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HomeMy WebLinkAboutCT 00-13; TABATA PROPERTY; FLEXIBLE PAVEMENT RECOMMENDATIONS; 2003-04-02CT 00 - EOCON 34I?\ IN CJ HP ORATED GEOTECHNICALCONSULTANTS VO Pro ect j 3 :. APR /LF CAR LSD. LI NEERING DEPARTMENT Lucas & Mercier Development, Inc 630 Alta Vista Drive Suite 203 Vista California 92084 Attention: Mr. Alex Mercier • . S S Subject: TABATA CARLSBAD, CALIFORNIA. ..• FLEXIBLE PAVEMENT RECOMMENDATIONS Gentlemen In accordance with your request we have prepared this letter to provide recommendations for asphalt concrete pavement sections for the subject project Laboratory R-Value 4ests have been performed on samples of the materials piesent at subgidde elevation for Songbird Avenue Thrasher Place and Elegant Tern Place The tests were performed in general conformnc ae with ASTM Test Method D ,.2844-94, (California Test Method 301) Recommendations provided herein are based on the laboratory test results. The 'project improvement plans are entitled Improvement Plans For: Cam isbad 1r act 00 13 prepared .0' Day Consultants with City of Carlsbad date of August 26.2002. . .' The on site materials consist piedominantly of a silty sand with trace clay with a "very ,16W' to low e\pansion potential and"low" to very low R Value It is our opinion that the use of lime treatment Jo increase the R-Value of the subgrade soils to above 12, per the current pOliyof the City of Carlsbad will not be necessaiy due to the presence of silty material and the low-expansion laboratory test results. Based on peisonal communication with Mr. Donald Moore with the City of Carlsbad the lime treatment of suhgrade soils can be waivèdif the aggregate base thicliiess is increased; The City of Carlsbad s Minunumn Structural Section Standa, d GS-1 7 was used in determining the pavement sections . . . . . . FLEXIBLE PAVEMENT RECOMMENDATIONS 1. The following table summarizes the streets to be paved, the results of the laboratoiy R-Value tests, and the recommended thickness of asphalt concrete and base materials. ATraffiç Index. " (40* (TI) of 5.0 was be used for Songbird Avhué and 4.5, for Thrasher Place and Elegant Tem. Place as provided by O'Day Consultants Our recommendations are based on the procedures outlined in California Department of Transportation Highway Design Manual; Section 608.4, and the recommended pavement sections provided herein should becorisidered preliminary until final approval by thb City of Carlsbad. Calculations are provided. on Attachments 1, 2, and 3 for rview. 6960 FlandersDrie 0 San Diego, California 92121-2974 0 Telephone (858) 558-6900 • Fax(858) 558-6159 FLEXIBLE PAVEMENT SECTIONS . . . TUaffic .Laboraio.ry ••: Asphalt Concreté. '.. Class 2 Location Index R Value (inch) Aggregate Base (TI) Test Result (inches) Songbird.Avenue • 50 . . W. ,. 4 . Thrasher Pe .. 4 5 7 4 7 lac ,ElegntTthP1èè. •: 45 23 ,...' • . 4 .. 6 2 The specifications for asphalt concrete and aggregate b a s e m a t e n a l s s h o u l d c o n f o r m t o t h e most recent requirements of the City of Carlsbad 3 Prior to placing base material, the subgrade soils should be scarified, moisture con d i t i o n e d and i ecompacted to a dry density of at least 95 percent of the laboratory maximum dry density at or slightly above m optimum oisture content as determined by ASTM D 1 5 5 7 - 0 0 The depth of compaction should be at least 12 inch e s S i m i l a r l y t h e b a s e m a t e r i a l s h o u l d b e compacted to....dry density of at least 95 percent of the laboratory maximum dry density at or slightly above optimum moisture content as determined b y A S T M D 1 5 5 7 - 0 0 . 4 The performance of asphalt and concrete pavements i s h i g h l y d e p e n d e n t u p o n p r o v i d i n g positive surface drainage away from the edge of paveme n t s P o n d i n g o f w a t e r o n o r a d j a c e n t to the pavement will likely result in satuiation of t h e s u b g i a d e m a t e r i a l s a n d s u b s e q u e n t pavement distress Jf.yo haveany questions egardirg this report, or if ve m a y b e o f f u r t h e r s e r v i c e , p l e a s e c o n t a c t . t h e undersigned at yourconvenience. • : • •• • • Very truly your, • • . . •. .• •• • • : • • . • GEOCON INCORPORATED ... • • • Qdack kCE .63291 151-24 iNGINEERING JH SR dmc Attachments: Calculations . • • . (2) Addressee • . . • . •. • ATTACHMENT 3— CAL C U L A T I O N S Elegant Tern Place Use subgradeR-Value = 23 Traffic Index (TI) = 4.5 Methodology CALTRA N S H i g h w a y D e s i g n M a n u a l S e c t i o n 6 0 8 . 4 Safety Factor = 0.2 - 'Applied to Asphalt Concr e t e ( A C ) GE for AC =('0.0032)(45)(10048)+0.2 =.52 feet from Table 608.4B High w a y D e s i g n M a n u a l w i t h G F f o r A C = 2.50 GE = .52 feet for AC yields ac t u a l t h i c k n e s s = 2.50 inches Use 4.0 inches of AC .- City Minimum GE for 4.0 inches of AC = .83 feet GE for base = (0.0032)(4.5)(100-23) -.83.=.28 feet from Table 608.413 High w a y D e s i g n M a n u a l w i t h G F f o r C l a s s 2 b a s e = 1.1 Base thickness = 104 inc h e s Use base thickness = 6.0 inches (City 'Minimu m ) ***Design Street Struc t u r a l S e c t i o n Asphalt Concrete Thic k n e s s = 4.0 inches. Class 2 Aggregate Base T h i c k n e s s = 6.0 inches. Project No. 06542-52-03