", fifth edition. k. PAVEMENT SECTIONS-AC- Street Name Traffic Index R-Value Pavement Section (Inches) Zephyr Court - 4.5 9 4 AC / 5 AB Sta. 0+00 to 4+75 Zephyr Court 45 40 4 AC /4 AB Sta. 4+75 to 6+70 Black Rail Road 6.0 40 4AC/6AB Sta. 31+55 to 35+44 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'. SUBGRADE PREPARATION Where road subgrade is in cut areas or in areas not requiring 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 top 12 inches of the subgrade and all aggregate base should be properly moisture conditioned to near 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. 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 additional or remedial work if necessary. The contractor should provide this firm with a minimum 50-pound sample of aggregate base material proposed for use at the site at least two working days prior to a request for compaction testing. If the sample is not provided or if the base materials are (in our judgment) GEOTECHNICAL I ENVIRONMENTAL I MATERIALS Transwest Housing 5/4/2007 Pavement Design . Project No.: 3 103 SD3 Zephyr Court Page 3 of 4 not represented by the sample provided, then final results of compaction testing would not be available until laboratory testing is completed. If compaction testing of the asphalt were requested, this firm would utilize the laboratory density determination from the batch plant for evaluating relative compaction. The contractor should have this information available for our representative. 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 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. Provided the pavement design recommendations contained in this report are utilized during construction, it is our opinion that the proposed street improvements for the subject street can be considered adequate for their intended use from a geotechnical viewpoint. GEOTECHNICAL I ENVIRONMENTAL j MATERIALS Transwest Housing 5/4/2007 Pavement Design Project No.: 3103SD3 Zephyr Court Page 4of4 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, GeoTek, Inc. ESSij Co Exp OF ,John A. Drake, GE. 285, Exp. 3/31/08 Senior Engineer Distribution: (4) Addressee Enclosures: R-value Test Results G:\Projects\Projects 3000 to 3999\Projects 3100 to 3 149\3 103SD3Transwest Black RailVpvmt dg.doc GEOTECHNICAL I ENVIRONMENTAL I MATERIALS MINIMUM STRUCTURAL SECTION IN INCHES TI 1.35 (EWL) TI. 4.5 5.0 6.0 7.0 8.0 8.5 9.0 TYPE CUL-DE- SAC LOCAL STREET COLLECTOR " LIGHT INDUSTRIAL SECONDARY ARTERIAL MAJOR ARTERIAL PRIME ARTERIAL SUBCRADE R-VALUE AC AB AC ABAC AB AC AS 'AC' AB AC AB AC AB 8 4 7 413.415 10 4 5 - 4 18 5 18 6 18 12 4 6 4 12 4' 14 14 - 4 17 5 17 6 17 16 4 4 4 11 4 13 5 j 16 6 16 18 ,' 45,. . 4 10 4 12 . 4 4 9411414 4 8 4 10 . . 4 7 4 9 . . ' 4 64 8 . . . . . . 46. -_ 416 20 4 15 5 15 6 15 22 614 24 514 26 5 13 6 13 28 4 13 30 5 12 6 12 32 4 1 12 6 11 34 11 5. 11 36 610 38 4 10 5 10 6 9 40. 5 ' 42 4 9 6 8 44 . 58. 48 67 48 5766 4756 52 r514 SOILS HAVING AN R VALUE LESS THAN 12 REQUIRE SPECIAL. CONSIDERATION. AN ALTERNATIVE TO INCREASING THE STRUCTURAL SECTION IS TO TEST FOR LIME STABILIZATION. THE CORRESPONDING STRUCTURAL SECTION DETERMINED AND % LIME ESTABLISHED. A.B. = ALL AGGREGRATE BASE MATERIALS SHALL BE CLASS II. PER CALTRANS SECTION 26-1.02A OR 0MB PER SECTION 200-2.4 SSPWC. THE BOTTOM FIGURES LISTED ARE THE MINIMUM PERMITTED. TOP 12" OF SUB-GRADE TO BE 95% COMPACTION. 5. PAVING SHALL BE DONE IN A MINIMUM OF TWO LIFTS WITh THE SURFACE COURSE DONE JUST PRIOR OCCUPANCY.' THE BASE COURSE SHALL BE 2.5" MIN. 6. POTABLE, RECLAIMED WATER AND GAS, VALVE BOXES SHALL BE RAISED TO GRADE OR MADE ACCESSIBLE AT EACH PAVING LIFT AS APPROVED BY THE CITY ENGINEER. IF THE SEWER MAIN IS IN SERVICE, THE ACCESSHOLE SHALL BE RAISED TO AT EACH PAVING LIFT. RAISING APPURTENANCES TO FS BEFORE AC CAP WILL NOT BE ALLOWED. RAISING VALVE BOXES, CLEANOUTS OR ACCESSORIES TO FINISH GRADE BEFORE FINISH AC CAP IS PLACED WILL NOT BE ALLOWED. REV. APPROVED DATE CITY OF CARLSBAD , .-.--.-. 6-04 STRUCTURAL SECTION. cm,' ENGINEER DATE 'OF STREETS ANDALLEYS GS-17