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Home My WebLink AboutCT 06-24; BRESSI RANCH VILLAGE CENTER; PAVEMENT SECTION DESIGN RECOMMENDATIONS; 2010-05-26Cl- O (o-4 RECEIVED JUN - 12010 ZNGIN Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY May 26, 2010 Project No. 971009-063 To: LNR Property Corporation 4350 Von Karman Avenue, Suite 200 Newport Beach, California 92660 Attention: Mr. Brian Payne Subject: Pavement Section Design Recommendations for Major B, Bressi Ranch Village Center, Carlsbad, California Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for the proposed parking areas and truck and auto driveways associated with the Major B project at Bressi Ranch Village Center located in Carlsbad, California. It should also be noted that we also reviewed our previously recommended pavement section designs for the site (Leighton, 2008) that were reviewed and approved by the city. As background, our previous pavement recommendations were based on R-value testing of sixteen representative subgrade soil samples obtained throughout the Bressi Ranch Village Center pavement areas. The test result indicates the subgrade soils have an R-value ranging from 22 to 60. For this current study, one representative subgrade soil samples was obtained within the proposed driveways and 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 26. The approximate location of the sample and results of the laboratory testing are presented in Appendix B. We have assumed that the truck driveways have a Traffic Index (TI) of 6.0, and the parking spaces have a TI of 4.5. According to the city requirements (Carlsbad, 2004), the minimum pavement section for streets having a TI of 4.5 is 4 inches of Asphalt Concrete (AC) over 4 inches of Aggregate Base (AB) while the minimum for streets having a TI of 6.0 is 4 inches of AC over 6 inches of AB regardless of the R-Value. 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 971009-063 Recommended Pavement Sections Utilizing Class 2 Aggregate Base Material Based on the above information, Class. 2, Aggregate Base material 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 Sections Utilizing Class 2 Aggregate Base Class lass 2 Traffic Design Concrete Aggregate Location Index R-Value Thickness Base (inches) Thickness (inches) Parking Spaces 4.5 26 4.0 4.0 Driveway and Truck Driveways 6.0 '26 4.0 10.0 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) shalt 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 D1557. Class 2 Aggregate Base shall then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D.1557. 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. 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. -2- Leighton / 7 971009-063 tyou have any questions regarding our letter, please contact this office. We appreciate this :Opportunity to be of service. • Respectfully submitted, • LEIGHTON AND ASSOCIATES, INC. .• /j1 civ /7 William D. Olson, RCE 45283 OFC Associate Engineer Attachments: Appendix A -References Appendix B - Laboratory Testing Procedures and Test Results Distribution: (2) Addressee (3) Grant General Contractor, Attention: M. John Sandahi APPENDIX A References Carlsbad, City of 2004, 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 June 2004. PDC, 2010, Precise Grading and Erosion Control Plans Bressi Ranch Village Commercial Major Building B, Carlsbad, California, 3 Sheets, dated February 9, 2010. Leighton and Associates, 2008, Pavement Section Design Recommendations for Bressi Ranch Village Center, Carlsbad, California, Project No. 971009-05 1, dated May 16, 2008. A-i 971009-063 APPENDIX B 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-1 Driveway Adjacent to Major "B" Yellow brown silty lean CLAY 26 B-i Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY June 23, 2008 Project No. 971009-051 To: LNR Property Corporation Commercial Property Group 4275 Executive Square, Suite 210 La Jolla, California 92037 Attention: Mr. Jeff Williams Subject: Alternative Pavement Section Design Recommendations Relative tothe Temporary Fire Access Roads, Bressi Ranch Village Center, Carlsbad,'Califoniia Reference: Leighton and Associates, Inc-, 2008, Pavement Section Design Recommendations - for Bressi Ranch Village Center, Carlsbad,- California, Project No. 971009-05 1, dated May 16, 2008 In. accordance with your request, this letter presents our alternative pavement design recommendations relative to the temporary fire access roads- that---will be cohstructedfor -the proposed Bressi Ranch Village Center project located in Carlsbad,Califomia. We:thderstaridthat the fire access roads will be placed prior to the start of the paving operations for the project. -And that the temporary fire access roads will consist of3 inches of asphalt' cOncrete (AC) over 95 percent compacted subgrade soils. We also understand that the permanent or fmal pavement section for the driveways, where the fire access roads will be placed is planned to 'consist of a minimum pavement section of 4 inches of AC over 10 inches of aggregate base material (Leighton, 2008'). From a geotechnical standpoint, the temporary..fire access road' ACpavement -may be left-in-place •"' . (rather than' being removed and hauled to a disposal area) and--- can become--part of the final pavement section for the project. Consequently, the recommended pavement sectiOn in the locatiOn of the temporary fire access roads can be 44nches of AC over 7-inches of aggregàte'base provided that the fire access road AC is in go ondition. Prior to covering the AC with aggregate base material, the geotechnical consultant evaluate the conditiOn of the fire access road and provide addendum recommendations;ned -o -4_ cc -.L. 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 971009-051 If you have any questions regarding our letter, please contact this Office. We appreciate this opportunity to be of service. Respectfully submitted, .. - LEIGI-ITON AND ASSOCIATES, INC. co Aly -I L. Exp. a jrn JJ William D. Olson, RCE 45283 Associate Engineer OF Randall K. Wagner, C G 1612 Principal Geologist Distribution: (2) Addressee Grant General Contractor, Attention: Mr. John.Sandahl City of Carlsbad Attention: Mr. Jay Jordon rOMAL Q4. No. 1612 * ENGINEERING JT/) °FCAL -4011, APPROVED SENT — MAY 232008 Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY May 16, 2008 Project No. 971009-051 To: LNR Property Corporation Commercial Property Group 4275 Executive Square, Suite 210 La Jolla, California 92037 Attention: Mr. Jeff Williams Subject: Pavement Section Design Recommendations for Bressi Ranch Village Center, Carlsbad, California Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for the proposed parking areas and truck and auto driveways of the Bressi Ranch Village Center project located in Carlsbad, California. In addition, this letter provides our addendum geotechnical recommendations concerning the concrete flatwork at the site. It should also be noted that this letter also presents the approved pavement section design (Leighton, 2008b) for the western side of the site that was previously sent to the city, reviewed, and approved. A total of sixteen representative subgrade soil samples were obtained within the proposed driveways and parking areas. The samples were 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 ranging from 22 to 60. The approximate locations of the samples are presented on Figure 1, Recommended Pavement Sections and R-Value Test Location Map while the results of the laboratory testing are presented in Appendix B. We have assumed that the truck driveways have a Traffic Index (TI) ãf 6.0, the 'auto driveways have -... .-a TI of 5.0, and the parking spaces have a TI of 4.5. According to the city requirements (Carlsbad, 2004), the minimum pavement section for streets having a TI of 4.5 and 5.0 is 4 inches of Asphalt Concrete (AC) over 4 inches of Aggregate Base (AB) while the minimum for streets having a TI of 6.0 is 4 inches of AC over 6 inches of AB regardless of the R-Value. 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 921234425 858.292.8030. Fax 858.292.0771 971009-051. Recommended Pavement Sections Utilizing Class 2 Aggregate Base Material Based on the above information, 'Class 2 Aggregate Base material 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 The locations of the recommended pavement sections are also shown on the Recommended Pavement Sections and R-Value Test Location Map (Figure 1). Table Recommended Pavement Sections Utilizing Class 2 Aggregate Base Asphalt Class 2 Traffic Design Concrete Aggregate Location .. Index. R-Value Thickness Base (inches) Thickness (inches) Parking Spaces 4.5 22 4.0 4.0 Auto Driveways North of the Main East-West Driveway and in the 5.0 25 4.0 4.0 Western Portion of the Site Auto Driveways South of the Main 50 22 4 0 5 0 East-West Driveway . Truck Driveways in the Western 60 32 4.0 70 Portion ofthe Site Truck Driveways on the Northern 60 29 40 80 Portion of the Site Main East-West Driveway and Truck Driveways on the Southern Portion of 6.0 .. 22 4.0 10.0 the Site . 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 a 2; percent over optimum moisture content and compacted to a minimum 95 percent relative compaction based on ASTM Test Method. D1557. , -2- , . •• Leightoh 971009-051. Class 2 Aggregate Base shall then.;be placed and comactéd at a minimum 95. percent relative compaction in accordance with ASTM Test Method D1557..The Class 2 Aggregate Base shall conform to and be placed m accordance with the lat&strevisioñ of the California Department of Transportation Standard Speäifications (Section 26), the Greenbook specifications and/or the City of Carlsbad requiièhients Asphalt Concrete shall conform to and be placed in accordance with the "G±enboOk" Standard Specificatio s for Public Works Cnstiiiction and' the City of Carlsbad requirements. - - - In addition, whèrè pavement is planned adjacent to landscaped areas, we recommend that appropriate measures be taken (such as keeping the athoiiht of landscape irrigatibn to a minimum, installing area drains or other devices, etc.) to reduce the possible adverse effects of water on the pavement subgrade. . Elimination of the Aggregate Base Beneath On-Site Cohcreté FlatwOrk and Curbs/Gutters Based on our experience with similar-soils in the vicinity of-the site, -itis our professional opinion that the on-site concrete flatwork and curbs/guttrs (outside the limits of the City of Carlsbad easements) can be placed directly on the properly processed subgrade soils without any significant, adverse affects We have found that concrete flatwork founded directly on the subgrade soils (and along with a turn-down edge) and curbs/gutters act as a bamer, which limits the migration of groundwater from storm water or, landscape irrigation water and thereby reduces the possible adverse effects of water on the pavement or subgrade soils. Therefore, we recommend that. the on-site r concrete flatWork curbs/gutters be placed directly on. properly processed subgrade soils The subgrade soils beneath the on-site concrete flatwork should be placed as recommended in the following conc'rete flatwork section Prior to the placement -of the on-it& curb/gutters, the upper 12 iñches',of the subgrade soils (including 6- inches behind the, curb arid gutter) should be scarified, moisthre-coñditioned to at least 3- percent over the optimum moisture content and compacted to a minimum 95 percent relative compaction based on ASTM Test Method D1557. - - - Concrete Flatwork Recommendations Due to the presenceof medium (to possibly) highlyexpansive soils, the on-site concrete flatwork is subject - to - adverse conditions, such as, unsightly draking, heaving, excessive.water vapor transmission, and efflórescence. Adherence to the following guidelines will help mitigate potential adverse conditions. 4- Leighton 971009-051 1) Expansive Subgrade Soils: In order to reduce the potential heaving of the subgrade soils, we recommend that the upper 12 to 18 inches of the subgrade soils be scarified and moisture conditioned to at least 6 percent over the optimum moisture content. After the upper 12 to 18 inches of the subgrade soils has been moisture conditioned, the subgrade soils should be recompacted to a relative compaction of between 85 to 88 percent. The concrete flatwork should be at least 4 inches thick. Concrete flatwork outside the City of Carlsbad easements can be reinforced with 6x6/1 0710 welded wire mesh. Expansion joints and/or saw-cuts crack joints should be designed so that the concrete flatwork consists of square panels with a maximum dimension ranging from 4 to 5 feet. All expansion joints should be caulked. All panels should be as square as possible. Saw cuts that are made should be made to a depth of at least 1/4 to 1/3 the thickness of the concrete slab (i.e. if the slab is 4 inches thick, the saw-cuts should be made to a depth of 1 to 1-1/3 inches in depth). Where concrete flatwork is adjacent to a.curb and/or a building slab, the flatwork should be doweled into the curb or foundation with 12-inch long No. 3 rebars on 36-inch centers. The dowels should be placed mid-height in the slab and be epoxied into the curb and allowed to cure prior to the placement of the concrete flatwork. 2) Exposure to Sulfate-Containing Solutions: The soluble sulfate content of the finish grade soils on the site is anticipated to be in the severe range based on 2006 California Building Code criteria. Comply with 2006 CBC criteria; and Maintain concrete water/cement ratio less than 0.5. 3) Drying Shrinkage Cracking: . Follow recommendations of AC! 302.1F for industrial/commercial structures, as appropriate; Maintain concrete water/cement ratio less than 0.5. Use minimum cement required to achieve desired strength; Design control joints; and Do not place concrete on hot, windy low-humidity. days. Concrete Flatwork Adjacent to Landscape Areas Typically, concrete flatwork located adjacent to landscape planters is subject to the effects of excessive moisture. To mitigate the lateral movement of landscape irrigation water, the use of a turn-down edge having a thickness of 15 inches and a width of 6 inches should be provided. The -4- Leighton 971009-051 turn-down edge should be poured monolithically with the concrete flatwork. If you have any questions regarding our letter, please contact this office. We appreciate this opportunity to be of service. {ESS6 D. II 2 I No. 4283 Respectfully submitted, LEIGHTON AND ASSOCIATES, INC. William D. Olson, RCE 45283 CO 0 Associate Engineer K. £ No. 1612 a.. CERTIFIED I/I n n 1 1 . ENGINEERING u Randall K. Wagner, G 1612 ''O/.CAL*° Principal Geologist Attachments:. Figure 1- Recommended Pavement Sections and R-Value Test Location Map Appendix A - References Appendix B - Laboratory Testing Procedures and Test Results Distribution: (2) Addressee (3) Grant General Contractor, Attention: Mr. John.Sandahi (3) City of Carlsbad Attention: Mr. Jay Jordon APPENDIX A References Carlsbad, City of, 2004, 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 June 2004. PDC, 2008, Plans for the Improvement of Bressi Ranch Village Center, Carlsbad, California, 14 Sheets, Drawing No. 452-9, dated February 7, 2008. Leighton and Associates, 2008a, Addendum Geotechnical Recommendations for Structural Foundations and Exterior Concrete Flatwork, Bressi Ranch Village Center, a Portion of Planning Area PA-15, Carlsbad, California, Project No. 971009-050, dated January 15, 2008. 2008b, Pavement Section Design Recommendations for the West Side of the Bressi Ranch Village Center, Carlsbad, California, Project No. 971009-050, dated March 28, 2008. 2008c, Pavement Section Design Recommendations for the East Side of the Bressi Ranch Village Center, Carlsbad, California, Project No. 971009-051, dated May 8, 2008. A-i 971009-051 APPENDIX B 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 Sample Location Sample Description R-Value Number R- I Driveway Adjacent to Pad "A" Yellow brown clayey SAND 32 R-2 Parking Area North of Major "C" Yellow brown clayey SAND 46 R3 Parking Area South of Shop "D" Olive brown silty lean CLAY 26 R4 Driveway Northeast Side of Major "A" Olive brown silty lean CLAY 24 R5 Parking Area South of Shop "F" Olive brown clayey SILT 39 R6 Parking Area Southeast of Shop "G" Pale brown clayey SILT with 53 sand R7 Driveway South of Shop "U" Gray silty SAND 60 R8 Parking Area Northwest of Major "A" Pale brown SILT with sand 51 R9 Main East-West Driveway Pale brown clayey SILT 34 (North of Shop "E") RIO Driveway West of Shop "F" Gray clayey SILT 29 Ri 1 Parking Area East of Pad "B" Dark gray silty lean CLAY 25 R12 Main East-West Driveway Yellow brown clayey SILT with 34 (North of Major "A") sand R13 Driveway South Side of Major "A" Pale yellow brown clayey SILT 51 R14 Driveway South of Shop "E" Yellow brown silty lean CLAY 22 R15 Driveway South of Major "B" Pale yellow brown lean CLAY 30 with sand R-16 Main East-West Driveway Gray silty SAND 57 "B") (South of Shop B-i COR FILE. Leighton and Associates, Inc. A LEIGHTON GROUP COMPANY March 28, 2008 Project No. 971009-051 To: LNR Property Corporation Commercial Property Group 4275 Executive Square, Suite 210 La Jolla, California 92037 Attention: Mr. Jeff Williams Subject: Pavement Section Design Recommendations for the West Side of the Bressi Ranch Village Center, Carlsbad, California References: Carlsbad, City of, L99' Standards for Design and Construction of Public Works Improvements in the City of Carlsbad, California, Project No. 05332-12-01, dated -A 64-2449~ ed-December-f ",96— PDC, 2008, Plans for the Improvement of Bressi Ranch Village center, Carlsbad, California, 14 Sheets, Drawing No. 452-9, dated February 7, 2008 Leighton and Associates, 2008, Addendum Geotechnical Recommendations for Structural Foundations and Exterior Concrete Flatwork, Bressi Ranch Village Center, a Portion of Planning Area PA-15, Carlsbad, California, Project No. 971009-050, dated January 15, 2008 Introduction In accordance with the requirements of the City of Carlsbad, this letter presents our pavement design recommendations for the proposed parking areas and driveways on the west side of the Bressi Ranch Village Center projectlocated in Carlsbad, California. In addition, this letter provides our addendum geotechnical recommendations concerning the concrete flatwork at the site. Two representative subgrade soil samples were obtained within the proposed driveways and parking areas. The samples were 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 ranging from 32 to 46. The approximate location of the samples is presented on the R-Value 3934 Murphy Canyon Road, Suite B205 • San Diego, CA 92123-4425 858.292.8030 • Fax 858.292.0771 -ii-P, \1 J - cc- (0 .0 .4 ü,0 .- oio C., Prior to placement of the aggregate base material, the upper 12 inches oubgrade soils (includin beneath the curb and gutter and 6-inches behind the curb and gutter)4aId be scarified, moisture- conditioned (or dried back) as necessary to at least a,2 percent over optimum moisture content and compacted to a minimum 95 percent relative compaction based on ASTM Test Method D1557. Table Recommended Pavement Sections Utilizing Class 2 Aggregate Base Class lass 2 Traffic Design Concrete Aggregate Location Index R-Value Thickness Base (inches) Thickness (inches) Parking Spaces 4.5 32 4.0 4.0 Auto Driveways 5.0 32 4.0 4.0 Truck Driveways 6.0 32 4.0 971009-051 Test Location Map attached as Figure 1, while the results of the laboratory testing are presented in Appendix A. We have assumed that the truck driveways have a Traffic Index (TI) of 6.0, the auto driveways have jTjof 5.0, and the parking spaces have a TI of 4.5. According to the city requirements (Carlsbad, the minimum pavement section for streets having a TI of 4.5 and 5.0 is 4 inches of Asphalt Concrete (AC) over 4 inches of Aggregate Base (AB) while the mirimum for streets having a TI of 6.0 is 4 inches of AC over 6 inches of AB regardless of the R-Valu 4A 4j 1CP Recommended Pavement Sections Utilizing Class 2 Aggregate Base Material Based on the above information, Class 2 Aggregate Base material 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. Class 2 Aggregate Bas+d then be placed and compacted at a minimum 95 percent relative compaction in accordance with ASTM Test Method D1557. It should be noted that our prior letter dated March 29, 2007 (Leighton, 2007), recommended that the curb an s be-placed directly on the subgrade soils without any base. The Class 2 Aggregate Base WNconform to and be placed in accordance with the latest revision of the California Department of Transportation -2- Leighton 971009-051 Standard Specifications (Section 26), the (3reenbook specifications, and/or the City of Carlsbad requirements. Asphalt Concrete ,lfil conform to and be placed in 'accordance with the "Greenbook" Standard Specifications for Public Works Construction and the City of Carlsbad requirements. 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 adyerse effects of water on the pavement subgrade. Elimination of the Aggregate Base Beneath On-Site Concrete Flatwork and Curbs/Gutters Based on our experience with similar soils in the vicinity of the site, it is our professional opinion that the on-site concrete flatwork and curbs/gutters (outside the City of Carlsbad easements) can be placed directly oii' the properly processed subgrade soils without any significant adverse affects. We have found that concrete flatwork founded directly on the subgrade soils (and'nidng with a turn-down edge) and curbs/gutters act as a barrier, which limits the migration of groundwater from storm water or landscape irrigation water and thereby reduces the possible- adverse effects of water on the pavement or subgrade soils. Therefore, we recommend that the on-site concrete flatwork curbs/gutters, be placed directly on properly processed subgrade soils. The 'subgrade soils beneath the on-site concrete flatwork should be placed as recommended in the following concrete flatwork section. Prior to the placement of the on-site curb/gutters, the upper 12 inches of the subgrade soils (including 6- inches behind the curb and gutter) should be' scarified, moisture-conditioned to at least 3 percent over the optimum moisture content and compacted to a minimum 95 percent relative compaction based on ASTM Test Method D1557.. Concrete' Flatwork Recommendations Due to the presence of medium (to possibly) highly expansive soils, the on-site concrete flatwork is subject to adverse conditions, such as, unsightly cracking, heaving, excessive water vapor transmission, and efflorescence. Adherence to the following guidelines will help mitigate potential adverse conditions. 1) Expansive Subgrade Soils: In order to reduce the potential heaving of the subgrade soils, we recommend that the upper 12 to 18 inches of the subgrade soils be scarified and 'moisture conditioned to at least 6 percent over the optimum moisture content. After the upper 12 to 18 inches of the subgrade soils has been moisture conditioned, the subgrade soils should be, recompacted to a relative compaction of between 85 to 88 percent. -3- Leighton 971009-051 The concrete flatwork should be at least 4 inches thick. Concrete flatwork outside the City of Carlsbad easements can be reinforced with 6x6/10-10 welded wire mesh. Expansion Joints and/or saw-cuts crack joints should be designed so that the concrete flatwork consists of square panels with a maximum dimension ranging from 4 to 5 feet All expansion joints should be caulked All panels should be as square as possible Saw cuts that are made should be made to a depth of at least 1/4 to 1/3 the thickness of the concrete slab (i.e. if the slab is 4 inches thick, the saw-cuts should be made to a depth of 1 to 1-1/3 inches in depth). Where concrete flatwork. is adjacent to acurb and/or a building slab, the flatwork should be doweled into the curb or foundation with 12-inch long No. 3 rebars on 36-inch centers. The dowels should be placed mid-height in the slab and be epoxied into the curb and allowed to cure prior to the placement of the concrete flatwork. 2) Exposure to 'Sulfate-Containing Solutions: The soluble, sulfate content of the finish grade soils on the site is anticipated to be in the severe range based on 2001 California Building Code criteria. Comply with 2001 CBC criteria; and Maintain. concrete water/cement ratio less than 0.5. 3) Ding Shrinkage Cracking: Follow recommendations of ACI 302.1F. for industrial/commercial structures, as appropriate; Maintain concrete water/cement ratio less than 0.5. Use minimum, cement required to achieve desired strength; Design control joints; and Do not place concrete on hot, windy low-humidity days. Concrete Flatwork Adjacent to Landscape Areas Typically, concrete flatwork' located adjacent to landscape planters is subject to the effects of excessive moisture. To mitigate 'the lateral movement of 'landscape irrigation water, the use of a turn-down edge having a thickness of 15 inches and a width of 6 inches should be provided. The turn-down edge should be poured monolithically with the concrete flatwork. -4- Leighton 971009-051 If you have any questions regarding our letter, plése contact. this office We appeciate this opportunity to 15e of service. . . Respeillysubmitted, LEIGHTON AND ASSOCIATES;•INC. William.D. Olson; RCE 45283 Associate Engineer Randall K. Wagner, CEG 1612 Principal Geologist óN A LQ . No. 1612 Figure .1 -R-Value :iest Location Map. Appendix A - Laboratory Testing.Proèdthes and Test Results PC DistributiOn: (2) Addressee (4) Grant General Contractor, Attention: Mr. John Sandahi 4. .5 ro ( 971009-051 APPENDIX A Laboratory Testina Procedures and Test Results "R"-Value: The resitänce 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-1 Driveway Adjacent to Pad "A" Yellow brown clayey SAND 32 R-2 Parking Area North of Major "C" Yellow brown clayey SAND 46 A-i Leiqhton