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Home My WebLink AboutCT 90-03; SHELLEY PROPERTY; PAVEMENT DESIGN RECOMMENDATIONS; 2002-02-28- 10brati,,. MWANFA hL~ 1961 - 2001 Leighton and Associates GEOTECHNICAL CONSULTANTS February 11, 2002 (revised February 28, 2002) Project No. 851855-013 To: Continental Homes 2237 Faraday Avenue, Suite 100 Carlsbad, California 92008 Attention: Mr. Dave Jones Subject: Pavement Design Recommendations, Avenida Del Alba and a Portion of Avenida La Cima (Between Station No. 1+40 to 3+30 and 17+00 to 18+13), Arroyo Vista Unit 3, Carlsbad Tract No. 90-03, Carlsbad, California References: Carlsbad, City of, 1996, Standards for Design and Construction of Public Works Improvements in the City of Carlsbad, California, Project No. 05332-12-0 1, dated April 20, 1993, revised December 10, 1996 Leighton and Associates, 2002, Pavement Design Recommendations, Avenida Del Alba and a Portion of Avenida La Cima, Arroyo Vista Unit 3, Carlsbad Tract No. 90-03, Carlsbad, California, Project No. 851855-013, dated February 11,2002 Project Design Consultants, 2001, Plans for the Improvement of Shelley Property Unit No. 3, Carlsbad Tract No. 90-03, Carlsbad, California, Project No. CT 90-03, 8 Sheets, dated March 29, 2001 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our revised pavement design recommendations for Avenida Del Alba and a portion of Avenida La Cima (between Station No. 1+40 to 3+30 and 17+00 to 18+13) within Unit No. 3 of the Arroyo Vista project (Carlsbad Tract No.90-03) located in Carlsbad, California. Two subgrade soil samples (Samples R-10 and R-11) were obtained on February 8, 2002. Three additional subgrade soil samples (Samples R-12 through R-14) were obtained on February 19, 2002. The samples were transported to our laboratory and R-value testing (in accordance with Caltrans Test Method 301) was performed. The test results indicated the subgrade soils have R-values ranging between 14 and 23. The approximate sample locations and results of the laboratory testing are presented in Appendix A. Based on the project Improvement Plans (Project Design Consultants, 2001), we understand that Avenida Del Alba and Avenida La Cima are considered local streets and have a traffic index (TI) of 5.0. According 3934 Murphy Canyon Road, #B205, San Diego, CA 92123-4425 (858) 292-8030 • FAX (858) 292-0771 • www.leightongeo.com 851855-013 to the City requirements (Carlsbad, 1996), the minimum pavement section for streets having a TI of 5.0 or less (regardless of the R-value) is 4 inches of Asphalt Concrete (AC) over 4 inches of Aggregate Base (AB). Pavement Section Utilizing Class 2 Aggregate Base Material Based on the above information, the recommended Class 2 aggregate base pavement section was calculated using the Caltrans Highway Design Manual Method and compared with the City of Carlsbad's minimum section thickness requirements. The recommended pavement section is presented on Table I. The pavement section design calculations utilizing Caltrans design methods are presented as Appendix B. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Asphalt Concrete Class 2 Aggregate Traffic Design Thickness Base Thickness Location Index R-Value (in inches) (in inches) Avenida La Cima (Station No. 1+40 to 3+30) and 5.0 14 4 6 Avenida Del Alba (Station No. 20+50 to 24+00) Avenida Del Alba (Station 18+13 to 20+50 and 24+00 to 32+40) and 5.0 21 4 5 Avenida La Cima (Station No. 17+00 to 18+13) Prior to placement of the Class 2 aggregate base material, the upper 12 inches of subgrade soils in the street (including a minimum of 6 inches beyond the back of the curb and gutter) should be scarified, moisture- conditioned to at least optimum moisture content and compacted to a minimum 95 percent relative compaction based on American Standard of Testing and Materials (ASTM) Test Method D1557. Class 2 Aggregate Base should then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material should extend a minimum of 6 inches behind the back of the curb. Class 2 Aggregate Base should conform to and be placed in accordance with the latest revision of the California Department of Transportation Standard Specifications (Section 26), the Greenbook specifications, and/or the City of Carlsbad requirements. Asphalt Concrete should conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. 851855-013 Pavements Adjacent to Landscape Areas If pavement is planned adjacent to landscaped areas, we recommend that appropriate measured be taken (such as keeping the amount of landscape irrigation to a minimum), installing area drains or other devices to reduce the possible adverse effects of water on the pavement subgrade. If you have any questions regarding our report, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, < OFESSi L IGHTON AND ASSOCIATES, INC. ZO EXP. 12J31103 C/Vl\. Director of Engineering OF M0 / ) GE0 Randall K. Wagner, CEG 1612 Director of Geology Attachments: Appendix A - Laboratory Testing Procedures and Test Results Appendix B - Asphalt Pavement Section Design Calculations :;• Distribution: (8) Addressee -3- - 851855-013 APPENDIX A Laboratory Testing Procedures and Test Results "R"-Value: The resistance"R"-value was determined by the California Materials Method No. 301 for subgrade soils. Three samples were prepared and exudation pressure and "R"-value determined on each one. The graphically determined "R"-value exudation pressure of 300 psi is summarized in the table below: Sample Number and Representative Location Sample Description R-Value Location • Avenida La Cima Avenida La Cima (Station No. 17+00 to 18+13) Yellow-brown silty to Station No. 18+00 and Avenida Del Alba clayey SAND 23 (Station No. 18+13 to 20+50) Avenida Del Alba Avenida Del Alba Olive-brown silty to Station No. 25+00 (Station No. 24+00 to 28+50) clayey SAND 22 Avenida Del Alba Avenida Del Alba Light yellow brown sandy 16 Station No. 2 1+00 (Station No. 20+50 to 24+00) CLAY Avenida Del Alba Avenida Del Alba Yellow olive brown 21 Station No. 31+00 (Station No. 28+50 to 32+40) clayey SAND Avenida La Cima Avenida La Cima Light yellow brown sandy 14 Station No. 2+25 (Station No. 1+40 to 3+30) CLAY Al 851855-013 APPENDIX B Asphalt Pavement Section Design Calculations 1) Avenida Del Alba between Station No. 18+13 to 20+50 and 24+00 to 32+40 and Avenida La Cima between Station No. 17+00 to 18+13 H = Thickness GE = Gravel Equivalent Design Traffic Index = 5.0 Design Subgrade R-Value = 21° Class 2 Aggregate Base R-Value =78, (based on Caltrans Standard Specifications, Section 26) Asphalt Concrete (AC) Layer GEac = (0.0032) (5.0) (100-78) + 0.20 = 0.55 feet Gfac° 2.54 ° Hac= 0.55 feet x12 in/ft=2.6 inches 2.55 Use 4.0 inches of asphalt concrete (City of Carlsbad minimum) ° Actual GE of asphalt concrete layer = (4/12 feet) 2.54 = 0.85 feet Aggregate Base (AB) Layer GEtotai = (0.0032) (5.0) (10021) 1.26 feet ° GE AB= 1.26 feet - 0.85 feet = 0.42 feet GF1.1 H,u 0.41 feet 12 in/ft 4.6 inches Use 5.0 inches of Agegate Base material ° Recommended Pavement Section 4O inches of asphalt concrete over 5.0 inches of Class 2 Aggregate Base material (based on • • • • the City of Carlsbad Standards for Design and Construction of Public Works Improvements) •: • • B-I __ 851855-013 APPENDIX B Asphalt Pavement Section Design Calculations (continued) 2) Avenida Del Alba between Station No 20+50 to 24+00 and Avenida La Cima between Station No 1+40to3+30 H = Thickness GE = Gravel Equivalent Design Traffic Index = 5.0 * Design Subgrade R-Value = 14 Class 2 Aggregate Base R-Value = 78 (based on Caltrans Standard Specifications Section 26) Asphalt Concrete (AC) Layer. GEac = (0.0032) (5.0) (100-78) + 020 = 0.55 feet Gfac = 2.54 Hac= 0.55 feet x 12 in/ft = 2.6 inches 2.55 Use 4.0 inches of asphalt concrete (City of Carlsbad minimum) Actual GE of asphalt concrete layer = (4/12 feet) 2.54 = 0.85 feet Aggregate Base (AB) Layer GE0 = (0.0032) (5.0) (100-14) = 1.38 feet GE*= 1.38 feet - 0.85 feet =0.53 feet GF,=1.1 HMj0.53 feet x12 in/ft =5.8inches 1.1 Use 6.0 inches of Aggregate Base material Recommended Pavement Section 4.0 inches of asphalt concrete over 6.0 inches of Class 2 Aggregate Base material (based on the City of Carlsbad Standards for Design and Construction of Public Works Improvements) B-2 __ Cello brativ noun Leighton and Associates 1961 - 2001 GEOTECHNICAL CONSULTANTS February 11, 2002 Project No. 851855-013 To: Continental Homes 2237 Faraday Avenue, Suite 100 Carlsbad, California 92008 Attention: . Mr. Dave JOnes Subject: Pavement Design Recommendations, Avenida Del Alba and a Portion of Avenida La Cima, Arroyo Vista Unit 3, Carlsbad Tract No. 90-03, Carlsbad, California References: Carlsbad, City of, 1996, Standards for Design and Construction of Public Works Improvements in the City of Carlsbad, California, Project No. 05332-12-0 1, dated April 20, 1993, revised December 10, 1996 Project Design Consultants, 2001, Plans for the Improvement of Shelley Property Unit No. 3, Carlsbad Tract No. 90-03, Carlsbad, California, Project No. CT 90-03, 8 Sheets,. dated March 29, 2001 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for Avenida Del Alba and a portion of Avenida La Cima (Station No. 17+00 to 18+13) within Unit No. 3 of the Arroyo Vista project (Carlsbad Tract No.90-03) located in Carlsbad, California. Two representative subgrade soil samples were obtained from along the streets. The samples were transported to our laboratory and R-value testing (in accordance with Caltrans Test Method 301) was performed. The test results indicated the subgrade soils have R-values ranging between 22 and 23. The approximate sample locations and results of the laboratory testing are presented in Appendix A. Based on the project Improvement Plans (Project Design Consultants, 2001), we understand that Avenida Del Alba and Avenida La Cima are considered local streets and have a traffic index (TI) of 5.0. According to the City requirements (Carlsbad, 1996), the minimum pavement section for streets having a TI of 5.0 or less (regardless of the R-value) is 4 inches of Asphalt Concrete (AC) over 4 inches of Aggregate Base (AB). 3934 Murphy Canyon Road, #B205, San Diego, CA 92123-4425 (858) 292-8030 • FAX (858) 292-0771 • www.leightongeo.com 81855-013 Pavement Section Utilizing Class 2 Aggregate Base Material Based on the above information, the recommended Class 2 aggregate base pavement section was calculated using the Caltrans Highway Design Manual Method and compared with the City of Carlsbad's minimum section thickness requirements. The recommended pavement section is presented on Table 1. The pavement section design calculations utilizing Caltrans design methods are presented as Appendix B. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Asphalt Concrete Class 2 Aggregate Traffic Design Thickness Base Thickness Location Index R-Value (in inches) (in inches) Avenida Del Alba and Avenida LaCima 5.0 22 4 5 (Station No. 17+00 to 18+13) Prior to placement of the Class 2 aggregate base material, the upper 12 inches of subgrade soils in the street (including beneath and a minimum of 6 inches beyond the back of the curb and gutter) should be scarified, moisture-conditioned to at least optimum moisture content and compacted to a minimum 95 percent relative compaction based on American Standard of Testing and Materials (ASTM) Test Method D1557. Class 2 Aggregate Base should then be placed a d compacted at a e..cnmon in accordance with ASTM Test Method D155 he aggregate base material should extend a minimum of 6 inches behind the back of the curb. ass ggrega e ase s ould conform to and be place in accor ance with the latest revision of the Cali mia Department of Transportation Standard Specifications (Section 26), the Greenbook specifications, and/ r the City of Carlsbad requirements. Asphalt Concrete should conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsb d requirements. If pavement is planned adjacent to landscaped areas, we recommend that appropriate measured be taken (such as keeping the amount of landsape irrigation to a minimum), installing area drains or other devices to reduce the possible adverse effects ofiwater on the pavement subgrade. .SLbLALO 1E -c Lsi L" -r741CJL 0 KJO 851855-013 If you have any questions regarding our report, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. • 0 Sean Co w rn Director of Engineering cc No. 54033 Exp 12/31/03 \'S• 0 auk Randall K. Wagner, EG 1612 Director of Geology Attachments: Appendix A - Laboratory Testing Procedures and Test Results • No. 1612 Appendix B - Asphalt Pavement Section Design Calculations * ENGEENG * p GEOLOGIST q Distribution: (6) Addressee °FCAt. (2) City of Carlsbad, Public Works Department 0 • Attention: Mr. Duane Soileu 851855-013 APPENDIX A Laboratory Testing Procedures and Test Results "R"-Value: The resistance "R"-value was determined by the California Materials Method No. 301 for subgrade soils. Three samples were prepared and exudation pressure and "R"-value determined on each one. The graphically determined "R"-value exudation pressure of 300 psi is summarized in the table below: Sample Number and Location Representative Location Sample Description R-Value Avenida La Cima R-10, Avenida La Cima (Station No. 17+00 to 18+13) Yellow-brown silty to Station No. 18±00 and Avenida Del Alba clayey SAND 23 .(Station No. 18±13to21±50) R-1 1, Avenida Del Alba - Station No. 25±00 Avenida Del Alba (Station No. 21+50 to 32±40). Olive-brown silty to clayey SAND 22 851855-013 APPENDIX B Asphalt Pavement Section Design Calculations 1) Avenida Del Alba and Avenida La Cimabetween Station No. 17+00 to 18+13 H = Thickness GE = Gravel Equivalent Design Traffic Index = 5.0 Design Subgrade R-Value = 22 Class 2 Aggregate Base R-Value = 78. (based on Caltrans Standard Specifications, Section 26) Asphalt Concrete (AC) Layer -. GEac = (0.0032) (5.0) (100-78) + 0.20 = 0.55 feet Gfac=2.54 Hac = 0.55 feet x 12 in/ft = 2.6 inches 2.55 Use 4.0 inches of asphalt concrete (City of Carlsbad minimum) Actual GE of asphalt concrete layer = (4/12 feet) 2.54 = 0.85 feet Aggregate Base (AB) Layer . GE0 = (0.0032) (5.0) (100-22) = 1.25 feet GE AB= 1.25 feet--0.85 = 0.4 feet GF=1.1 H0.4 feet x12 in/ft 4.4inches • - S Use 5.0 inches of Aggregate Base material S Recommended Pavement Section 4.0 inches of asphalt concrete over 5.0 inches of Class 2 Aggregate Base material (based on the City of Carlsbad Standards for Design and Construction of Public Works Improvements) b fati,1 - cp o C, sun 1961 - 2001 Leighton and Associates GEOTECHNICAL CONSULTANTS January 31, 2002 Project No. 851855-013 To: Continental Homes 2237 Faraday Avenue, Suite 100 Carlsbad, California 92008 Attention: Mr. Dave Jones Subject: Pavement Design Recommendations, RV Parking Facility, Lot 246, Arroyo Vista Unit 3, Carlsbad Tract No. 90-03, Carlsbad, California References: Carlsbad, City of, 1996, Standards for Design and Construction of Public Works Improvements in the City of Carlsbad, California, Project No. 05332-12-01, dated April 20, 1993, revised December 10, 1996 Project Design Consultants, 2002, Open Space Lots Construction Plans for Continental Homes Unit 3, Arroyo Vista, Carlsbad Tract No. 90-03, Carlsbad, California, Project No. CT 90-03, DrawingNo. 380- IN, Sheet 29 of 35, undated, received January 28, 2002 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for the RV Parking Facility on Lot 246 of Unit No. 3 of the Arroyo Vista project (Carlsbad Tract No.90-03) located in Carlsbad, California. One representative subgrade soil sample was obtained from Lot 246. The sample was transported to our laboratory and R-value testing (in accordance with Caltrans Test Method 301) was performed. The test result indicates the subgrade soils on the lot have aivR-value of 16 as presented in Appendix A. We have assumed that the RV Parking Facility will have a traffic index (TI) of 5.0. According to the City requirements (Carlsbad, 1996), the minimum pavement section for streets having a TI of 5.0, regardless of the R-Value, is 4 inches of Asphalt Concrete (AC) over 4 inches of Aggregate Base (AB). 3934 Murphy Canyon Road, #B205, San Diego, CA 92123-4425 (858) 292-8030 • FAX (858) 292-0771 9 www.leightongeo.com 851855-013 Pavement Section Utilizing Class 2 Aggregate Base Material Based on the above information, the recommended Class 2 aggregate base pavement section was calculated using the Caltrans Highway Design Manual Method and compared with the City of Carlsbad's minimum section thickness requirements. The recommended pavement section is presented on Table 1. The pavement section design calculations utilizing Caltrans design methods are presented as Appendix B. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base • Traffic Design Asphalt Concrete Class 2 Aggregate Location Index R-Value Thickness Base Thickness (in inches) (in inches) RV Parking Facility 5.0 16 4 6 Prior to placement of the Class 2 aggregate base material, the upper 12 inches of subgrade soils in the street (including beneath and a minimum of 6 inches beyond the back of the curb and gutter) should be scarified, moisture-conditionedto at least optimum moisture content and compacted to a minimum 95 percent relative compaction based on American Standard of Testing and Materials (ASTM) Test Method D1557. Class 2 Aggregate Base should then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material should be at least 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. Class 2 Aggregate Base should conform to and be placed in accordance with the latest revision of the California Department of Transportation Standard Specifications (Section 26), the Greenbook specifications, and/or the City of Carlsbad requirements. Asphalt Concrete should conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. Pavements Adjacent to Landscape Areas If pavement is planned adjacent to landscaped areas, we recommend that appropriate measured be taken (such as keeping the amount of landscape irrigation to a minimum), installing area drains or other devices to reduce the possible adverse effects of water on the pavement subgrade. -2- -' 851855-013 If you have any questions regarding our report, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. adLO4(- £No 45283"\ William D. Olson, RCE 45283((LU ( XP Senior Project Engineer 491 Randall K. Wagner, CEG 1612 Director of Geology J ED GE Attachments: Appendix A - Laboratory Testing Procedures and Test Results II * * Appendix B - Asphalt Pavement Section Design Calculations ENGINEERING GOLOGIST •. OF Distribution: (6) Addressee • • (2) City of Carlsbad, Public Works Department • Attention: Mr. Duane Soileu -3. 851855-013 APPENDIX A Laboratory Testing Procedures and Test Results "R"-Value: The resistance "R"-value was determined by the California Materials Method No. 301 for subgrade soils. Three samples were prepared and exudation pressure and "R"-value determined on each one. The graphically determined "R"-value exudation pressure-of 300 psi is summarized in the table below: SampleNumber I Representative on Sample Description R-Value R-1 RV Parking Area Medium brown clayey to 16 silty SAND 851855-013 APPENDIX B Asphalt Pavement Section Design Calculations 1) RV Parking Area H = Thickness GE = Gravel Equivalent Design Traffic Index = 5.0 Design Subgrade R-Value = 16 Class 2 Aggregate Base R-Value = 78, (based on Caltrahs Standard Specifications, Section 26) Asphalt Concrete (AC) Layer - GE. = (0.0032) (5.0) (100-78) + 0.20 = 0.55 feet 2.54 Hac = 0.55 feet x 12 inlft= 2.6 inches 2.55 Use 4.0 inches of asphalt concrete (City of Carlsbad minimum) Actual GE of asphalt concrete layer = (4/12 feet) 2.54 = 0.85 feet Aggregate'Base (AB) Layer GEtotal 135 feet GEAB 135 feet-0.850.5 feet GFAB =l.l 0.5-feetx12. in/ft =-534 inches •-------• - Use 6.0 inches of Aggregate Base material Recommended Pavement Section 4.0 inches of asphalt concrete over 6.0 inches of Class 2 Aggregate Base material (based on the City of Carlsbad Standards for Design and Construction of Public Works Improvements) In tj ' cp- AN__ Leighton and Associates 1961 - 2001 GEOTECHNICAL CONSULTANTS November 30, 2001 Project No. 85 1855-013 To: Continental Homes 2237 Faraday Avenue, Suite 100 Carlsbad, California 92008 Attfition: Mr. Dave Jones Subject Pavement Design Recommendations, Camino Alegre, Corte Del Cruce, and a Portion of Avenida La Cima, Arroyo Vista &Jnit 3, Carlsbad Tract No. 90-03, Carlsbad, California k References: Carlsbad, City of, 1996, Standards for Design and Construction of Public Works. Improvements in the City of Carlsbad, California, Project No. 05332-12-0 1, dated April 20, 1993, revised December 10, 1996 Leighton and Associates, .Inc.,O01, Pavement Design Recommendations, Arroyo Vista Unit 2, Carlsbad Tract No. 9003, Carlsbad, California, Project No. 851855-012, dated August 7, 2001, Revised August 16, 2001 Project Design Consultants, 2001, Plans for the Improvement of Shelley Property Unit No. 3, Carlsbad Tract No. 90-03; Carlsbad, California, Project No. CT 90-03, 8 Sheets, dated March 29, 2001 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for Camino Alegre, Corte Del Cruce, and a portion of Avenida La Cima (Station No. 3+50 to 17+00) within Unit No,, 3 of the Arroyo Vista project (Carlsbad Tract No.90-03) located in Carlsbad, California. Five representative subgrade soil samples were obtained from along the streets of the project. The samples were transported to our laboratory and R-value testing (in accordance with Caltrans Test Method 301) was performed. The test results indicated the subgrade soils have R-values ranging between less than 5 and 14. The approximate sample locations and results of the laboratory testing are presented in Appendix A. In accordance with City of Carlsbad requirements, the samples possessing an R- value of less than 12 require a pavement section utilizing a lime treated subgrade section (Carlsbad, 1996). 3934 Murphy Canyon Road, #B205, San Diego, CA 92123-4425 (858) 292-8030 • FAX (858) 292-0771 • www.leightongeo.com 851855-013 Based on the project Improvement Plans (Project Design Consultants, 2001), we understand that Camino Alegre, Corte Del Cruce, and Avenida La Cima are considered local streets and have a traffic index (TI) of 5.0. According to the City requirements (Carlsbad, 1996), the minimum pavement section for streets having a TI of 5.0 or less is 4 inches of Asphalt Concrete (AC) over 4 inches of Aggregate Base (AB). Pavement Section Utilizing Class 2 Aggregate Base Material Based on the above information, the recommended Class 2 aggregate base pavement section was calculated using the Caltrans Highway Design Manual Method and compared with the City of Carlsbad's minimum section thickness requirements. The recommended pavement section is presented on Table 1. The pavement section design calculations utilizing Caltrans design methods are presented as Appendix B. Table I Recommended Pavement Section Utilizing Class 2 Aggregate Base Asphalt Concrete Class 2 Aggregate Traffic Design Thickness Base Thickness Location Index R-Value (in inches) (in inches) Camino Alegre 5.0 14 4 6 F (Station No. 36+00 to 41+40) I Prior to placement of the Class 2 aggregate base material, the upper 12 inches of subgrade soils in the street (including beneath and a minimum of 6 inches beyond the back of the curb and gutter) should be scarified, moisture-conditioned to at least optimum moisture content and compacted to a minimum 95 percent relative compaction based on American Standard of Testing and Materials (ASTM) Test Method D1557. Class 2 Aggregate Base should then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test• Method D1557. The aggregate base material should be at least 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. Class 2 Aggregate Base should conform to and be placed in accordance with the latest revision of the California Department of Transportation Standard Specifications (Section 26), the Greenbook specifications, and/or the City of Carlsbad requirements. Asphalt Concrete should conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. Pavement Section Utilizing Lime-Treated Subgrade Soils Based on results for lime-treated subgrade soils in Unit 2 (Leighton, 2001), the representative subgrade soil sample having a R-Value of less than 12 (i.e. Sample No. 2b with R-value of 9) was retested for optimum lime content per American Standard of Testing and Materials (ASTM) Test Method C977. The optimum lime content was determined to be 5 percent quick lime. Testing of the lime treated sample resulted in an R- value of 69. The sulfate content testing (performed in accordance with Caltrans Test No. 417) of the lime- treated subgrade sample is provided in Appendix A. OJIOJJ-UL) Based on the above information, the recommended lime-treated pavement section was calculated using the Caltrans Highway Design Manual Method and compared with the City of Carlsbad's minimum section thickness requirements. The recommended pavement section is presented on Table 2. The pavement section design calculations utilizing Caltrans design methods are presented as Appendix B. Table 2 Recommended Pavement Section Utilizing Lime Treated Subgrade Soils Traffic Design AC Thickness Class 2 Base Lime Treated Location Index R-Value (in inches) Thickness Subgrade Layer (in inches) (in inches) Camino Alegre (Station 32+40 to 36+00), Avenida La 5.0 69 4 4 12 Cima (Station 3+50 to 17+00) and Corte De Cruce Prior to placement of the asphalt concrete and Class 2 Aggregate Base, the upper 12 inches of subgrade soils in the street (including beneath the curb and gutter) should be scarified, moisture-conditioned to at least optimum moisture content, and thoroughly mixed with 5 percent quick lime (or equivalent percentage of hydrated lime slurry). After setting for a minimum of 24 hours, the thoroughly mixed lime-treated subgrade soils should be compacted to a minimum 95 percent relative compaction based on ASTIvI Test Method Dl 557. After the minimum compaction is achieved for the lime-treated subgrade, the lime-treated subgrade soils should be allowed to cure. After the completion of the curing period, a minimum of 4 inches of Class 2 Aggregate Base should then be placed and compacted at a minimum 95 percent relative compaction in accordance with AS1'M Test Method D1557. The aggregate base material should be at least 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. After the placement and compaction of the Class 2 Aggregate Base, a minimum of 4 inches of asphalt concrete should be placed. Asphalt concrete and lime-treated subgrade soils should conform to and be placed in accordance with 1) the latest revision of the California Department of Transportation Standard Specifications; 2) in accordance with State of the Art Report 5, Lime Stabilization of the Transportation Research Board, National Research Council; 3) the "Greenbook" Standard Specifications for Public Works Construction (Sections 203 and/or 400); and/or 4) the City of Carlsbad requirements. Class 2 Aggregate Base should conform to and be placed in accordance with the latest revision of the California Department of Transportation Standard Specifications (Section 26), the Greenbook specifications, and/or the City of Carlsbad requirements. -3- JIM—: K. No. 16:12 rn CERTIFIED ENGINEERING / otOaIS/ 851855-013 Pavements Adjacent to Landscape Areas If pavement is planned adjacent to landscaped areas, we recommend that appropriate measured be taken (such as keeping the amount of landscape irrigation to a minimum), installing area drains or other devices to reduce the possible adverse effects of water on the pavement subgrade. If you have any questions regarding our report, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, ESS loly c/)Ij No. 45283 c_\:. d )ZL LEIGHTON AND ASSOCIATES, INC. A/IL 2 iL_i. William D. Olson, RCE 45283 Senior Project Engineer A~ - Randall K. Wagne CEIG 2612 Director of Geology Attachments: Appendix A - Laboratory Testing Procedures and Test Results Appendix B - Asphalt Pavement Section Design Calculations Distribution: (6) Addressee (2) City of Carlsbad, Public Works Department Attention: Mr. Duane Soileu 851855-013 APPENDIX A Laboratory Testing Procedures and Test Results "R"-Value: The resistance "R"-value was determined by the California Materials Method No. 30 1 f o r subgrade soils. Three samples were prepared and exudation pressure and "R"-value determined on each o n e . The graphically determined "R"-value exudation pressure of 300 psi is summarized in the table below: Sample Number and [ Representative Location Sample Description 1 R-Value j Location Camino Alegre Camino Alegre Olive-brown clayey Station No. 38+10 (Station No. 36+00 to 41+40) SAND 14 Camino Alegre Camino Alegre Pale Olive-brown sandy Station No. 34+00 (Station No. 32+40 to 36+00) CLAY Less than 5 Avenida La Cima Avenida La Cima Olive-brown sandy Station No. 7+60 (Station No. 3+50 to 10+50) CLAY Less than 5 Avenida La Cima Avenida La Cima Olive-brown sandy Station No. 12+20 (Station No. 10+50 to 17+00) CLAY 11 Corte Del Cruce Corte Del Cruce Olive-brown sandy Station No. 4+40 (Station No. 1+00 to 9+50) CLAY R-2b, Avenida de Sueno Avenida de Sueno and Calle sandy CLAY to clayey Station No. 47+25 Cordoba SAND with 5% quick 69 lime Soluble Sulfates: The soluble sulfate contents of selected samples were determined by Caltrans T e s t N o . 417. The test results are presented in the table below: Sample Location Sample Description Sulfate Content (%) Avenida de Sueno sandy CLAYto clayey SAND 0.18 -71 Maximum Density Tests: The maximum dry density and optimum moisture content of typical m a t e r i a l s were determined in accordance with ASTM Test Method D1557. The results of these tests are pre s e n t e d i n the table below: Sample Description Maximum Dry Optimum Moisture Density (pcO Content (%) sandy CLAY to clayey SAND with 5% quick lime 114.0 15.0 A-i 851855-013 APPENDiX B Asphalt Pavement Section Design Calculations 1) Camino Alegre (Station No. 36+00 to 41+40) Utilizing Aggregate Base Material H = Thickness GE = Gravel Equivalent Design Traffic Index = 5.0 Design Subgrade R-Value = 14 Class 2 Aggregate Base R-Value = 78. (based on Caltrans Standard Specifications, Section 26) Asphalt Concrete (AC) Layer GEac = (0.0032) (5.0) (100-78) + 0.20 = 0.55 feet Gfac = 2.54 Hac = 0.55 feet x 12 in/ft = 2.6 inches 2.55 Use 4.0 inches of asphalt concrete (City of Carlsbad minimum) Actual GE of asphalt concrete layer = (4/12 feet) 2.54 = 0.85 feet Aggregate Base (AB) Layer GEtotaj = (0.0032) (5.0) (100-14) = 1.38 feet GEAB = 1.38 feet -0.85 = 0.53 feet GFAB 1.1 HAB = 0.53 feet x 12 in/ft = 5.8 inches 1.1 Use 6.0 inches of Aggregate Base material Recommended Pavement Section 4.0 inches of asphalt concrete over 6.0 inches of Class 2 Aggregate Base material (based on the City of Carlsbad Standards for Design and Construction of Public Works Improvements) Ml 851855-013 APPENDIX B Asphalt Pavement Section Design Calculations (Continued) 2) Camino Alegre (Station No. 36+00 to 41+40). Avenida La Cima (Station No. 3+50 to 17+00), and Corte Del Cruce Utilizing Lime-Treated Subgrade Soils H = Thickness GE = Gravel Equivalent Design Traffic Index = 5.0 Design Subgrade R-Value = 69 Asphalt Concrete (AC) Layer GEac = (0.0032) (5.0) (100-78) + 0.20 = 0.55 feet Gfac = 2.54 Hac = 0.55 feet x 12 in/ft = 2.6 inches 2.55 Use 4.0. inches of asphalt concrete (City of Carlsbad minimum) Actual GE of asphalt concrete layer = (4/12 feet) 2.54 = 0.85 feet Aggregate Base (AB) Layer GE 0 = (0.0032) (5.0) (100-69) = 0.50 feet GE AB 0.50 feet - 0.85 = -0.35 feet GF= 1.1 HAB = -0.35 feet x 12 in/ft = -3.8 inches 1.1 Use 4.0 inches of Aggregate Base material (City of Carlsbad minimum) B-2 851855-013 APPENDIX B Asphalt Pavement Section Design Calculations (Continued) 2) Camino Alegre (Station No. 36+00 to 41+40), Avenida La Cima (Station No. 3+50 to 17+00). and Corte Del Cruce Utilizing Lime-Treated Subgrade Soils (continued) Lime Treated Subgrade Layer (assuming 5 % quick lime or equivalent percentage of hydrated lime slurry) GEtOthi = (0.0032) (5.0) (100-9) + 0.2 = 1.66 feet GE1 1.66 feet-0.850.81 feet GF1 = 0.9 + (400/1000) = 1.3 H1 = 0.81 feet 12 in/ft =7.5 inches 1.3 Use 12.0 inches of Lime Treated Subgrade (City of Carlsbad minimum) Recommended Pavement Section 4.0 inches of asphalt concrete over 4.0 inches of Class 2 Aggregate Base material over 12.0 inches of Lime Treated Subgrade (based on the City of Carlsbad Standards for Design and Construction of Public Works Improvements). ;c B-3