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HomeMy WebLinkAboutCT 00-06; BRESSI RANCH; 2005 PAVEMENT SECTION DESIGN RECOMMENDATIONS (VARIOUS DATES); 2005-01-06ri c-rOO .O( Leighton and Associates, Inc. A LEGHTONGROUP COMPANY May 24, 2005 Project No. 971009-016 CITY OF CARLSBAD To: Sares Regis Group 18802 Bardeen Avenue Irvine, California 92612 Attention: Mr. Patrick Russell APER ED I I'AWITH ADDITIONS BY DATE Subject: Pavement Section Design Recommendations for a Portion of Gateway Road, Between Station No. 11+00 and 20+65, Bressi Ranch, Carlsbad, California References: Carlsbad, City of, 2004, Engineering Standards, Volumes I and 3, City of Carlsbad, California, dated June 2004 Project Design Consultants (PDC), 2004, Plans for the Improvement of Bressi Ranch Industrial, Carlsbad, California, Drawing No. 400-813, 25 Sheets, dated April 14, 2003, revised August 11, 2004 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for a portion of Gateway Road (between Station No. 11+00 and 20+65) that is directly south of Palomar Airport Road and east of El Fuerte Street 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 7 to 9. 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 Gateway Road has a Traffic Index (TI) of 7.0. According to the City of Carlsbad requirements (Carlsbad, 2004), the minimum pavement section for a street having a TI of 7.0 is 4 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 971009-016 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 CarlsbadTs minimum section thickness requirements. The recommended pavement sections are presented on Table 1. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Asphalt Class 2 Location Traffic Design R-Value Concrete Aggregate Base Index Thickness Thickness (in inches) (in inches) Gateway Road 7.0 7 4.0 16.0 (Station No. 11+00 to 20+65) 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- Leighton 971009-016 Pavement Section Utilizing Lime-Treated Subgrade Soils The following pavement section utilizes a lime-treated subgrade in accordance with the City of Carlsbad requirements. A representative R-value sample having a value of less than 12 was tested for optimum lime content (per ASTM Test Method C977) and soluble sulfate content (in accordance with Caltrans Test No. 417). The test results indicated the optimum lime content was determined to be 6-percent quick lime while the soluble sulfate content was found to be approximately 0.09 percent. After the lime was added to the sample and allowed to cure a minimum of 24 hours, testing of the lime treated sample resulted in a minimum R-value of 68. 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 Class 2 Lime Treated Traffic Design AC Base Subgrade Location Index R-Value Thickness Thickness Layer (inches) (inches) (inches) Gateway Road 7.0 68 4.0 6.0 (Station No. 11+00 to 20+65) it Prior to placement of the asphalt concrete and Class 2 Aggregate Base, the uppeches 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 6-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, 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 aggregate base material, a minimum of 4.0 inches of asphalt concrete shall be placed. -3- 4 Leighton * 971009-016 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 on the subject site, we recommend that the pavement sections for Gateway Road (between Station No. 11+00 to 20+65) utilize the Class 2 Aggregate Base Material with no lime treatment of the subgrade, as discussed above. In summary, it has been our professional experience that relatively thin lime-treated subgrade soil sections are very sensitive to moisture variations during the curing process and ultimately may be susceptible to minor cracking. In addition, it has been our experience that relatively thin lime-treated lean silty clays and sandy clays (which are present on the Bressi Ranch project) are also susceptible to heaving conditions that can result in asphalt concrete cracking and distress. Therefore, it is our opinion that utilizing the Class 2 Aggregate Base Material pavement design, as presented on Table 1, will result in a better performing pavement section. 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. Randall K. Wagner, CEG 1612 N o. 1612 OEATIFIED Senior Associate Geologist ENGINEERING I GEOLOGIST 4 Attachments: Appendix A - Laboratory Testing Procedures and Test Results Distribution: (2) Addressee (2) City of Carlsbad, Public Works Department, Attention: Casey Arndt J. T. Kruer, Attention: Chuck Knight Hazard Construction, Attention: Lantz Gibson -4- Leighton 971009-016 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-171 Gateway Road, Station No. 13+00 Brown sandy lean 7 CLAY R-157 Gateway Road, Station No. 17+00 Brown sandy lean 9 CLAY A-i c1i-,o .o, Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY May 11, 2005 To: Sares Regis Group 18802 Bardeen Avenue Irvine, California 92612 Attention: Mr. Patrick Russell Project No. 971009-016 CITY OF CARLSBAD APPROVED- F1 WITH ADDITIONS Subject: Pavement Section Design Recommendations for Metropolitan Street, Campbell Place, Colt Place, Slater Place, and a Portion of Gateway Road Between Station No. 10+60 and 31+00 and Alicante Road Between Station No. 113+15 and 120+00, Bressi Ranch, Carlsbad, California References: Carlsbad, City of, 2004, Engineering Standards, Volumes 1 and 3, City of Carlsbad, California, dated June 2004 Project Design Consultants (PDC), 2004a, Plans for the Improvement of Bressi Ranch Industrial, Carlsbad, California, Drawing No. 400-813, 25 Sheets, dated April 14, 2003, revised August 11, 2004 2004b, Plans for the Improvement of Bressi Ranch Industrial, Carlsbad, California Tract No. 02-15, Carlsbad, California, Drawing No. 421-3, 20 Sheets, dated October 13, 2004 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for Metropolitan Street (between Station No. 1+30 and 3+85); Campbell Place (between Station No. 0+50 and 7+85); Colt Place (between Station No. 1+25 and 5+60); Slater Place (between Station No. 0+45 and 3+80); and a portion of Gateway Road (between Station No. 10+60 and 31+00) and Alicante Road (between Station No. 113+15 and 120+00) in Carlsbad, California. Eleven representative subgrade soil samples were obtained along the roadway alignments. The samples were transported to our laboratory and R-value testing (in accordance with 3934 Murphy Canyon Road, Suite B205. San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com lu 971009-016 Caltrans Test Method 301) was performed. The test results indicated the subgrade soils have R- values ranging from 5 to 33. The approximate sample locations and results of the laboratory testing are presented in Appendix A. Based on the project Improvement Plans (referenced above), we understand that the streets have a Traffic Index (TI) of 7.0. According to the City of Carlsbad requirements (Carlsbad, 2004), the minimum pavement section for streets having a TI of 7.0 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. The Caltrans Highway Design Manual Method calculations for Metropolitan Street and Colt Place are presented in Appendix B. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Traffic Design R- Asphalt Concrete Class 2 Aggregate Location Index Value Thickness Base Thickness (in inches) (in inches) Gateway Road (Station 7.0 15 4.0 14.0 No. 10+60t031+00) Alicante Road (Station 7.0 12 4.0 14.0 No. 113+15 to 120+00) Metropolitan Street 7.0 9 4.0 15.0 Campbell Place 7.0 27 4.0 11.0 Colt Place 7.0 6 4.0 16.0 Slater Place 7.0 14 4.0 14.0 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) shall be scarified, moisture-conditioned (or dried Leighton 971009-016 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. 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 sample on Metropolitan Street having a value of less than 12 was tested for optimum lime content (per ASTM Test Method C977) and soluble sulfate content (in accordance with Caltrans Test No. 417). The test results indicated the optimum lime content was determined to be 5-percent quick lime while the soluble sulfate content was found to be approximately 0.10 percent. After the lime was added to the sample and allowed to cure a minimum of 24 hours, testing of the lime treated sample resulted in a minimum R-value of 60. Based on the proposed street information, the lime-treated pavement section for Metropolitan Street and Colt Place 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 Class 2 Lime Treated Traffic Design AC Base Subgrade Location Index R-Value Thickness Thickness Layer (inches) (inches) (inches) Metropolitan Street and 7.0 60 4.0 Colt Place al. 6.0 -3- Leighton 971009-016 (2. Prior to placement of the asphalt concrete and Class 2 Aggregate Base, the upper,Yinches 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 lime-treated subgrade soils are compacted, 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 aggregate base material, a minimum of 4.0 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: 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 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 on the subject site, we recommend that the pavement section for Metropolitan Street and Colt Place utilize the Class 2 Aggregate Base Material with no lime treatment of the subgrade, as discussed above. In summary, it has been our professional experience that relatively thin lime-treated subgrade soil sections are very sensitive to moisture variations during the curing process and ultimately may be susceptible to minor cracking. In addition, it has been our experience that relatively thin lime-treated lean silty clays and sandy clays (which are present on the Bressi Ranch project) are also susceptible to heaving conditions that can result in asphalt concrete cracking and distress. Therefore, it is our opinion that utilizing the Class 2 Aggregate Base Material pavement design, as presented on Table 1, will result in a better performing pavement section. 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. 4 -4- Leighton 971009-016 If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. of ES S/0 C')( No. 283 Exp._ii3 /O J Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. William D. Olson, RCE 45283 Senior Project Engineer 1tc K KLJ Randall K. Wagner, EG 161 Senior Associate Geologist A ED G K. IPA No. 1612 i'i * ( CERTIFIED * ENGINEERING Attachments: Appendix A - Laboratory Testing Procedures and Test Results Appendix B - Asphalt Pavement Section Design Calculations Utilizing Caltrans Class 2 Aggregate Base Distribution: (2) Addressee (2) City of Carlsbad, Public Works Department, Attention: Casey Arndt J. T. Kruer, Attention: Chuck Knight Hazard Construction, Attention: Lantz Gibson -5- Leighton 971009-016 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-158 Colt Place, Station No. 2+75 Yellow-brown lean CLAY R-160 Gateway Road, Station No. 13+00 Yellow-brown lean 15 CLAY _with _sand R-161 Gateway Road, Station No. 18+50 Yellow-brown clayey 32 SAND R-162 Gateway Road, Station No. 23+75 Yellow-brown lean 17 CLAY R- 163 Gateway Road, Station No. 28+25 Yellow-brown clayey 29 SAND R-164 Alicante Road, Station No. 115+00 Yellow-brown lean 12 CLAY R-165 Alicante Road, Station No. 118+00 Yellow-brown lean 17 CLAY R-166 Metropolitan Street, Station No. Yellow-brown lean 9 2+50 CLAY R-168 Campbell Place, Station No. 2+50 Yellow-brown clayey 33 SAND R-169 Campbell Place, Station No. 6+50 Yellow-brown clayey 27 _ SAND R-170 Slater Place, Station No. 2+25 Yellow-brown lean 14 CLAY A-i 97 1009-0 16 APPENDIX B Asphalt Pavement Section Design Calculations Utilizing Caltrans Class 2 Aggregate Base 1) Metropolitan Street (Station No. 1+30 to 3+85) I-i = Th"knecc GE = Gravel Equivalent Design Traffic Index = 7.0 Design Subgrade R-Value = 9 Class 2 Aggregate Base R-Value = 78, (based on Caltrans Standard Specifications, Section 26) Asphalt Concrete (AC) Layer GE,,, = (0.0032) (7.0) (100-78) + 0.20 = 0.70 feet Gfac 2.14 Hac = 0.70 feet x 12 in/ft = 3.9 inches 2.14 Use 4.0 inches of Asphalt Concrete (City of Carlsbad minimum) Actual GE of asphalt concrete layer = (4/12 feet) 2.14 = 0.71 feet Aggregate Base (AB) Layer GEotai = (0.0032) (7.0) (100-9) = 2.04 feet GEAB = 2.04 feet - 0.71 feet = 1.33 feet GFAn= 1.1 HAB= 1.33 feet 12 in/ft= 14.5 inches 1.1 Use 15.0 inches of Aggregate Base material Recommended Pavement Section 4.0 inches of asphalt concrete over 15.0 inches of Class 2, Recycled Class 2 or Crushed Miscellaneous Aggregate Base material (based on the City of Carlsbad Standards for Design and Construction of Public Works Improvements) B-i 971009-016 APPENDIX B (Continued) 2) Colt Place (Station No. 1+25 to 5+60) H = Thickness GE = Gravel Equivalent Design Traffic Index = 7.0 Design Subgrade R-Value = 5 Class 2 Aggregate Base R-Value = 78. (based on Caltrans Standard Specifications, Section 26) Asphalt Concrete (AC) Layer GEac = (0.0032) (7.0) (100-78) + 0.20 = 0.70 feet 2.14 Hac = 0.70 feet x 12 in/ft = 3.9 inches 2.14 Use 4.0 inches of Asphalt Concrete (City of Carlsbad minimum) Actual GE of asphalt concrete layer = (4/12 feet) 2.14 = 0.71 feet Aggregate Base (AB) Layer GEotai = (0.0032) (7.0) (100-5) = 2.13 feet GEAn = 2.13 feet - 0.71 feet = 1.42 feet GFAn= 1.1 HAB 1.42 feet 12 in/ft= 15.5 inches 1.1 Use 16.0 inches of Aggregate Base material Recommended Pavement Section 4.0 inches of asphalt concrete over 16.0 inches of Class 2, Recycled Class 2 or Crushed Miscellaneous Aggregate Base material (based on the City of Carlsbad Standards for Design and Construction of Public Works Improvements) Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY May 11, 2005 CITY To: Greystone Homes iJI!i I 1 525 Faraday Avenue, Suite 300 WITH ADDITIONS Carlsbad, California 92008 Attention: Mr. Keith Randhahn Subject: Pavement Section Design Recommendations for Alley 'NN', 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 Alley 'NN' within Planning Area PA-8 of the Bressi Ranch project located in Carlsbad, California. One representative subgrade soil sample was obtained along the alley alignment. The sample was 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 a representative R-value of 19. The approximate sample location and results of the laboratory testing are presented in Appendix A. Based on the project Improvement Plans (Project Design Consultants, 2004), we understand that Alley 'NN' 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. 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 971009-030 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. 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) Alley 'NN' L5.0 19 4.0 5.0 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 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. 4 -2- Leighton 971009-030 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. (No. 1612 " * t CERTIFIED j*O Randall K. '. ENGINEERING 1 II Wagner, C 1612 Senior Associate Geologist .06 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 971009-030 APPENDIX A LaboratoU 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 Sample Location Sample Description R-Value R-167 Alley, '', Station No. 3+00 J Yellow brown sandy 19 lean CLAY A-i Cq-eO O( Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY May 5, 2005 To: Sares Regis Group 18802 Bardeen Avenue Irvine, California 92612 Attention: Mr. Patrick Russell ect No. 9/IUU9-U! CITY OF CARLSBAD 13 WITH ADDITIONS Subject: Pavement Section Design Recommendations for a Portion of Gateway Road (East of El Fuerte Street) Between Station No. 1+50 and 11+00, Bressi Ranch, Carlsbad, California References: Carlsbad, City of, 2004, Engineering Standards, Volumes I and 3, City of Carlsbad, California, dated June 2004 Project Design Consultants (PDC), 2004, Plans for the Improvement of Bressi Ranch Industrial, Carlsbad, California, Drawing No. 400-813, 25 Sheets, dated April 14, 2003, revised August 11, 2004 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for a portion of Gateway Road (between Station No. 1+50 and 11+00) that is east of El Fuerte Street 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 13 to 18. 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 Gateway Road has a Traffic Index (TI) of 7.0. According to the City of Carlsbad requirements (Carlsbad, 2004), the minimum pavement section for a street having a TI of 7.0 is 4 inches of Asphalt Concrete (AC) over 6 inches of Aggregate Base (AB) regardless of the R-Válue. 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 971009-016 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 R- Asphalt Concrete Class 2 Aggregate Location Index Value Thickness Base Thickness (in inches) (in inches) Gateway Road (Station No. 7.0 13 4.0 14.0 1+50 to 11+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 Di 557. 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. 4 -2- Leighton 971009-016 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. Randall K. Wagner, CEG 1612 Senior Associate Geologist Attachments: Appendix A - Laboratory Testing Procedures and Test Results Distribution: (2) Addressee (2) City of Carlsbad, Public Works Department, Attention: Casey Arndt J. T. Kruer, Attention: Chuck Knight Hazard Construction, Attention: Lantz Gibson I. No. 1612 •i * 1 CERTIFIED J * ENGINEERING GEOLOGIST OF C It 3.3• -3- Leighton 971009-016 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-156 Gateway Road, Station No. 3+00 Yellow-brown lean 18 CLAY Gateway Road, Station -No. 10+00 Yellow-brown lean R-157 CLAY 13 Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY April 12, 2005 Project D09-016 CITY OF CARLSBAD To: Sares Regis Group 18802 Bardeen Avenue Irvine, California 92612 Attention: Mr. Patrick Russell 4 ~~ APPROVEQ WITH ADDITIONS el L2 f/Q Subject: Pavement Section Design Recommendations for Innovation Way and a Portion of Gateway Road Between Station No. 31+00 and 53+25, Bressi Ranch, Oceanside, California References: Carlsbad, City of, 2004, Engineering Standards, Volumes 1 and 3, City of Carlsbad, California, dated June 2004 Project Design Consultants (PDC), 2004, Plans for the Improvement of Bressi Ranch Industrial, Carlsbad, California, Drawing No. 400-813, 25 Sheets, dated April 14, 2003, revised August 11, 2004 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for Innovation Way (between Station No. 1+25 and 11+20) and a portion of Gateway Road (between Station No. 31+00 and 53+25) in Carlsbad, California. Seven 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 less than 5 to 12. 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 Innovation Way and Gateway Road have a Traffic Index (TI) of 7.0. According to the City of Carlsbad requirements (Carlsbad, 2004), the minimum pavement section for streets having a TI of 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 971009-016 7.0 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. The Caltrans Highway Design Manual Method calculations are presented in Appendix B. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Traffic Design R- Asphalt Concrete Class 2 Aggregate Location Index Value Thickness Base Thickness (in inches) (in inches) Innovation Way (Station 17.6 No. 5+50 to 11+20) and 7.0 5 4.0 Gateway Road (Station No. 35+50 to 53+25) Innovation Way (Station No. 1+25 to 5+50) and 7.0 10 4.0 15.0 Gateway Road (Station No. 3 1+00 to 35+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 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 971009-016 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. One of the R-value samples having a value of less than 12 was tested for optimum lime content (per ASTM Test Method C977) and soluble sulfate content (in accordance with Caltrans Test No. 417). The test results indicated the optimum lime content was determined to be 6-percent quick lime while the soluble sulfate content was found to be approximately 0.09 percent. After the lime was added to the sample and allowed to cure a minimum of 24 hours, testing of the lime treated sample resulted in a minimum R-value of 68. 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 Class 2 Lime Treated Location Traffic Index Design R-Value AC Thickness Base Thickness Subgrade Layer (inches) (inches) (inches) Innovation Way and Gateway Road (Station No. 7.0 68 4.0 6.0 8.0 31+00 to 53+25) 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) shall be scarified, moisture-conditioned to at least optimum moisture content, and thoroughly mixed with 6-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, 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 -3. 4 Leighton 971009-016 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 4.0 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 on the subject site, we recommend that the pavement sections for Innovation Way and Gateway Road (between Station No. 3 1+00 to 53+25) utilize the Class 2 Aggregate Base Material with no lime treatment of the subgrade, as discussed above. In summary, it has been our professional experience that relatively thin lime-treated subgrade soil sections are very sensitive to moisture variations during the curing process and ultimately may be susceptible to minor cracking. In addition, it has been our experience that relatively thin lime- treated lean silty clays and sandy clays (which are present on the Bressi Ranch project) are also susceptible to heaving conditions that can result in asphalt concrete cracking and distress. Therefore, it is our opinion that utilizing the Class 2 Aggregate Base Material pavement design, as presented on Table 1, will result in a better performing pavement section. 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. -4- of Leighton 971009-016 If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. Respectfully submitted, ( K. ED\ GE0 LEIGHTON AND ASSOCIATES, INC. No. 1612 T * CERTIFIED .JO?J ENGINEERING II dGEoLoei:T Randall K. WagnerC G 1612 OF CAL%f Senior Associate Attachments: Appendix A - Laboratory Testing Procedures and Test Results Appendix B - Asphalt Pavement Section Design Calculations Utilizing Caltrans Class 2 Aggregate Base Distribution: (2) Addressee (2) City of Carlsbad, Public Works Department, Attention: Casey Arndt J. T. Kruer, Attention: Chuck Knight Hazard Construction, Attention: Lantz Gibson -5- Leighton 971009-016 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_j R-Value R-148 Innovation Way, Station No. 8+25 Pale brown lean Less than 5 CLAY Gateway Road, Station Dark gray lean R-149 No. 46+00 CLAY Less than 5 Gateway Road, Station Dark gray lean R-150 5 No. 50+50 CLAY R-151 Gateway Road, Station No. 33+10 Yellow-brown lean 10 CLAY R-152 Gateway Road, Station No. 37+50 Yellow-brown lean 8 CLAY R-153 Gateway Road, Station No. 42+00 Yellow-brown lean 7 CLAY R-154 Innovation Way, Station No. 3+10 Yellow-brown lean 12 CLAY A-i Leighton 971009-016 APPENDIX B Asphalt Pavement Section Design Calculations Utilizing Caltrans Class 2 Aggregate Base 1) Innovation Way (Station No. 5+50 to 11+20) and Gateway Road (Station No. 35+50 to 53+25) H = Thickness GE = Gravel Equivalent Design Traffic Index = 7.0 Design Subgrade R-Value = 5 Class 2 Aggregate Base R-Value = 78, (based on Caltrans Standard Specifications, Section 26) Asphalt Concrete (AC) Layer GEac = (0.0032) (7.0) (100-78) + 0.20 = 0.70 feet Gfac2.14 Hac = 0.70 feet x 12 in/ft = 3.9 inches 2.14 Use 4.0 inches of Asphalt Concrete (City of Carlsbad minimum) Actual GE of asphalt concrete layer = (4/12 feet) 2.14 = 0.71 feet Aggregate Base (AB) Layer GEtotai = (0.0032) (7.0) (100-5) = 2.13 feet GE= 2.13 feet-0.71 feet= 1.42 feet GFAB= 1.1 HAB = 1.42 feet x 12 in/ft = 15.5 inches 1.1 Use 16.0 inches of Aggregate Base material Recommended Pavement Section 4.0 inches of asphalt concrete over 16.0 inches of Class 2, Recycled Class 2 or Crushed Miscellaneous Aggregate Base material (based on the City of Carlsbad Standards for Design and Construction of Public Works Improvements) B-i Leighton 901128-018 APPENDIX B (continued) 2) Innovation Way (Station No. 1+25 to 5+50) and Gateway Road (Station No. 31+00 to 35+50) H = Thickness GE = Gravel Equivalent Design Traffic Index = 7.0 Design Subgrade R-Value = 10 Class 2 Aggregate Base R-Value = 78, (based on Caltrans Standard Specifications, Section 26) Asphalt Concrete (AC) Layer GEac = (0.0032) (7.0) (100-78) + 0.20 = 0.70 feet Gfac = 2.14 Hac0.70_ feet x 12 in/ft =3.9 inches 2.14 Use 4.0 inches of Asphalt Concrete (City of Carlsbad minimum) Actual GE of asphalt concrete layer = (4/12 feet) 2.14 = 0.71 feet Aggregate Base (AB) Layer GEtotat = (0.0032) (7.0) (100-10) = 2.02 feet GEAB = 2.02 feet - 0.71 feet = 1.31 feet GFAB = 1.1 HAB 1.31 feet 12 in/ft = 14.3 inches 1.1 Use 15.0 inches of Aggregate Base material Recommended Pavement Section 4.0 inches of asphalt concrete over 15.0 inches of Class 2, Recycled Class 2 or Crushed Miscellaneous Aggregate Base material (based on the City of Carlsbad Standards for Design and Construction of Public Works Improvements) Leighton 4"A Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY January 6, 2005 17 CITY OF CARLSBAD To: Lennar Communities I APPROVED 1525 Faraday Avenue, Suite 300 I 0 WITH ADDITIONS Carlsbad, California 92008 BY Attention: Mr. Sean Scholey Subject: Pavement Section Design Recommendations for the RV Parking Facility, Planning Area PA-13, 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 PA-13 RV Parking Plans, Conditional Use Permit CUP-04-20, 2 Sheets, dated September 27, 2004 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for the proposed RV parking area within Planning Area 13 of the Bressi Ranch project located in Carlsbad, California. Based on the project plans (PDC, 2004), a RV parking area and associated entry road for the future church site is proposed at the northern end of Planning Area PA-13 and west of El Fuerte Street. 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 9. The approximate sample location and result of the laboratory testing is presented in Appendix A. It should be noted that for subgrade samples with 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. 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 • www.leightongeo.com 971009-017 Based on the project plans (PDC, 2004), we have assumed that the RV parking area and associated entry road have a Traffic Index (TI) of 6. According to the city requirements (Carlsbad, 1996), the minimum pavement section for streets having a TI of 6 is 4 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 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. Table 1 Recommended Pavement Section Utilizing Class 2 Aggregate Base Asphalt Class 2 Location Traffic Index Design R- Concrete Aggregate Value Thickness Base Thickness (inches) (inches) PA- I 3 RV Parking Area 6 9 and Entry Road 4 13 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 D1 557. The aggregate base material shall be a maximum of 6 inches thick below the curb and gutters 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 971009-017 Pavement Section Utilizina Lime-Treated Subarade 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 4-percent quick lime while the soluble sulfate content was found to be 0.22 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 74. 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. Table 2 Pavement Section Utilizing Lime Treated Subgrade Soils Traffic Design R- AC Class 2 Base Lime Treated Location Index Value Thickness Thickness Subgrade (inches) (inches) Layer (inches) PA- 13 RV Parking Area 6 74 4 6 8 and Entry Road 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 4-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 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 -3- 4 Leighton 971009-017 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 PA-13 RV parking area and entry road utilize the Class 2 Aggregate Base Material design with no lime treatment of the subgrade soils, as discussed above. In summary, we have found that the relatively thin layers lime treatment subgrade soils, consisting of lean silty clays and sandy clays, are very sensitive to moisture changes in the soil, and ultimately susceptible to potentially minor cracking during the curing process. Therefore, it is our opinion that utilizing the Class 2 Aggregate Base Material pavement design, as presented Table 1, will result in a better performing pavement section. In addition, where 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. -4- 4 Leighton 971009-017 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. O\ç) v( No. 4283, Z Exp._gIif 0(0 J m William D. Olson, RCE 45283 Senior Project Engineer Lagner~, -_9,Randall K. CEG 1612 Senior Associate No. 1612 G.ERTIFIED * ENGINEERING GEOLOGIST Attachments: Appendix A - Laboratory Testing Procedures and Test Results OF ElLr Distribution: (2) Addressee (2) City of Carlsbad, Public Works Department, Attention: Mr. Rick Wotipka (1) Lennar Communities, Attention: Mr. Jim Urbina (1) Hofman Planning, Attention: Mr. Tony Sanfihippo -5- Leighton 971009-017 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 Location Sample Description R-Value PA- 13 RV Parking Area and Olive-brown lean CLAY 9 Entry Road PA- 13 RV Parking Area and Olive-brown lean CLAY 74 Entry Road with 4% Lime A-i Leighton