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HomeMy WebLinkAboutCT 00-06; BRESSI RANCH; 2004 PAVEMENT SECTION DESIGN RECOMMENDATIONS (VARIOUS DATES); 2004-11-17cr-00-0~ Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY December 7, 2004 Project No. 971009-011 To: Lennar Communities CITY OF CARLSBAD 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 APP AOVQ 0 WITH ADDITIONS Attention: Mr. John Slatton _LZ/2Z/Q1-___ 47M B Y Subject: Alternative Pavement Section Design Zlioni Street Including the Intersection with Poinsettia Lane and South of Poinsettia Lane, Station No. 56+75 to 65+35, Bressi Ranch, Carlsbad, California This letter presents our alternative preliminary pavement design recommendations for El Fuerte Street between Station No. 56+75 to 65+35 within the Bressi Ranch project, located in Carlsbad, California. Station No. 56+75 to 65+35 includes both the portion of El Fuerte south of Poinsettia Lane and the intersection with Poinsettia Lane. Based on the saturated subgrade soils conditions along the roathsay and our telephone conversations with Mr. Rick Wotipka of the City of Carlsbad, presented herein is our alternative preliminary pavement recommendations consisting of a stabilization fabric overlain by crushed rock, Class 2 aggregate base material, and asphalt concrete. Originally, two representative subgrade soil samples were obtained along the roadway alignment (Leighton, 2004a). 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 less than 5. The approximate sample locations and results of the laboratory testing are presented in Appendix A. Based on the project Improvement Plans (PDC, 2003), we understand that El Fuerte Street has a traffic index (TI) of 8.0. According to the City of Carlsbad requirements (Carlsbad, 1996), the minimum pavement section for streets having a TI of 8.0 is 4.0 inches of Asphalt Concrete (AC) over 6.0 inches of Aggregate Base (AB) regardless of the R-Value. Due to the presence of saturated subgrade soils along the roadway, the following alternative pavement section is recommended to reduce the impact of the saturated subgrade soils. The upper 24 inches of the entire roadway below the proposed finish grade surface (i.e. the top of the asphalt concrete) should be 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com K. (No. 1642 in * L CERTIFIED J * ENGINEERING GEOLOGIST 971009-011 removed. Areas where the subgrade soils are determined to be excessively wet below a depth of 24 inches should be removed and replaced with "dryer" soil, aggregate base material, crushed rock, or a combination of these materials. Once the removals are made, a woven geotextile stabilization fabric (Mirafi 600x or equivalent) should be placed across the entire roadway at a depth of 24 inches below the finish grade surface. Adjacent sections of the stabilization fabric should have a minimum overlap of at least 18 inches. Above the stabilization fabric, approximately 6 inches of 3/4-inch crushed rock should then be placed and densified in place to minimize void spaces within the rock. Subsequently, 12 inches of Caltrans Class 2 aggregate base material should then be placed and compacted in uniform lifts to a minimum 95 percent relative compaction (based on ASTM Test Method D1557) with a static roller. Vibratory compaction of the subgrade soils, crushed rock, or aggregate base material should not be performed. After the aggregate base material is placed and compacted, 6-inches of asphalt concrete should then be placed to complete the roadway. The Class 2 Aggregate Base shall 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 shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. (Ess!O (' No. 523 rM UJ Exp.L.ô CS Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. a-- William D. Olson, RCE 45283 Senior Project Engineer ~&' Randall K. Wagne , CEG 1612 Senior Associate Attachments: Appendix A - References Appendix B - Laboratory Testing Procedures and Test Results Distribution: (2) Addressee Lennar Communities, Attention: Mr. Jim Urbina City of Carlsbad, Public Works Department, Attention: Mr. Rick Wotipka (1) J. T. Kruer, Attention: Mr. Chuck Knight (1) Hazard Construction Company, Attention: Mr. Lino Cruz o -2- Leighton 971009-011 APPENDIX A 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. -, 2004, Pavement section Design Recommendations for El Fuerte Street South of Poinsettia Lane, Station 57+50 to Station 65+35, Bressi Ranch, Carlsbad, California, dated December 2, 2004. Leighton and Associates, 2004a, Pavement Section Design Recommendations for El Fuerte Street South of Poinsettia Lane, Station No. 57+50 to 65+35, Bressi Ranch, Carlsbad, California, Project No. 971009-011, dated November 10, 2004. -, 2004b, Geotechnical Recommendations Concerning Saturated and Yielding Street Subgrade Soils within a Portion of Poinsettia Lane and El Fuerte Street, Bressi Ranch, Carlsbad, California, Project No. 971009-011, dated November 29, 2004. Project Design Consultants (PDC), 2003, Plans for the Improvement of El Fuerte Street, Carlsbad, California, Project No. CT-00-06, Drawing No. 400-8E, 23 Sheets, dated February 21, 2003 (revised July 15, 2003). A-i Leighton 971009-011 APPENDIX B "W-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 Sample Location [ Sample Description [_R-Value R-131 El Fuerte Street, Station No. 59+50 Olive brown lean CLAY 5 with sand R-132 El Fuerte Street, Station No. 61+50 Olive-brown lean CLAY 5 R-13 1A El Fuerte Street, Station No. 59+50 Olive-brown lean CLAY 49 with 5 percent lime R-132A El Fuerte Street, Station No. 61+50 Olive-brown lean CLAY78 with 5 percent lime B-i Leighton CITY OF CARLSBAD Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY / APPROVED ' WITH ADDITIONS 1Z52W262,zf BY DATE DATE October 25, 2004 Project No. 971009-027 To: Lennar Communities 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention: Mr. John Slatton Subject: Pavement Section Design Recommendations for the Community Park Parking Area, Planning Area OS-2, Bressi Ranch, 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 Gillespie Design Group, 2004, Bressi Ranch Landscape and Construction Plans for Open Space Area 2, CT 02-14/PUD 02-06, Carlsbad, California, Sheets 1 through 16 of 37, Job No. 02-116, dated December 4, 2003, 2nd Plan Check dated September 10, 2004 Project Design Consultants, 2004, Precise Grading Plans: Bressi Ranch Parks, PA-9, PA-10, PA-12, and OS-2, Carlsbad Tract No. 02-14, 7 Sheets, dated September 9, 2004 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for the Community Park parking area within Planning Area OS-2 of the Bressi Ranch project located in Carlsbad, California. One representative subgrade soil sample was obtained within the proposed parking area. 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 have an R-value of 7. The approximate sample location and result of the laboratory testing is presented in Appendix A. It should be noted that for subgrade samples with 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 9711090-027 an R-value less that is less than 12, the City of Carlsbad requires further testing and an engineering evaluation for the possible implementation of a lime treated subgrade pavement section. Based on the project Improvement Plans (Project Design Consultants, 2004), we have assumed that the Community Park parking area has 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 is 4.0 inches of Asphalt Concrete (AC) over 4.0 inches of Aggregate Base (AB) regardless of the R- Value. The minimum lime-treated subgrade soil thickness is 8 inches regardless of the R-Value. In summary, the following sections address the City's requirements and present the recommended or preferred pavement design sections. Pavement Section Utilizing Class 2 Aggregate Base Material Based on the above information, a Class 2 Aggregate Base material pavement section was calculated using the Caltrans Highway Design Manual Method and compared with the City of Carlsbad's minimum section thickness requirements. The calculated pavement section is presented on Table 1. I dult I. Recommended Pavement Section Utilizing Class 2 Aggregate Base Asphalt Concrete Class 2 Location Traffic Design Thickness Aggregate Base Index R-Value (inches) Thickness (inches) Community Park Parking Area 5.0 7 J 4.0 [ 8.0 Prior to placement of the aggregate base material, the upper 12 inches of subgrade soils (including beneath the curb and gutter and 6-inches behind the curb and gutter) shall be scarified, moisture- conditioned (or dried back) as necessary 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 shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall conform to and be placed in accordance with the latest revision of the California Department of Transportation Standard Specifications (Section 4 Leighton 9711090-027 26), the Greenbook specifications, and/or the City of Carlsbad requirements. Asphalt Concrete shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. Concrete Pavement Section Our review of the Community Park Landscape and Construction Plans (Gillespie, 2004) indicates that a portion of the parking area will consist of colored stamped concrete. Based on the anticipated traffic loads, we recommend that the concrete pavement design consist of a minimum of 6 inches of Portland Cement Concrete (PCC) with reinforcement rebars over 6 inches of Class 2 aggregate base material. The reinforcement should consist of No. 4 rebars placed at mid-height in the concrete slab at 18 inches on center (each way) at a minimum. The uld have a minimum modulus of rupture of at least 600 psi and a minimum strength f , @soiPs si. Prior to placement of the aggregate base material, the upper 12 inches of subgra e (including beneath the curb and gutter and 6-inches behind the curb and gutter) shall be scarified, moisture- conditioned (or dried back) as necessary to at least optimum moisture content and compacted to a minimum 95 percent relative compaction based on ASTM Test Method Dl 557. Soluble sulfate content testing of representative soils within the community park and the parking area indicates the soils possess a severe soluble sulfate content (per Uniform Building Code Table 19-A-4). As a result, the concrete pavement section (and other concrete improvements in contact with the on-site soils) should be designed for a severe soluble sulfate content. Pavement Section Utilizing Lime-Treated Subgrade Soils The following pavement section utilizes a lime-treated subgrade in accordance with the City of Carlsbad requirements. The R-Value was retested for optimum lime content (per American Standard of Testing and Materials [ASTM] Test Method C977) and soluble sulfate content (in accordance with Caltrans Test No. 417). The optimum lime content was determined to be 5-percent quick lime while the soluble sulfate content was found to be 0.2 percent. After the lime was added to the sample and the sample allowed to cure a minimum of 24 hours, testing of the lime treated sample resulted in a minimum R-value of 49. Based on the proposed street information, the 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 lime-treated subgrade pavement section is presented on Table 2. 4 -3- Leighton 9711090-027 Table 2 Pavement Section Utilizing Lime Treated Subgrade Soils Traffic Design AC Class 2 Base Lime Treated Location Index R-Value Thickness Thickness Subgrade Layer (inches) (inches) (inches) F community Park Parking Area 5.0 49 4.0 4.0 ] 8.0 Prior to placement of the asphalt concrete and Class 2 Aggregate Base, the upper 8 inches of the subgrade soils (including beneath the curb and gutter and 6-inches behind the curb and gutter) shall 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 shall be compacted to a minimum 95 percent relative compaction based on ASTM Test Method D1557. After the lime- treated subgrade soils are compacted, a curing compound should be applied to the surface of the lime-treated subgrade soils and the materials allowed to cure. After the completion of the curing period, a minimum of 4 inches of Class 2 Aggregate Base shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 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 aggregate base material, a minimum of 4-inches of asphalt concrete shall be placed. Asphalt Concrete, Aggregate Base, and lime-treated subgrade soils shall 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. Recommended Pavement Section Based on our experience with similar soils in the vicinity of the site, we recommend that the pavement section for the Community Park parking area utilize the Class 2 Aggregate Base Material design with no lime treatment of the subgrade soils, as discussed abojIn summary,j we 7 avThiiid that the fTãiie y thin layers lime treatment subgrade sis, consisting of lean silty c and sandy clays, are very sensitive to moisture changes injhe soil, and ultimt ysuseptibl potentiiLvminor cracking during the curjgocjTherefore, it is our opinion that utilizing the Class 2 Aggregate Base Material pavement design, as presented Table 1, will result in a better Oiu DekSWA44 The 110, Leighton 9711090-027 performing pavement section. In addition, if pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, C0 LEIGHTON AND ASSOCIATES, INC. : William D. Olson, RCE 45283 Senior Project Engineer Randall K. Wagner CEG 1612 Senior Associate 4 o.1612\ II * L CERTIFIED * ENGINEERING I Attachments: Appendix A - Laboratory Testing Procedures and Test Results GEOLOGIST OF MO Distribution: (2) Addressee (1) Lennar Communities, Attention: Mr. Jim Urbina Lennar Communities, Attention: Ms. Peggy Ashby City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt -5- Leigh ton 971009-027 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. The 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 Sample Location Sample Description R-Value R-135 Community Park Parking Area Yellow brown CLAY 7 R-135A Community Park Parking Area Yellow brown CLAY49 with 5-percent lime A-i Leighton :• Pavement Section Design Recommendations for Community Parking areas, Planning Area OS-2. Recommended Pavement Sections Asphalt Class 2 .1 Location Aggregate Index Traffic R-Value Concrete Base Thickness I Thickness I Community Parking 5.0 7 4.0 8.0 Area OS-2 CITY STANDARD . MINIMUMS PER . 7. . 4.0 8.O QS-17 The recommendations, by Leighton & Associates, for Community Parking areas, Planning Area OS-2. The recommended section meet the minimum structural section as described in the City design standards GS-17. ME CITY CARLSBTD Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY E!?BQ\ 1 TH ADDmoNs _gffj - BY DATE October 14, 2004 Project No. 971009-023 To: Lennar Communities 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention: Mr. John Slatton Subject: Pavement Section Design Recommendations for Keeneland Drive Station No. 0+60 to 8+40 (North of Muirfields Drive) and Allston Street Station No. 0+50 to 8+50, Planning Area PA-1 1, Bressi Ranch, 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 (PDC), 2004, Plans for the Improvement of Bressi Ranch, Planning Area 11, Carlsbad, California, Drawing No. 418-8, ii Sheets, dated June 30, 2004 In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for Keeneland Drive (between Station No. 0+60 to 8+40) and Allston Street (Station No. 0+50 to 8+50) north of Muirfields Drive in Carlsbad, California. Four representative subgrade soil samples were obtained along the roadway alignments. 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 from 15 to 30. The approximate sample locations and results of the laboratory testing are presented in Appendix A. Based on the project Improvement Plans (Project Design Consultants, 2004), we understand that Keeneland Drive and Allston Street have a Traffic Index (11) of 6.0. According to the city 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 971009-023 requirements (Carlsbad, 1996), the minimum pavement section for streets having a TI of 6.0 is 4 inches of Asphalt Concrete (AC) over 6 inches of Aggregate Base (AB) regardless of the R- Value. 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 sections are presented on Table 1. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Class lass 2 Location Traffic Design Concrete Aggregate Base Index R-Value Thickness Thickness (inches) (inches) Keeneland Drive (Station No. 0+60 to 3+00) and Allston Street (Station No. 0+50 to 4+00) 6.0 15 4.0 12.0 Keeneland Drive (Station No. 3+00 to 8+40) 6.0 22 4.0 10.0 Allston Street (Station No. 4+00 to 8+50) 6.0 30 4.0 8.0 Prior to placement of the street aggregate base material, the upper 12 inches of subgrade soils in the street (including beneath the curb and gutter and 6-inches behind the curb and gutter) shall be scarified, moisture-conditioned (or dried back) as necessary 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 shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall 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 shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. 4 - 2 - Leighton 9711090-023 If pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, 41 D. LEIGHTON AND ASSOCIATES, INC. rn CY- William D. Olson, RCE 45283 Senior Project Engineer Attachments: Appendix A - Laboratory Testing Procedures and Test Results Distribution: (2) Addressee Lennar Communities, Attention: Mr. Jim Urbina City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt (1) J. T. Kruer, Attention: Chuck Knight -3- Leighton 971009-023 APPENDIX A "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 Sample Location Sample Description 1_R-Value R-137 Keeneland Drive, Station No. 4+75 Yellow-brown sandy lean 22 CLAY R-138 Keeneland Drive, Station No. 2+55 Yellow-brown lean 15 CLAY R-139 Allston Street, Station No. 2+75 Yellow-brown lean 15 CLAY R-140 Allston Street, Station No. 7+00 Yellow-brown sandy lean CLAY 30 A-i Leighton Pavement Section Design Recommendations for Keeneland Dr. Sta. (0+60 to 8+40), North of. Muirfields, and Allston Street Sta. (0+50 to 8+50) in PA-11. Recommended Pavement Sections Asphalt Class 2 I Location Aggregate Base Traffic R-Value Concrete Index Thickness I Thickness I Keeneland (0+60 to 3+00), and Allston (0+50 to 6.0 15 4.0 12.0 CITY DESIGN STANDARD 60 15 12.0 4 MINIMUMS PER GS-17 Keeneland, 6.0 22 3+00 to 8+40 4.0 1 10.0 - 'CITYDESIGN .. . STAND,tfl.JJ A T)U' 4 •.) •, 4 MINIMUMS PER 6.0 10.0 . U GS-17 Allston, I 6.0 30 4.0 8.0 4+00to8+50 I CITY DESIGN- S . TANj)A" . . MINIMUMS PER . 4.0 8.0 . GS-17 The recommendations, by Leighton & Associates, for Keeneland Dr. Sta. (0+60 to 8+40), North of Muirfields, and Allston Street Sta. (0+50 to 8+50) in PA- 11. The recommended sections meet the minimum structural section as described in the City design standards GS-17. CITY OF CARLSBAD Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY APPROVED O WITH ADDITIONS BY DATE ,?2Y2VAAE- Y/.o0+ September 27, 2004 Project No. 971009-023 To: Lennar Communities 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention: Mr. John Slatton Subject: Pavement Section Design Recommendations for the Utility Access Road, Between Lots 4 and 5 and South of Keeneland Drive, Planning Area PA- 11, Bressi Ranch, 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 (PDC), 2004, Plans for the Improvement of Bressi Ranch, Planning Area ii, Carlsbad, California, Drawing No. 418-8, 11 Sheets, dated June 30, 2004 In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for the Utility Access Road located between Lots 4 and 5 and south of Keeneland Drive within Planning Area PA- 11 of the Bressi Ranch project located in Carlsbad, California. One representative sample for both Keeneland Drive and the Utility Access Road was obtained. The sample was transported to our laboratory and R-value testing (in accordance with Caltrans Test Method 301) was performed. The test result indicated the subgrade soils have an R- value of 17. The approximate sample location and result of the laboratory testing is presented in Appendix A. 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 9711090-029 Based on the project Improvement Plans (Project Design Consultants, 2004), we have assumed that the Utility Access Road has 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 is 4 inches of Asphalt Concrete (AC) over 4 inches of Aggregate Base (AB) regardless of the R-Value. 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 sections are presented on Table 1. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Traffic Design Asphalt Concrete Class 2 Aggregate Base Location Index R-Value Thickness Thickness ____ (in inches) __________________ (in inches) Utility Access Road 5.0 17 4.0 6.0 Prior to placement of the aggregate base material, the upper 12 inches of subgrade soils (including 6 inches behind the curb and gutter) shall be scarified, moisture-conditioned (or dried back) as necessary 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 shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall 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 shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. -2- Leighton 9711090-023 If pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. gtRandall K. G1612 Senior Associate Attachments: Appendix A - Laboratory Testing Procedures and Test Results Distribution: (2) Addressee (2) City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt (2) Lennar Communities, Attention: Mr. Noah Lashbrook Leighton 971009-023 APPENDIX A "R"-Value: The resistance "Re-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 Sample Location Sample Description 1_R-Value R-133 Keeneland Drive, Station J Yellow brown Clayey SD 17 No. 4+30 11 A-i Leighton Pavement Section Design Recommendations for Utility Access Road, Between lots 4 and5 and South of:Keeneland Dr. in Pa-11. Recommended Pavement Sections Class 2 Traffic Aggregate Location R-Value Concrete Index Base Thi ckness Thickness Utility Access Road 5.0 17 4.0 6.0 CITY DESIGN V V STANDARD MINIMUMS PER °i 4.0 V 6.0 CS -17 V V V ____________ The recommendations, by Leighton & Associates, for Utility Access Road, Between lots 4 and 5 and South of Keeneland Dr. in Pa-1 1. The recommended section meet the minimum structural section as described in the City design standards GS- 17. V I CITY OF CARLSBAD Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY APPROVED ADDITIONS A;2 9/3oi'o4 DATE September 23, 2004 Project No. 971009-025 To: Greystone Homes 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention: Mr. Keith Randhahn Subject: Pavement Section Design Recommendations for Private Driveway 'EE' and Associated Parking Areas Between Buildings No. 1 and 2, a Portion of Cottage Drive and Dartington Way, Affordable Housing Site, Planning Area PA- 15, Bressi Ranch, 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 (PDC), 2004, Bressi Ranch Affordable Housing Improvement Plans, CT 03-03, Carlsbad, California, Drawing No. 415-3, 8 Sheets, dated April 12, 2004 In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for Private Driveway 'EE' and the associated parking areas between Buildings 1 and 2 and a portion of Cottage Drive (Station No. 1+30 to 3+90) and Dartington Way (Station No. 1+30 to 4+00) for the Affordable Housing Site within Planning Area PA-15 of the Bressi Ranch project located in Carlsbad, California. Three representative subgrade soil samples were obtained along the subject private driveway alignments. 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 from 24 to 29. The approximate sample locations and results of the laboratory testing are presented in Appendix A. 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com Based on the project Improvement Plans (Project Design Consultants, 2004), we have assumed that Private Driveway 'EE', the associated parking areas, and a portion of Cottage Drive and Dartington Way 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 is 4 inches of Asphalt Concrete (AC) over 4 inches of Aggregate Base (AB) regardless of the R-Value. 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 sections are presented on Table 1. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Location Traffic Design Asphalt Concrete Thickness Class 2 Aggregate Base Index R-Value (in inches) Thickness (in inches) Private Driveway 'EE', associated parking areas, Cottage Drive (Station No. 1+30 to 3+90) 5.0 24 4.0 4.0 and Dartington Way (Station No. 1+30 to 4+00) Prior to placement of the aggregate base material, the upper 12 inches of subgrade soils (including 6 inches behind the curb and gutter) shall be scarified, moisture-conditioned (or dried back) as necessary 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 shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall 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 shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. -2- Leighton 971009-025 If pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. Mwc---~- Randall K. Wagner, CEG 1612 Senior Associate Attachments: Appendix A - Laboratory Testing Procedures and Test Results Distribution: (4) Addressee (2) City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt -3- Leighton 971009-025 APPENDIX A "R"-Valiie: 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 Sample Location Sample Description R-Value R-128 Dartington Way, Station Yellow brown silty SAND 26 No. 2+25 R-129 Cottage Drive, Station No. Yellow brown silty SAND 29 3+50 R-130 Private Driveway 'EE' Yellow brown silty SAND 2A- A-1 Leighton Pavement Section Design Recommendations for Private Driveway 'EE' and Associated Parking Areas Between Bldgs 1 and 2, a portion of Cottage Dr. and Dartington Way, Affordable Housing Site, in PA-15. Recommended Pavement Sections Location Traffic Index R-Value Asphalt Concrete Thi ckness Class 2 Aggregate Base Thickness Private Driveway 'BE', associated parking areas, Cottage Dr. (Sta. 5.0 24 4.0 4.0 1+30 to 3+90) and Dartington Way (Sta. 1+30t04+00) CIT\ DESU.;N . SI.\Nl).Rl) Sll\I1LIs PER S ) 241 . 4 0 4 I) The recommendations, by Leighton & Associates, for Private Driveway 'EE' and Associated Parking Areas Between Bldgs 1 and 2, a portion of Cottage Dr. and Dartington Way, Affordable Housing Site, in PA-is. The recommended section meet the minimum structural section as described in the City design standards GS-17. CITY OF Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY 9 WITH ADDITIONS F, M— September 15, 2004 No. 971009-023 To: Lennar Communities 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention: Mr. John Slatton Subject: Pavement Section Design Recommendations for Muirfields Drive, Station No. 0+60 to 7+26, Planning Area PA- 11, Bressi Ranch, 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 (PDC), 2004, Plans for the Improvement of Bressi Ranch, Planning Area 11, Carlsbad, California, Drawing No. 418-8, 11 Sheets, dated June 30, 2004 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for Muirfields Drive (between Station No. 0+60 and 7+26), in Carlsbad, California. Two representative subgrade soil samples were obtained along the roadway alignment. 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 from 19 to 32. The approximate sample locations and results of the laboratory testing are presented in Appendix A. Based on the project Improvement Plans (Project Design Consultants, 2004), we understand that Muirfields Drive have a Traffic Index (TI) of 6.0. According to the city requirements (Carlsbad, 3934 Murphy Canyon Road, Suite B205.San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 9711090-023 1996), the minimum pavement section for streets having a TI of 6.0 is 4 inches of Asphalt Concrete (AC) over 6 inches of Aggregate Base (AB) regardless of the R-Value. 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 sections are presented on Table L Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Class 2 Asphalt Concrete Traffic Design Aggregate Base Location Index R-Value Thickness Thickness (inches) (inches) Muirfields Drive, 6.0 32 4.0 7.0 Station No. 0+60 to 5+00 Muirfields Drive, Station No. 5+00 to 7+26 6.0 19 4.0 11.0 Prior to placement of the street aggregate base material, the upper 12 inches of subgrade soils in the Street (including beneath the curb and gutter and 6-inches behind the curb and gutter) shall be scarified, moisture-conditioned (or dried back) as necessary 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 shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall 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 shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. 4 -2- Leighton 9711090-023 If pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. SSi 4l' cf No. 45283 :t EXP CIVI 4/ Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. 14 / ".. mt - William D. Olson, RCE 45283 Senior Project Engineer K. (I No. 1612%\ 11* (X CER11FIED J * Randall K. Wagner, 7CG \ €NGNEERIN / Senior Associate IPA GOGIST) Attachments: Appendix A - Laboratory Testing Procedures and Test Results Distribution: (2) Addressee Leimar Communities, Attention: Mr. Jim Urbina City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt (1) J. T. Kruer, Attention: Chuck Knight -3- Leighton 971009-023 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 Sample Location Sample Description R-Value R-126 Muirfields Drive, Station No. 1+25 Light Brown silty SAND 32 R-127 Muirfields Drive, Station No. 6+00 Light brown clayey SAND 19 j A-i Leighton Pavement Section Design Recommendations for Muirfields Dr (STA 0+60 to 7+26) in PA-11. Recommended Pavement Sections Asphalt Class 2 Location Traffic R-Value Concrete Aggregate Index Thickness Base Thickness Muirfields, 0+60 to 5+00 6.0 32 4 7 0 CITY DESIGN STANDARD MINIMUMS PER 60 40 GS-17- Muirfields, 5+00to7+26 6.0 19 4 11.0 CITY DESIGN STANDARD MINIMUMS PER 19 4 0 11 0 GS-17 The recommendations, by Leighton & Associates, for Muirfields Dr (STA 0+60 to 7+26) in PA- 11. The recommended sections meet the minimum structural section as described in the City design standards GS-17. CITY OF Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY APPRQVED M WITH ADDITIONS In 01 9199IC4- September 15, 2004 Project No. 971009-009 To: Lennar Communities 525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention: Mr. John Slatton Subject: Pavement Section Design Recommendations for the North and South Sides of Poinsettia Lane West of El Fuerte Street, Station No. 68+55 to 79+50, Bressi Ranch, Carlsbad, California References: Carlsbad, City of, 1996, Standards for Design and Construction of Public Works Improvements in the City of Carlsbad, California, Project No. 0533212-01, dated April 20, 1993, revised December 10, 1996 Kimley-Horn, 2003, Improvement Plans for Poinsettia Lane at Bressi Ranch, Project No. CT99-03, Drawing No. 397-2K, 36 Sheets, dated February 12, 2003 Introduction This letter presents our preliminary pavement design recommendations for the north and south sides of Poinsettia Lane west of El Fuerte Street (between Station No. 68+55 and 79+50) within the Bressi Ranch project, located in Carlsbad, California. Four representative subgrade soil samples were obtained along the roadway alignment. 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 from 18 to 21. The approximate sample locations and results of the laboratory testing are presented in Appendix A. Based on the project Improvement Plans (Kimley-Horn, 2003), we understand that Poinsettia Lane has a traffic index (TI) of 8.5. According to the City of Carlsbad requirements (Carlsbad, 1996), the minimum pavement section for Lanes having a TI of 8.5 is 5.0 inches of Asphalt Concrete (AC) over 6.0 inches of Aggregate Base (AB) regardless of the R-Value. 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 971009-009 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. Note that the recommended asphalt thickness of 5.5 inches, which is greater than the minimum thickness required by City, is based on the results of the Caltrans Highway Design Manual Method calculation. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Asphalt Class 2 Traffic Design Concrete Aggregate Base Location Index R.-Value Thickness Thickness (inches) (inches) Poinsettia Lane, Station No. 8.5 18 5.5 16.0 68+55 to 79+50 Prior to placement of the Lane aggregate base material, the upper 12 inches of subgrade soils in the Lane (including 6-inches behind the curb and gutter) shall be scarified, moisture-conditioned (or dried back) as necessary 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 shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall 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 shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. If pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. -2- Leighton 971009-009 If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, -\ LEIGHTON AND ASSOCIATES, INC. 283 01 4- clo, William D. Olson, RCE 45283 Senior Project Engineer Aana I if Senior Associate K. Wagner,CEGG1 No. 1612 CERTIFIED ENGINEERING / GEOLOGIST Attachments: Appendix A - Laboratory Testing Procedures and Test Results Distribution: (2) Addressee Lennar Communities, Attention: Mr. Jim Urbina City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt (1) J. T. Kruer, Attention: Mr. Chuck Knight (1) Hazard Construction Company, Attention: Mr. Lino Cruz -3- Leighton 971009-009 APPENDIX A Laboratory Testing Procedures and Test Results 'R"-Value: The resistance "W'-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 1 Sample Location Sample Description R-Value R-122 Poinsettia Lane, Station Pale olive brown clayey 19 No. 70+50 (South Side) SAND R-123 Poinsettia Lane, Station Pale olive brown clayey 21 No. 76+00 (South Side) SAND R-124 Poinsettia Lane, Station Pale olive brown clayey 18 No. 77+50 (North Side) SAND R-I25 Poinsettia Lane, Station Pale olive brown clayey 18 No. 71+50 (North Side) SAND A-i Leighton Pavement Section Design Recommendations for Poinsettia Rd., Station No. 68+55 to 79+50. Recommended Pavement Sections Class 2 Traffic Aggregate Location R-Value Concrete Index Base Thickness Thickness Poinsettia Rd, 68+55to79+50 8.5 18 5.5 16.0 ITYDF;.SICN S1.iJD:RI) ii I \IS \1 L - I 5.() I ilJ The recommendations, by Leighton & Associates, for Poinsettia Rd. 68+55 to 79+50. The recommended section exceeds the minimum structural section as described in the City design standards GS-17. Leighton & Assoc. increased the asphalt, thickness in order to meet the higher standard thickness as described in the CalTrans Highway Design Manual. CITY OF CARLSBAD Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY APEROVED U WITH ADDITIONS I September 9, 2004 Project No. 971009-029 To: Greystone Homes 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention: Mr. Keith Randhahn Subject: Pavement Section Design Recommendations for Alleys 'BB', 'JJ', 'KK', 'LL', '00', and '5', Planning Areas PA-7 and PA-8, Bressi Ranch, 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 (PDC), 2004a, Plans for the Improvement of Bressi Ranch Planning Area 7, Carlsbad, California, Drawing No. 411-4, 13 Sheets, dated April 22, 2004 Project Design Consultants (PDC), 2004b, Plans for the improvement of Bressi Ranch Planning Area 8, Carlsbad, California, Drawing No. 413-8, 16 Sheets, dated April 22, 2004 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for Alleys 'BB', 'JJ', 'KK', 'LL', '00', and 'S' within Planning Areas PA-7 and PA-8 of the Bressi Ranch project located in Carlsbad, California. Eight representative subgrade soil samples were obtained along the alley alignments. 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 from 15 to 54. The approximate sample locations and results of the laboratory testing are presented in Appendix A. 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 9711090-029 Based on the project Improvement Plans (Project Design Consultants, 2004a and 2004b), we understand that Alleys 'BB', 'JJ', 'KK', 'LL', '00', and 'S' 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 is 4 inches of Asphalt Concrete (AC) over 4 inches of Aggregate Base (AB) regardless of the R-Value. 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 sections are presented on Table 1. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Asphalt Concrete Class 2 Location Traffic Design Thickness Aggregate Base Index R-Value (in inches) Thickness (in inches) Alleys 'BB', and '00' 5.0 15 4.0 6.0 Alleys 'JJ', 'KK', 'LL', and 'S' 5.0 25 4.0 4.0 Prior to placement of the street aggregate base material, the upper 12 inches of subgrade soils in the street (including 6 inches behind the curb and gutter) shall be scarified, moisture-conditioned (or dried back) as necessary 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 shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall 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 shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. 4 -2- Leighton 9711090-029 If pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, 0. Ô%LEIGHTON AND ASSOCIATES, INC. No. 45293 ft)) ISjj William D Olson, RCE 45283 N...SOi- C-"' Senior Project Engineer r No. 1612 M CERTIFIED ENGINEERING Randall K. Wagner, C 1612 P>,GEOLOGIS. Senior Associate OF CA0 Attachments: Appendix A - Laboratory Testing Procedures and Test Results Distribution: (4) Addressee (2) City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt Leighton 971009-029 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 Sample Location Sample Description R-Valuel R-107 Alley 'KK', Station No. Yellow brown silty SAND 38 3+50 R-108 Alley 'LL', Station No. Light brown silty SAND 54 5+00 R-109 Alley 'LL', Station No. Light brown silty SAND 47 1+90 R-113 Alley 'BB', Station No. Olive brown silty sandy CLAY 15 3+25 R-1 14 Alley '00', Station No. Yellow brown silty clayey SAND 17 6+00 R-1 15 Alley' '00', Station No. Olive brown silty sandy CLAY 23 2+50 R-120 Alley, '5', Station No. Yellow brown silty SAND 43 2+35 R-121 Alley 'JJ', Station No. _3+25 Yellow brown silty SAND 44 A-i Leighton CITY OF CARLSBAD Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY APPROVED WITH ADDITIONS BY DATE July 27, 2004 40 Project o. 971009-020 To: Lennar Communities 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention: Ms. Kristine Zortman Subject: Pavement Section Design Recommendations for Edendale Street, Heritage Drive, and a Portion of Peppertree Way, Muirfields Drive, Huntington Drive, and Astoria Street, Planning Area PA-8, Bressi Ranch, 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 (PDC), 2004, Plans for the Improvement of Bressi Ranch Planning Area 8, Carlsbad, California, Drawing No. 413-8, 16 Sheets, dated April, 22, 2004 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for Edendale Street, Heritage Drive, and a portion of Peppertree Way (between Station No. 1+10 and 6+20), Muirfields Drive (between Station No. 7+26 and 9+70), Huntington Drive (between Station No. 1+25 and 6+50), and Astoria Street (between Station No. 8+50 and 10+50) of Bressi Ranch Planning Area PA-8, located in Carlsbad, California. Nine representative subgrade soil samples were obtained along the roadway alignments. The samples were transported to our laboratory and R-value testing (in accordance with Caltrans Test Method 301) was have R-values.ranging from .13 to The approximate sample locations and resii1i3f the laboratory testing are presented in Appendix A. 3934 Murphy Canyon Road, Suite 6205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 9711090-020 Based on the project Improvement Plans (Project Design Consultants, 2004), we understand that all) ..PA8 have- a-Traffic -Index- (P1)- of-60 According to the city requirements (Carlsbad, 1996), the minimum pavement section for streets having a TI of 6.0 is 4 inches of Asphalt Concrete (AC) over 6 inches of Aggregate Base (AB) regardless of the R- Value. Pavement Section Utilizing Class 2 Aggregate Base Material Based on the above information, the recommended Class 2 Aggregate Base pavement sections were calculated using the Caltrans Highway Design Manual Method and compared with the City of Carlsbad's minimum section thickness requirements. The recommended pavement sections are presented on Table 1. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Asphalt Concrete Class 2 Location Traffic Design Thickness Aggregate Base Index R-Value (inches) Thickness (inches) Edendale Street, 6.0 15 4.0 12.0 Station No. 1+50 to 11+50 Heritage Drive, 6.0 31 4.0 8.0 Station No. 4+00 to 12+70 Peppertree Way, 6.0 13 4.0 12.0 Station No. 1+10 to 6+20 Muirfields Drive, 6.0 38 4.0 6.0 Station No.7+26 to 9+70 Huntington Drive, 6.0 18 4.0 11.0 Station No. 1+25 to 6+50 Astoria Street, 6.0 24 4.0 9.0 Station No. 8+50 to 10+50 Prior to placement of the street aggregate base material, the upper 12 inches of subgrade soils in the street (including beneath the curb and gutter) shall be scarified, moisture-conditioned (or dried back) as necessary to at least optimum moisture content and compacted to a minimum 95 percent 4 -2- Leighton / / I / / 'I 9711090-020 relative compaction based on American Standard of Testing and Materials (ASTM) Test Method D1557. Class 2 Aggregate Base shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall 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 shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. If pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. No. 45283 0 59 k EXP.J''/cf jm or Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. William D. Olson, RCE 45283 Senior Project Engineer A29iJ Randall K. WagnerfEG 1612 Senior Associate r 1sikED GE No. 1612 * CERTIFIED * ENGINEERING Attachments: Appendix A - Laboratory Testing Procedures and Test Results Distribution: (2) Addressee Lennar Communities, Attention: Mr. Jim Urbina City of Carlsbad, Public Works Department, Attention: Mr. Don Moore (1) J. T. Kruer, Attention: Chuck Knight -3- Leighton 971009-020 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. The 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 Sample Location Sample Description R-Value R-47 Muirfields Drive, Yellow brown sandy SILT with clay 19 Station No. _3+25 R-82 Peppertree Way, Olive brown CLAY 13 Station No. _3+35 R-87 Edendale Street, Olive CLAY 18 Station No. 9+75 R-88 Edendale Street, Olive CLAY 15 Station No. _7+00 R-92 Heritage Drive, Yellow brown Silty SAND 42 Station No. _8+50 R-93 Heritage Drive, Yellow brown Silty SAND 31 _10+3 Station No. 5 R-94 Huntington Drive, Olive Brown CLAY with Sand 18 Station No. _3+75 R-96 Muirfields Drive, Yellow brown Silty SAND 38 Station No. _8+50 R-102 Astoria Street, Yellow brown Clayey SAND 24 Station No. _9+50 A-i Leighton CITY OF CARLSBAD /APPROVED WITH ADDITIONS I/ic/4 BY DATE Project No. 971009-011 To: Lennar Communities 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention Ms. Kristine Zortman Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY July 16, 2004 (revised July 28, 2004) Subject: Pavement Section Design Recommendations for El Fuerte Street, Station No. 29+00 to 57+50, Bressi Ranch, 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 Leighton and Associates, 2004a, Pavement Section Design Recommendations for El Fuerte Street (North of Poinsettia Lane to the North End of PA-13), Station No. 34+00 to 57+50, Bressi Ranch, Carlsbad, California, Project No. 971009-011, dated March 31, 2004, revised April 13, 2004 Pavement Section Design Recommendations for El Fuerte Street (Bressi Ranch Way to the North End of PA-13), Station No. 21+50 to 34+00, Bressi Ranch, Carlsbad, California, Project No. 971009-011, dated April 8, 2004 Project Design Consultants (PDC), 2003, Plans for the Improvement of El Fuerte Street, Carlsbad, California, Project No. CT-00-06, Drawing No. 400-8E, 23 Sheets, dated February 21, 2003 (revised July 15, 2003) Introduction This letter presents our preliminary pavement design recommendations for both sides of El Fuerte Street between Station No. 29+00 and 57+50 within the Bressi Ranch project, located in Carlsbad, California. This letter has been revised so that the preliminary pavement design is applicable to both sides of the street rather then just the western side. Preliminary pavement recommendations 3934 Murphy Canyon Road, Suite B205 a San Diego, CA 92123-4425 858.292.8030 m Fax 858.292.0771 m www.leightongeo.com 971009-011 concerning the eastern side of the street were previously provided in our letters dated March 31, 2004/revised April 13, 2004 (Leighton, 2004a) and April 8, 2004 (Leighton, 2004b). This letter has been revised so that it supercedes our previous letters (Leighton, 2004a and 2004b). Six representative subgrade soil samples were obtained along the roadway alignment. 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 from 6 to 9. The approximate sample locations and results of the laboratory testing are presented in Appendix A. It should be noted that for subgrade samples with an R-value less that 12, the City of Carlsbad requires further testing with lime and an engineering evaluation for the implementing lime treatment. Based on the project Improvement Plans (PDC, 2003), we understand that El Fuerte Street has a traffic index (TI) of 8.0. According to the City of Carlsbad requirements (Carlsbad, 1996), the minimum pavement section for streets having a TI of 8.0 is 5.0 inches of Asphalt Concrete (AC) over 6 inches of Aggregate Base (AB) regardless of the R-Value. The minimum lime-treated subgrade soil thickness is 8 inches regardless of the R-Value. In summary, the following sections address the City's requirement and present the recommended or preferred pavement design sections. Pavement Section Utilizing Class 2 Aggregate Base Material Based on the proposed street information, Class 2 Aggregate Base pavement sections were calculated using the Caltrans Highway Design Manual Method and compared with the City of Carlsbad's minimum section thickness requirements. The calculated pavement sections are presented on Table 1. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Asphalt Class 2 Location Traffic Design Concrete Aggregate Base Index R-Value Thickness Thickness (inches) (inches) El Fuerte Street Station No. 8.0 6 5.0 J9.o 29+00 and 57+50 Prior to placemeq 2f t stet aggregate base material, the upper 12 inches of subgrade soils in the street (includint—bPWtfre curb and gutter) shall be scarified, moisture-conditioned (or dried back) as necessary 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. -2- 4 Leighton 971009-011 Class 2 Aggregate Base shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall 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 shall 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 The following pavement section utilizes a lime-treated subgrade in accordance with the City of Carlsbad requirements. The R-Values having a value of less than 12 (i.e. Sample Nos. 64 through 69) were tested for optimum lime content (per American Standard of Testing and Materials [ASTM] Test Method C977) and soluble sulfate content (in accordance with Caltrans Test No. 417). The optimum lime content was determined to be 4-percent quick lime while the soluble sulfate content was found to be approximately 0.1 percent. After the lime was added to Samples Nos. 64 through 69 and allowed to cure a minimum of 24 hours, testing of the lime treated samples resulted in a minimum R-value of 83. Based on the proposed street information, the 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 pavement section is presented on Table 2. Table 2 Pavement Section Utilizing Lime Treated Subgrade Soils Traffic Design AC Class 2 Base Lime Treated Location Index R-Value Thickness Thickness Subgrade Layer (inches) (inches) (inches) El Fuerte Street Station No. 29+00 and 57+50 8.0 83 5.0 6.0 8.0 Prior to placement of the ,hatncrete and Class 2 Aggregate Base, the upper 8 inches of the subgrade soils (including. 'fIcurb and gutter) shall be scarified, moisture-conditioned to at least optimum moisture content, and thoroughly mixed with 4-percent quick lime (or the equivalent percentage of hydrated lime-slurry). After setting for a minimum of 24 hours, the thoroughly mixed lime-treated subgrade soils shall be compacted to a minimum 95 percent relative compaction based on ASTM Test Method D1557. After the lime-treated subgrade soils are compacted, we -3- 4 Leighton 971009-011 recommend that a curing compound be applied to the surface of the lime-treated subgrade soils and the materials allowed to cure. After the completion of the curing period, a minimum of 6 inches of Class 2 Aggregate Base shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 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 aggregate base material, a minimum of 5.0 inches of asphalt concrete shall be placed. Asphalt Concrete, Aggregate Base, and lime-treated subgrade soils shall 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. Recommended Pavement Section Based on our experience with similar soils in the vicinity of subject site, we recommend that the pavement section for El Fuerte Street between Station No. 29+00 and 57+50, utilize the AC and Class 2 Aggregate Base pavement section with no lime treatment of the subgrade soils, as discussed above. In summary, we have found that the lime treatment effectiveness of relatively thin layers of subgrade soils consisting of lean silty clays and sandy clays is very sensitive to changes in the soil particle size, and ultimately susceptible to potential cracking during the curing process. Therefore, it is our opinion that utilizing the AC and Class 2 Aggregate Base pavement section, as presented Table 1, will result in a better performing street pavement section. We also recommend that if the pavement is planned adjacent to landscaped areas, appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. -4- 4 Leighton 971009-011 If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. lvl-,b( ~-- William D. Olson, RCE 45283 Senior Project Engineer ' K lp II * Randall ' I K. 12 .No. 1612 CERTIFIED, Project Engineer ENGINEERING I ;LIs) CAt. ..# Attachments: Appendix A - Laboratory Testing Procedures and Test Results Distribution: (2) Addressee Lennar Communities, Attention: Mr. Jim Urbina City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt (1) J. T. Kruer, Attention: Mr. Chuck Knight (1) Hazard Construction Company, Attention: Mr. Lino Cruz -5- Leighton 971009-Oil 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. The 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 Sample Location Sample Description R-Value El Fuerte Street, Station R-64 Olive lean clay 8 No._30+50 El Fuerte Street, Station R-65 Olive lean clay 9 No. 37+50 El Fuerte Street, Station R-66 Olive lean clay 8 No. 41+00 El Fuerte Street, Station R-67 Olive brown lean clay 7 No. 46+50 El Fuerte Street, Station R-68 Olive brown lean clay 6 No. 52+00 El Fuerte Street, Station R-69 Brown lean clay 9 No. 55+50 R-64A El Fuerte Street, Station Olive lean clay and 4-percent 86 No. 30+50 lime El Fuerte Street, Station R-65A Olive lean clay 4-percent lime 86 No. 37+50 El Fuerte Street, Station R-66A Olive lean clay 4-percent lime 86 No. _41+00 El Fuerte Street, Station Olive brown lean clay 4- R-67A No. 46+50 percent lime 83 R-68A El Fuerte Street, Station Olive brown lean clay 4- 86 No. 52+00 percent lime R-69A El Fuerte Street, Station Brown lean clay 4-percent 88 No. 55+50 lime A-i Leighton (t GARLJAD APPROVED DATE Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY April 23, 2004 Project No. 971009-024 To: Lennar Communities 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention: Ms. Kristine Zortman Subject: Pavement Section Design Recommendations for Palmetto Drive and a Portion of Live Oaks Dive and Plumeria Drive, Planning Area PA-12, Bressi Ranch, 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 (PDC), 2004, Plans for the Improvement of Bressi Ranch Planning Area 12, Carlsbad, California, Drawing No. 413-2, 11 Sheets, dated February 3, 2004 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for Palmetto Drive and a portion of Live Oaks Dive (between Station No. 1+00 and 2+85) and Plumeria Drive (between Station No. 1+00 and 2+90) within Planning Area PA-12 of the Bressi Ranch project located in Carlsbad, California. Three representative subgrade soil samples were obtained along the roadway alignments. 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 from 23 to 26. The approximate sample locations and results of the laboratory testing are presented in Appendix A. Based on the project Improvement Plans (Project Design Consultants, 2004), we understand that Palmetto Drive, Live Oaks Dive, and Plumeria Drive have traffic indexes (TI) of 6.0. According to 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030w Fax 858.292.0771 w www.leightongeo.com 9711090-024 the city requirements (Carlsbad, 1996), the minimum pavement section for streets having a TI of 6.0 is 4.0 inches of Asphalt Concrete (AC) over 6.0 inches of Aggregate Base (AB) regardless of the R-Value. 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 sections are presented on Table 1. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Asphalt Concrete Class 2 Location Traffic Design Thickness Aggregate Base Index R-Value (in inches) Thickness (in inches) Palmetto Drive, Live Oaks Drive (Station No. 1+00to2+85), 6.0 23 4.0 10.0 and Plumeria Drive (Station No. 1+00 to 2+90) Prior to placement of the street aggregate base material, the upper 12 inches of subgrade soils in the street (including beneath the curb and gutter) shall be scarified, moisture-conditioned (or dried back) as necessary 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 shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall 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 shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. -2- 4 Leighton 9711090-024 If pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, No. 45283 M - 6.o§/ Or LEIGHTON AND ASSOCIATES, INC. _ William D. Olson, RCE 45283 Senior Project Engineer 4W K terrEGRandall K. W 1612 Senior Associate ii,,IED CIE GL K. . No. 612 * CERTiFIED * ENGINEERING GEOLOGIST OF r (2) Addressee 31.0' Lennar Communities, Attention: Mr. Jim Urbina City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt (2) J. T. Kruer, Attention: Chuck Knight -3- 4 Leighton Attachments: Appendix A - Laboratory Testing Procedures and Test Results Distribution: 971009-024 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 Sample Location Sample Description R-Value Live Oaks Drive, Station R-38 Light brown clayey SAND 23 No. 1+50 Palmetto Drive, Station R-39 Light brown clayey SAND 25 No. 3+65 Palmetto Drive, Station R-40 Light brown clayey SAND 26 No. 8+95 A-i APPROVED WITH ADDITiONS L9/oi BY DATE Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY April 15, 2004 Project No. 971009-018 To: Lennar Communities 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention: Ms. Kristine Zortman Subject: Pavement Section Design Recommendations for Alverton Drive and a Portion of Discovery Road, Planning Area PA-6, Bressi Ranch, 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 (PDC), 2003, Plans for the Improvement of Bressi Ranch Planning Area 6, Carlsbad, California, Drawing No. 413-1, 7 Sheets, dated November 12, 2003 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for Alverton Drive and a portion of Discovery Road (between Station No. 6+00 and 11+50) within Planning Area PA-6 of the Bressi Ranch project located in Carlsbad, California. Two representative subgrade soil samples were obtained along the roadway alignments. 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 from 17 to 19. The approximate sample locations and results of the laboratory testing are presented in Appendix A. Based on the project Improvement Plans (Project Design Consultants, 2003), we understand that Alverton Drive and Discovery Road have Traffic Indexes (TI) of 6.0. According to the city requirements (Carlsbad, 1996), the minimum pavement section for streets having a TI of 6.0 is 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 m www.leightongeo.com 9711090-018 4.0 inches of Asphalt Concrete (AC) over 6.0 inches of Aggregate Base (AB) regardless of the R- Value. 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 sections are presented on Table 1. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Traffic Design Asphalt Concrete Class 2 Aggregate Base Location ....- Index R-Value Thickness Thickness (in inches) (in inches) Alverton Drive and Discovery 6.0 17 4.0 11.0 Road (Station No. 6+00 to 11+50) Prior to the placement of the street aggregate base material, the upper 12 inches of the subgrade soils in the street (including beneath the curb and gutter) shall be scarified, moisture-conditioned (or dried back) as necessary 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 shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method Dl 557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall 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 shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. If pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. -2- 4 Leighton 9711090-018 If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. 83Cz rn wi CIVI c\ William D. Olson, RCE 45283 Senior Project Engineer DckL Randall K.Wagn r ,CEG 1612 ED GSn,.. Senior Associate K No. 1612 Attachments: Appendix A - Laboratory Testing Procedures and Test Results * EN CERTIFIED GINEERING * GEOLOGIST Distribution: (2) Addressee OFCAt Lennar Communities, Attention: Mr. Jim Urbina ' 3" City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt (2) J. T. Kruer, Attention: Chuck Knight Leighton -3- 971009-018 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 Sample Location Sample Description R-Value R-33 Alverton Drive, Station No. 3+00 Light brown clayey to silty SAND 17 R-34 Discovery Road, Station No. 9+00 Light brown clayey to silty SAND 19 A-i Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY April 8, 2004 (revised April 13, 2004) Project No. 971009-022 To: Lennar Communities 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention: Ms. Kristine Zortman Subject: Pavement Section Design Recommendations for Lismore Place and a Portion of Arundel Avenue and Alverton Drive, Planning Area PA-10, Bressi Ranch, 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 (PDC), 2003, Plans for the Improvement of Bressi Ranch Planning Area 10, Carlsbad, California, Drawing No. 413-1, 11 Sheets, dated November 19, 2003 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for Lismore Place and a portion of Arundel Avenue (between Station No. 1+00 and 4+75) and Alverton Drive (between Station No. 5+50 and 9+00) within Planning Area PA- 10 of the Bressi Ranch project located in Carlsbad, California. Two representative subgrade soil samples were obtained along the roadway alignments. 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 from 23 to 33. The approximate sample locations and results of the laboratory testing are presented in Appendix A. 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 9711090-022 Based on the project Improvement Plans (Project Design Consultants, 2003), we understand that Lismore Place, Arundel Avenue, and Alverton Drive have traffic indexes (TI) of 6.0. According to the city requirements (Carlsbad, 1996), the minimum pavement section for streets having a TI of 6.0 is 4.0 inches of Asphalt Concrete (AC) over 6.0 inches of Aggregate Base (AB) regardless of the R-Value. 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 sections are presented on Table 1. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Asphalt Concrete Class 2 Location Traffic Design Thickness Aggregate Base Index R-Value (in inches) Thickness (in inches) Lismore Place and Arundel Avenue 6.0 23 4.0 10.0 (Station No. 2+50 to 4+75) Arundel Avenue (Station No. 1+00 to 2+50) and Alverton Drive 6.0 33 4.0 7.0 (Station No. 5+50 to 9+00) Prior to placement of the street aggregate base material, the upper 12 inches of subgrade soils in the street (including beneath the curb and gutter) shall be scarified, moisture-conditioned (or dried back) as necessary 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 shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall 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 shall -2- 4 Leighton 9711090-022 conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. If pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. Ess,o No. 45283 rn Senior Project Engineer William D. Olson, RCE 45283 WA K4~-~ Randall K. W Senior Associate UENGINEERING Attachments: Appendix A - Laboratory Testing Procedures and Test Results * Distribution: (2) Addressee Lennar Communities, Attention: Mr. Jim Urbina City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt r (2) J. T. Kruer, Attention: Chuck Knight -3- Leighton V. V 971009-022 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 Sample Location Sample Description ] R-Value Alverton Drive, Station R-28 Light brown clayey SILT 33 No. 7+25 Lismore Place, Station R-29 Light brown clayey SILT 23 No. 4+00 A-i Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY February 24, 2004 (revised March 9, 2004) Project No. 971009-017 To: Lennar Communities 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention: Mr. Michael Ugar Subject: Pavement Section Design Recommendations for Town Garden Road (from El Camino Real to Alicante Road), Station No. 1+60 to 19+00, Bressi Ranch, Oceanside, 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 (PDC), 2003, Plans for the Improvement of Bressi Ranch Residential (Backbone Streets), Carlsbad, California, Drawing No. 400-8, 29 Sheets, dated April 10, 2003 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for Town Garden Road (from El Camino Real to Alicante Road), Station No. 1+60 to 19+00 in Carlsbad, California. Three representative subgrade soil samples were obtained along the roadway alignment. The samples were transported to our laboratory and R-value testing (in accordance with CaltransTest Method 301) was performed. The test results indicated the subgrade soils have R-values ranging from 17 to 60. The approximate sample locations and results of the laboratory testing are presented in Appendix A. Based on the project Improvement Plans (Project Design Consultants, 2003), we understand that Town Garden Road has a traffic index (TI) of 6.0. According to the city requirements (Carlsbad, 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 9711090-017 1996), the minimum pavement section for streets having a TI of 6.0 is 4 inches of Asphalt Concrete (AC) over 6 inches of Aggregate Base (AB) regardless of the R-Value. 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 sections are presented on Table 1. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Traffic Design Asphalt Concrete Class 2 Aggregate Base Location Index R-Value Thickness Thickness (in inches) (in inches) Town Garden Road, Station No. 1+60 to 4+50 6.0 60 4.0 6.0 Town Garden Road, Station No. 6.0 17 4.0 11.0 4+50 to 19+00 Prior to placement of the Street aggregate base material, the upper 12 inches of subgrade soils in the Street (including beneath the curb and gutter) shall be scarified, moisture-conditioned (or dried back) 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 shall be 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall 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 shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. -2- 4 Leighton 9711090-017 If pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, D. LEIGHTON AND ASSOCIATES, INC. No. 283 rn EqM Z-0 4/ILO &'__- CIV I William D. Olson, RCE 45283 Senior Project Engineer Randall K. Wagner, CEG 1612 :K.:l Senior Associate No. 1642 II*ia: M CERTIFIED mI* X t ENGINEERING / Attachments: Appendix A - Laboratory Testing Procedures and Test Results GEOLOGIST Distribution: (4) Addressee Lennar Communities, Attention: Mr. Jim Urbina City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt (1) J. T. Kruer, Attention: Chuck Knight -3- Leighton fl74 fSflfl ni n f I 1UUUIj Laboratory Testinci Procedures and Test Results "R"-Value: The resistance "R"-value was determined by theCalifornia 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 Sample Location Sample Description R-Value - P. 4 Town Garden Road, Station Light Brown Sandy 17 No. 9+20 CLAY - R 5 Town Garden,Road, Station Light Brown Silty Fine 60 No. 2+90 SAND Town Garden Rôd, Station R-6 No. 14+60 Light Clayey SILT 26 - A-i CITY OF CARLSBAD APPROVED 0 WITH ADDITIONS BY DATE Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY February 23, 2004 (revised March 10, 2004) Project No. 971009-013 To: Lenriar Communities 1525 Faraday Avenue, Suite 300 Carlsbad, California 92008 Attention: Mr. Michael Ugar Subject: Pavement Section Design Recommendations for El Camino Real Widening, East Side of El Camino Real Between Station No. 298+14 and 316+57, Bressi Ranch, Oceanside, 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 (PDC), 2003, Improvement Plans for El Camino Real, Carlsbad, California, Drawing No. 400-8G, 16 Sheets, dated June 24, 2003 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for the widening of the east side of El Camino Real between Station No. 298+14 and 316+57 in Carlsbad, California. Three representative subgrade soil samples were obtained along the eastern side of the El Camino Real alignment. 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 soil have R-values ranging from 7 to 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, 2003), we understand that El Camino Real has a traffic index (TI) of 9.0. According to the city requirements (Carlsbad, 1996), the minimum pavement section for streets having a TI of 9.0 is 6 inches of Asphalt Concrete (AC) over 6 inches of Aggregate Base (AB) regardless of the R-Value. 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 9711090-013 Pavement Section Utilizing Class 2 Acigregate 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 sections are presented on Table 1. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Asphalt Concrete Class 2 Location Traffic Design Thickness Aggregate Base Index R-Value (in inches) Thickness (in inches) El Camino Real, Station No. 9.0 21 6 15 298+14 to 309+00 El Camino Real, Station No. 9.0 9 6 19 309+00 to 316+57 Prior to placement of the street aggregate base material, the upper 12 inches of subgrade soils in the street (including beneath the curb and gutter) shall be scarified, moisture-conditioned (or dried back) as necessary 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 shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutter and extend a minimum of 6 inches behind the back of the curb. The Class 2 Aggregate Base shall 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 shall conform to and be placed in accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. If pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the amount of landscape irrigation to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. -2- 4 Leighton 9711090-013 Pavement Section Utilizing Lime-Treated Subgrade Soils The following pavement design recommendations utilizing a lime-treated subgrade section are provided in accordance with the City of Carlsbad guidelines. Based on our experience with similar soils on nearby sites within the City of Carlsbad, soils having an R-Value of less than 12 were previously tested 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 samples resulted in a minimum R-value of 69. Based on the above information, the 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 pavement section is presented on Table 2. Table 2 Pavement Section Utilizing Lime Treated Subgrade Soils Lime Treated Location Traffic Design AC Thickness Class 2 Base Thickness Subgrade Index R-Value (in inches) Layer (in inches) in inches) El Camino Real, Station 9.0 9.0 6 6 14 No. 309+00 to 316+57 Prior to placement of the asphalt concrete and Class 2 Aggregate Base, the upper 14 inches of the subgrade soils (including beneath the curb and gutter) shall 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 shall be compacted to a minimum 95 percent relative compaction based on ASTM Test Method D1557. After the minimum 95 percent relative compaction is achieved for the lime-treated subgrade soils, we recommend that a curing compound be applied to the surface of the lime-treated subgrade soils and the materials allowed to cure. After the completion of the curing period, a minimum of 6 inches of Class 2 Aggregate Base shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. The aggregate base material shall be a maximum of 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 6 inches of asphalt concrete shall be placed. Asphalt Concrete, Aggregate Base, and lime-treated subgrade soils shall conform to and be placed in accordance with: I) 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 -3- 4 Leighton 9711090-013 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. If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. No. 28 rn CIVN William D. Olson, RCE 45283 Senior Project Engineer 0 W '_ Randall K. Wag 1r, CEG 1612 Senior Associate Attachments: Appendix A - Laboratory Testing Procedures and Test Results 1612 M * CERTiFIED * ENGINEERING p GEOLOGIST . Distribution: (4) Addressee OF CA%.0 Lennar Communities, Attention: Mr. Jim Urbina 5 City of Carlsbad, Public Works Department, Attention: Mr. Casey Arndt q' (2) JT Kruer, Attention: Mr. Steve Lobaugh -4- Leighton 971009-013 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 Sample Location Sample Description R-Value R-1 El Camino Real, Station No. Light Brown Sandy 9 311+00 CLAY R-2 El Camino Real, Station No. Light Brown Clayey 23 .305+00 SAND R-3 El Camino Real, Station No. Light Brown Clayey 21 299+50 SAND A-i