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HomeMy WebLinkAboutCT 04-15; LA COSTA GREENS NEIGHBORHOOD 1.07; PAVEMENT RECOMMENDATIONS 2005- 2006; 2006-06-20GEOCON APfOVED INCORPORATED GEOTECHNICAL CONSULTANTS cro1r, 0 RECEIVED CIT'i' OF CARI.SBAD ENGINEERING DEPARTMENT CM&I DIVISION Project No. 06403-52-24 June 20, 2006 K. Hovnanian companies of California 420 Stevens Avenue, Suite 170 Solana Beach, California 92075 Attention: Mr. Jim Norum Subject: VILLAGES OF. LA COSTA —THE GREENS NEIGHBORHOOD, 1.07 TITANITE PLACE - STATION 10+50 THROUGH 19+50 BROOKITE PLACE -STATION 10+00. THROUGH 14+,00 CARLSBAD;CALIFORNIA PAVEMENT RECOMMENDATIONS Gentlemen: In accordance with your request, we have performed supplemental geotechnical services for the subject roadways within the Villages of La Costa - The Greens development. The scope of our services included obtaining representative subgrade soil samples within the street areas and performing Resistance Value (R-Value) tests. The purpose of our work was to provide pavement design recommendations. To aid in preparing this letter, we have reviewed the improvement plans entitled Improvement & Utility Plans for. La Costa Greens - Neighborhood 1.07, prepared by Hunsaker and Associates, City of Carlsbad approval dated June 7, 2005 (Drawing No.427-6) and our report entitled Update Geotechnical Investigation, Villages' of La Costa - The Greens, Carlsbad, California, dated June 25, 2001 (Project No. 06403-12-03). Subgrade soils in the area are predominately sandy clays and silty sands and typically exhibit relatively low R-Value characteristics. Based on field observations along the subject alignments and previous laboratory tests at The Greens 'development, subgrade materials, possess an expansion potential of "low" to "medium" (Expansion Index of 90 or less) as defined by Uniform Building Code (IJBC) Table 18-I-B. R-Value laboratory tests were performed in accordance with ASTM D 2844-01 (California Test Method No. 301) and the laboratory test results are presented on Table I. Based on conversations with Hunsaker and Associates, the project civil engineer, we understand that a Traffic Index (TI) of 5.0 has been assigned to Titanite Place and Brookite Place. Based on the above information and laboratory testing, we recommend the pavement sections indicated on Table II. Pavement section calculations were performed in accordance with California Department of Transportation Highway Design Manual,' Section 608.4 and the City of Carlsbad Minimum Structural Standard GS-17. Pavement section calculations are, presented on Figure 1. These recommended sections should be considered preliminary with final sections to.be determined and approved by the City of Carlsbad. 6960 Flanders Drive 0 San Diego, California 92121-2974 0 Telephone (858) 558-6900 0 Fax (858) 558-6159 RCE 63291 SR:dmc As indicated on Table I, the R-Value laboratory test results for Sample Nos. R-3 and R6 were less than 12. It is our understanding that the City of Carlsbad requires testing for lime treatment of subgrade soils when the RValue is less* than 12. Our experience indicates that lime treatment is most effective when used in situations where clays of "high" expansion potential (Expansion Index of more than 90) are present. Due to the presence of silty sands and clays with "low" to "medium" expansion potential, it is our opinion, from a geotechnical standpoint, that the construction of a conventional pavement section along the subject alignment would be more appropriate. Based on the discussion above and recent conversations with City of Carlsbad staff, we understand that testing for lime treatment will not be required for the subject roadways. We are recommending the implementation of the conventional pavement section recommendations provided on Table II. Prior to placing base material for roadways as well as curb and gutter, we recommend the upper 12 inches of subgrade be scarified, moisture conditioned as necessary, and compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content in accordance with ASTM D 1557-02. In addition, the Class '2 aggregate base shall be compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content. Asphalt concrete shall be compacted to a density of at least 95 percent of the laboratory Hveem density ui accordance with ASTM D 2726-04. The upper 12 inches of subgrade beneath areas to receive concrete sidewalks shall be compacted to a dry density of 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content. Fill soil and aggregate base lift thicknesses should not exceed 6 inches. Class 2 aggregate base and asphalt concrete shall conform to the City of Carlsbad specifications. The performance of asphalt concrete pavement is highly dependent on providing positive surface drainage away from the edge of the pavement. The ponding of water on or adjacent to the pavement will likely result in pavement distress and subgrade failure. To reduce the occurrence for such situations, we recommend that a minimum drainage gradient of 1 percent be maintained for pavement surfaces. Drainage from landscaped areas should be directed to controlled drainage structures. Should you have any questions regarding this correspondence, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED (2) Addressee (1) Hunsaker and Associates Attention: Mr. David Blalock (3/del) K. Hovnanian Attention: Job Site Superintendent Proec1 No. 06403-52-24 - 2 - June 20, 2006 TABLE SUMMARY OF R-VALUE TEST RESULTS ASTM P 2844-01 (CALIFORNIA TEST METHOD NO. 301) Sample Number Location •• R-Value R-3 Titanite Place - Station 10+50 to 13+50 7 R-4 Titanite Place - Station 13+50 to 16+50 18 R-5 Titan ite Place - Station 16+50 to 19+50 15 R-6 Bro&Court 1 (L(V 1 A..I-flfl Q TABLE II PAVEMENT SECTION RECOMMENDATIONS Traffic Asphalt Concrete Class 2 Location Index (TI) (inches) Aggregate Base (inches) Titanite Place - Station 10+50 to 13+50 5.0 4.0 8.0 Titanite Place - Station 13+50 to 16±50 5.0 4.0 5.0 Titanite Place—Station 16+50 to 19+50 5.0 4.0 6.0 Brookite Coiftt— Station 10+00 to 14+00 5.0 4.0 7.0 JaJL.. - LlOI.tUII I V VU IV I 1 VU U Project No. 06403-52-24 June 20, 2006 FIGURE 1 PAVEMENT SECTION CALCULATIONS VILLAGES OF LA COSTA - THE GREENS Titanite Place - Stations 10+50 to 13+50 Use subgrade R-Value = 7.0 Traffic Index (TI) = 5.0 Methodology = Caltrans Highway Design Manual Section 608.4 Safety Factor = 0.2 - Applied to Asphalt Concrete (AC) GE for AC = (0.0032)(5.0)(100-78.0)+0.2 =.55 feet from Table 608.4 B Highway Design Manual GE = .55 feet for AC yields actual thickness = 2.65 inches' Use 4.0 inches of AC - City Minimum ' GE for 4.0 inches of AC = .83 feet GE for base = (0.0032)(5.0)(100- 7.0)- .83 = .65 feet from Table 608.4B Highway Design Manual, with GF for Class 2 base= 1.1 Base thickness = 7.14 inches - Use base thickness = 8.0 inches, per City of Carlsbad GS-17 Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 8.0 inches. Titanite Place - Stations 13+50 to 16+50 Use subgrade R-Value = 18.0 Traffic Index (TI) = 5.0 Methodology = Caltrans Highway Design Manual Section 608.4 Safety Factor = 0.2 - Applied to Asphalt Concrete (AC) GE for AC=(0.0032)(5.0)(I00-78.0)+0.2.55 feet from Table 608.4 B Highway Design Manual GE = .55 feet for AC yields actual thickness = 2.65 inches Use 4.0 inches of AC - City Minimum GE for 4.0 inches of AC = .83 feet GE for base =(0.0032)(5.0)(100-18.0)- .83 = .48 feet from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 5.22 inches Use base thickness = 5.0 inches Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 5.0 inches. Project No. 06403-52-24 June 20, 2006 FIGURE 1 (Continued) PAVEMENT SECTION CALCULATIONS VILLAGES OF LA COSTA - THE GREENS Titanite Place - Stations 16+50 to 19+50 Use subgrade R-Value = 15.0 Traffic Index (TI) = 5.0 Methodology = Caltrans Highway Design Manual Section 608.4 Safety Factor = 0.2 - Applied to Asphalt Concrete (AC), GE for AC = (0.0032)(5.0)(100-78.0)+0.2 = .55 feet from Table 608.413 Highway D'esign Manual GE = .55 feet for AC yields actual thickness = 2,65 inches Use 4.0 inches of AC - City Minimum GE for 4.0 inches of AC = .83 feet GE for base = (0.0032)(5.0)(100-15.0)- .83 = .53 feet from Table 608.413 Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 5.75 inches Use base thickness = 6.0 inches *** Design Street Structural Section *** Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 6.0 inches. Brookite Court - Stations 10+00 to 14+00 Use subgrade R-Value ='8.0 Traffic Index (TI) = 5.0 Methodology = Caltrans Highway Design Manual Section 608.4 Safety Factor = 0.2 - Applied to Asphalt Concrete (AC) GE for AC = (0.0032)(5.0)(I00-78.0)+0.2 = .55 feet from Table 608.413 Highway Design Manual GE = .55 feet for AC yields actual thickness = 2.65 inches Use 4.0 inches of AC - City Minimum GE for 4.0 inches of AC = .83 feet GE for base = (0.0032)(5.0)(100- 8.0)- .83 = .64 feet from Table 608.413 Highway Design Manual with GF for Class 2 base = 1.1 Base thickness= 6.97 inches Use base thickness = 7.0 inches *** Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 7.0 inches. Project No. 06403-52-24 June 20, 2006 APPROVED GEOCON INCORPORATED GEOTECHNICAL CONSULTANTS 0 Project No. 06403-52-24 June 2, 2006 K. Hovnanian Companies of California 420 Stevens Avenue, Suite 170 Solana Beach, California 92075 Attention: Mr. Jim Norum Subject: VILLGES OF LA COSTA - THE GREENS NEIORHOOD 1.07 GEODE LANE - STATIONS 10+00 THROUGH 17+00 CARLSBAD, CALIFORNIA PAVEMENT RECOMMENDATIONS Gentlemen: In accordance with your request, we have performed supplemental geotechnical services for the subject roadway within the Villages of La Costa - The Greens development. The scope of our services included obtaining representative subgrade soil samples within the street areas and performing Resistance Value (R-Value) tests. The purpose of our work was to provide pavement design recommendations. To aid in preparing Improvement & Utility Plans for: La Costa Greens -, Neighborhood 1.07, prepared by Huiisaker and Associates (Drawing No.427-6), City of Carlsbad .approval dated June 7, 2005 and our report entitled Update Geotechnical Investigation, Villages of La Costa - The Greens, Carlsbad, California, dated June 25, 2001 (Project No. 06403-12-03). Subgrade soils in the area are predominately sandy clays and silty sands and typically exhibit relatively low R-Value characteristics. Based on field observations at the subject alignment and previous laboratory tests atThe Greens development, subgrade materials possess an expansion potential of "low" tomedium" (Expansion Index of 90 or less) as defined by Uniform Building Code (UBC) Table 18-I-B. R-Value laboratory tests were performed in accordance with ASTM. D. 2844-01 (California Test MethodNo. 301) and the laboratory test results are presented on Table I. Based on conversations with Hunsaker and Associates, the project civil engineer, we understand that a Traffic Index (TI) of 5.0 has- been assigned to Geode Lane. Based on the above information and laboratory testing, we recommend the pavement sections indicated on Table II. Pavement section calculations were performed in accordance with California Department of Transportation Highway Design Manual; Section 608.4 and the City of Carlsbad Minimum Structural Standard GS-17. Pavement section calculations are presented on Figure 1. These recommended sections should be considered preliminary with final sections to be determined and approved by the City of Carlsbad. As indicated on Table I, the R-Value laboratory test results for Sample Nos. R-8 and R-9 were less than 12. It is our understanding that the City of Carlsbad requires testing for lime treatment of subgrade soils, when the R-Value is less than 12. Our experience indicates that lime treatment is most 6960 Flanders Drive •, San Diego, California 92121-2974 U Telephone (858) 558-6900 U Fax (858) 558.6159 effective when used in situations where clays of "high" expansion potential (Expansion Index of more than 90) are present. Due to the presence of silty sands and clays with "low" to "medium" expansion potential, it is our opinion, from a geotechnical standpoint, that the construction of a conventional pavement section along the subject alignment would be more appropriate. Based on the discussion above and recent conversations with City of Carlsbad staff, we understand that testing for lime treatment will not be required for the subject roadway. We are recommending the implementation of the conventional pavement section recommendations provided on Table II. Prior to placing base material for roadways as well as curb and gutter, we recommend the upper 12 inches of subgrade be scarified, moisture conditioned as necessary, and compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content in accordance with ASTM D 1557-02. In addition,, the Class 2 aggregate base shall be compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content. Asphalt concrete shall be compacted to a density of at least 95 percent of the laboratory Hveem density in accordance with ASTM D 2726-04. The upper 12 inches of subgrade beneath areas to receive concrete sidewalks shall be compacted to a dry density of 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content. Fill soil and aggregate base lift thicknesses should not exceed 6 inches. Class 2 aggregate base and asphalt concrete shall conform to the City of Carlsbad specifications. The performance of asphalt concrete pavement is highly dependent on providing positive surface drainage away from the edge of the pavement. The ponding ofwater on or adjacent to the pavement will likely result in pavement distress and subgrade failure. To reduce the occurrence for such situations, we recommend that a minimum drainage gradient of 1 percent be maintained for pavement surfaces. Drainage from landscaped areas should be directed to controlled drainage structures. Should you have any questions regarding this correspondence, or if we 'may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED oFESSi Nø.63291 Shane Rodacker Exp. 6130108 J, RCE 63291 SR:dmc 93 (2) Addressee (I) Hunsaker and Associates Attention: Mr. David Blalock (3/del) K. Hovnanian Job Site Superintendent Project No. 06403-52-24 -2- June 2, 2006 10 TABLE I SUMMARY OF R-VALUE TEST RESULTS ASTM D 2844-01 (CALIFORNIA TEST METHOD NO. 301) Sample Number Location R-Value R-8 Geode Way— Stations 10+00 to 13+00 9 R-9 Geode Way - Stations 13+00 to 17+00 10 I TABLE II PAVEMENT SECTION RECOMMENDATIONS • Location Traffic Index Class• 2 Asphalt Concrete Aggregate (TI) • (inches) • • Base (inches) Geode Way - Stations 10+00 to 13+00 5.0 4.0 7.0 Geode Way— Stations 13+00 to 17+00 5.0 4.0 7.0 FIGURE 1 PAVEMENT SECTION CALCULATIONS VILLAGES OF LA COSTA - THE GREENS Geode Way - Station 10+00 to 13+00 Use subgrade R-Valuç = 9.0 Traffic Index (TI) = 5.0 Methodology = Caltrans Highway Design Manual Section 608.4 Safety Factor = 0.2 - Applied to Asphalt Concrete (AC) GE for AC = (0.0032)(5.0)(100-78.0)+0.2 =.55 feet from Table 608.413 Highway Design Manual GE = .55 feet for AC yields actual thickness = 2.65 inches Use 4.0 inches of AC - City Minimum GE for 4.0 inches of AC = .83 feet GE for base = (0.0032)(5.0)(100- 9.0)- .83 = .62 feet from Table 608.413 Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 6.79 inches Use base thickness = 7.0 inches Design Street Structural Section I Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 7.0 inches. Geode Way - Station 13+00 to 17+00 Use subgrade R-Value = 10.0 Traffic Index (TI) =5.0 Methodology= Caltrans Highway Design Manual Section 608.4 Safety Factor = 0.2 -Applied to Asphalt Concrete (AC) GE for AC = (0.0032)(5.0)(100-78.0)+0.2 =.55 feet from Table 608 4B Highway Design Manual GE = .55 feet forAC yields actual thickness- 2.65 inches: I • Use 4.0 inches ofC - City Minimum GE for 4.0 inches of AC = .83 feet GE for base = (0.0032)(5.0)(100-10.0) -.83 = .61 feet from Table 608.413 Highway Design Manual with GF for Class 2 base 1.1 Base thickness = 6.62 inches Use base thickness = 7.0inches Design StreetStructural Section • Asphalt Concrete Thickness = 4.0 inches. • Class 2 Aggregate Base Thickness = 7.0 inches. Project No. 06403-52-24 • June 2, 2006 y• INCORPORATED Project No. 06403-52-21- December 8, 2005 GEOTECHNICAL CONSULTANTS - Real Estate Collateral Management Company % Morrow Development Incorporated 1903 Wright Place, Suite 180 Carlsbad, California 92008 . Attention: Mr. Tim O'Grady APPA Subject: VILLAGES OFOSTA - THE GREENS NEIGHBORO 4L2 : QUARTZ WAY - ST*PIONS 10+69 TO 12+39 CARLSBAD, CALIFORNIA PAVEMENT RECOMMENDATIONS Gentlemen: • In accordance with your request, we have performed supplemental geotechnical services for the subject roadway within the Villages of La Costa - The Greens development. The scope bf our services included obtaining representative subgrade soil samples within the street area and performing Resistance Value (R-Value) tests. The purpose of our work was to provide pavement gri To aid in preparing this letter, we have reviewed the improvement plans entitledIrnproi)emeñt Plans and Utility Plans for. La Costa Greens Neighborhood 1.07 Backbone, prepared by Hunsaker andAssociates (Drawing No. 427-613), City of Carlsbad approval dated June 7, 2005, and our report entitled Update Geotechnical Investigation, Villages of La Costa .- The Greens, Càrlsbad, California, dated June 25, 2001 (Project No. 06403-12-03). Subgrade soils in the area are predominately sandy clays and silty sand, and typically exhibit relatively low R-Value characteristics. Based on field • observations and previous- laboratory tests, subgrade materials possess an expansion potential S l) as defined by Uniform Building Code (UBC) Table 187I-B. RVálue laboratory tests were performed in accordance with ASTM D 2844-01 (California Test Method No. 301) and the laboratory test results are presented on Table I. Based on conversations with Hunsaker and Associates, the project civil engineer, we understand that been assigned to the Quaitz Way. Baked on the above infomation and laboratory testing, we recommend the pavement sections indicated on Table- II. Pavement section calculations were perfdrmed in accordance with California Department Iof Transportation Highway Design Manual Section 608 4 and the City. of Carlsbad Minimum Structural Standard GS-17 Pavement section calculations are presented on Figure 1 As indicated on Table 1, the R-Value laboratory test result for Sariple No. R-'8. was less than 12. It is our understanding that the City of Carlsbad requires testing for lirnetreatment of subgrade soils when the R-Valiie is less'than .•, . 6960 Flanders-Drive • Son Diego, California 92121-2974 • Telephone (858) 558-6900"i Fax (858) 558.6159 S., • - .5 5• -.---------- --•• -••- '•5 - --• .---- ciiitiiãtions where clays of high' expansion potential (Expansion Index of more than 90) are (present.)Due to the presence of silty sands and clays with "low" to "medium" expansion potential, it is our opinion, from a geotechnical standpoint, that the construction of a conventional pavement section along the subject alignment would be more appropriate. Based on the discussion above and recent conversations with City of Carlsbad staff, we understand that testing for lime treatment will not be required for the subject roadway yeiiãre recommending the implementation of the cconventional pavement section recommendations provided on Table II Prior to placing base material for roadways as well as curb and gutter, we recommend the upper 12 inches of subgrade be scarified, moisture conditioned as necessary, and compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content in accordance with ASTM D 1557-02. In addition, the Class 2 aggregate base shall be compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content. Asphalt concrete shall be compacted to a density of at least 95 percent of the laboratory Hveem density in accordance with ASTM D 2726-04. The upper 12 inches of subgrade beneath areas to receive concrete sidewalks shall be compacted to a dry density of 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content. Fill soil and aggregate base lift thicknesses should not exceed 6 inches. Class 2 aggregate base and asphalt concrete shall conform to the City of Carlsbad specifications. The performance of asphalt concrete pavement is highly dependent on providing positive surface drainage away from the edge of the pavement. Ponding of water on or adjacent to the pavement will likely result in pavement distress and subgrade failure. To reduce the occurrence for such situations, we recommend that a minimum drainage gradient of 1 percent be maintained for pavement surfaces. Drainage from landscaped areas should be directed to controlled drainage structures. Should you have any questions regarding this correspondence, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED OFEs Shane Rodacker coNo. 63291 RCE 63291 CC EXP. 6/30106 rn SR:dmc AAL UPCALI (2) Addressee (3/del) Morrow Development, La Costa Greens Jobsite Attention: Mr. Mike Lombardi (1) Hunsaker and Associates Attention: Mr. David Blalock Project No. 06403-52-21 - 2 - - - December 8, 2005 TABLE I SUMMARY OF R-VALUE TEST RESULTS ASTM D 2844-01 (CALIFORNIA TEST METHOD NO. 301) Sample Number Location Value R-1 Quartz Way— Stations 10+69 to 12+39 TABLE II PAVEMENT SECTION RECOMMENDATIONS Location Traffic Index Asphalt Concrete Class 2 Aggregate Base - (TI) (inches) (inches) Quartz Way 50 40 Stations 10+69 to 12+39 I S Project No. 06403-52-21 . December 8, 2005 / FIGURE 1 PAVEMENT SECTION CALCULATIONS VILLAGES OF LA COSTA - THE GREENS Quartz Way - Stations 10+69 to 12+39 Use subgrade R-Value = 5.0 Traffic Index (TI) = 5.0 Methodology = Caltrans Highway Design Manual Section 608.4 Safety Factor = 0.2 - Applied to Asphalt Concrete (AC) GE for Ac = (0.0032)(5.0)(100-78.0)+0.2 =.55 feet from Table 608.413 Highway Design Manual GE = .55 feet for AC yields actual thickness = 2.65 inches ' Use 4.0 inches of AC - City Minimum GE for 4.0 inches of AC = .83 feet GE for base = (0.0032)(5.0)(100-5.0) -.83 = .69 feet S from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 7.49 inches Use base thickness = 9.0 inches (pefptevious recommendation of City of Carlsbad),-, - . 4 *** Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. - Class 2 Aggregate Base Thickness = 9.0 inches. Pràject No. 06403-52-21 December 8, 2005 :GEOCON INCORPORATED - Proje& No.. 0640352-21 November 21, 2005 • GEOTECHNICAL CONSULTANTS tJJ\ 'ADP Real Estate Collateral Management Company % Morrow Development Incorporated 1903 Wright Place;'Suite 180 Carlsbad, California 92008 Attention: Mr. Tim O'Grady Subject: VILLAGES OF LA COSTA - THE GREENS NEIGHBORHOOD 1.07 MICKROADSTATIONS 2450THRDUGHT4057 CARLSBAD; CALIFORNIA - PAVEMENT RECOMMENDATIONS Gentlemen: In adoEdance with your request, we have performed supplemental geotechnical services for the subject roadway within the Villages of La Costa - The Greens development. The scope of our services included obtaining representative subgrade soil samples within the street area and performing Resistance Value (R-Value) tests.. The purpose of our work was to provide pavement design recommendations. To aid in preparing this letter, we have reviewed the improvement plans entitled Improveiient Plans and Utility Plans for: La Costa Greens - Neighborhood 1.07 Backbone, prepared by Hunsaker and Associates (Drawing No. 427-613), City of Carlsbad approval dated June 7, 2005, and our report entitled Update Geotechnical Investigation, Villages of La Costa - The Greens, Carlsbad, California, dated June, 25 2001 (Project No. 06403-12-03). Lel ubgdiiterials possess an expansionpotentia1-of--low-'- to—medium— (Expansion 4ndex Thf906i less) eas defined by Uniform Building Code (UBC) Table 18-I-B. R-Value laboratory tests were performed in accordance with ASTM D 2844-01 (California Test Method No. 301) and the laboratory test results are presented on Table I. Bid on con versiiions withHsakerandrAssoiatë' - U U _ - . - - . - Based on the above information and laboratory testing, we recommend the pavement sections indicated on Table H. Pavement section calculations were performed in accordance with California Department of Transportation Highway Design Manual; Setion 608.4 and the City of Carlsbad Minimum Structural Standard Usz fn Pavement -section. calculations are presented on Figure.l. These recommended sections should be considered preliminary with final sections to be determinedand approved by the City of Carlsbad. • for-Sample wëifless -than 4-2. It is our understanding that the City of Carlsbad requires testing for lime treatment of subgrade soils when theI R-Value is less than 12Qir:experienceindicates that lunetieatment tis most effective when ed in situations wheTëlãf hih.xpinsion potential (ExpansioifhTdex of ffirethan.90)are:present Due to the presence of silty sands and clays with "low" to 'medium 6960 Flanders Drive 0 San Diego, California 92121-2974 • Telephone (858) 558-6900 U Fax (858) 558.6159 11 expansion potential conventionalpavementsection.along.the_subject alignment .would be more_appropnateBasedonthE above _withCit5iöf CaiElii staff we_understandthattetifirf& roàd7_. We1 arerecommendingthe. _______ -. i• - - - - - timplemeñtatiöiT6f the conventional pavement section recommendations provided on Table 11' 'Pñor_to placi benaterialfor roadwaysas:we1la rrbandiitter I2inchs moisture ncI1iid•as f-t last5Icii of- tlila imimddëiisity near to slightly above optimumThiö1 tiiië) !Ejt_m.ac(TrdancewithASTM_D 1557.02)In addition"the Class 2 aggregate base shall be compacted to a 4dry density of at least 95prcent of the lboratorymaximum dry density near to slightly above optimum moisture content compacted-to adensityof atleat95percent of the1aboratTHeem Vdenity--in accordanceithASTMD 2726-04 The pper 12 inches of subgrade beneath areas to receive corcret&'sidewá1ks shallb onpá'cted to a dry disity ?f 90 percent of the laboratory maximum dry density near to slightly, above optimum moisture content Fill soil and aggregate base lift thicknesses should not exceed 6 ichesClass -2 aggregate base and asphalt concrete shaff cohforrn to the City of Carlsbad specifications - -. - -, - The performance of asphalt concrete pavement is highly dependent on providing positive surface drainage away, rom the edge of the pavement Ponding of water, on or adjacent to the pavement will likely result in pavement distress and subgrade failure" To reduce the occurrence for such situations we recommend that a minimum drainage gradient of 1 percent be maintained for pavement surfaces Drainage from landscaped areas should be directed to controlled drainage structures Should you have any questions regarding this correspoildence or if we may be of further service please contact the undersigned at your convenience -. - Very truly yours, I "V -.•• - -. ._..i-.,.. V. GEOcONTCPpTD; V 63291 Exp. 6/30/06 rn Michael C. Ertwirie Shan Rodaêker - - -' Senioi Staff Geolgist RCE 63291 OF C (2) Addrese" (3/del) Morow-Deve1oprnerit; La Costa Gieens Jobsite, I - Attention Mr Mike Lombardi (1) - Hunsaker and Associates Attention: Mr. David Blalock V • • V / •' - V V V V• - 'V Projeàt No. 06403-52-21 V V - 2 - - •V V V November 21, 2005 TABLE I SUMMARY OF R-VALUE TEST RESULTS ASTM D 2844-01. (CALIFORNIA TEST METHOD NO. 301) Sample Number Location R-Value R-1 . Mica Road - Stations 24+50 to 27+00 11 R-2 Mica Road - Stations 27+00 to 29+50 . 25 R3 Mica Road - Stations 29+50 to 32+00 14 R-4 . Mica Road - Stations 32-00 to 34+50 9 R-5 Mica Road - Stations 34+50 to 37+00 7 R-6 Mica Road— Stations 37+00 to 38+75 7 R-7 . Mica Road - Stations 38+75 to 40+57 . 5 TABLE Ii PAVEMENT SECTION RECOMMENDATIONS Location Traffic Index Asphalt Concrete Class 2 Aggregate Base (Ti) (inches) (inches) Mica Road 5.0 4.0 7.0 Stations 24+50 to 27+00 Mica Road 5.0 4.0 Stations 27+00 to 29+50 Mica Road 5.0 4.0 - 6.0 Stations 29+50 to 32+00 Mica Road 5.0 4.0 . 7.0 Stations 32+00 to 34+50 Mica Road 5.0 4.0 8.0 Stations 34+50 to 38+75 - Mica Road 5.0 4.0 9.0 Stations 38+75 to 40+57 / Project No 06403-52-21 . November 21, 2005 FIGURE 1 PAVEMENT SECTION CALCULATIONS VILLAGES OF LA COSTA-THE GREENS Mica Road - Stations 24+50 to 27+00 Use subgrade R-Value = 11.0 -. Traffic Index (TI) = 5.0 ' Methodology = CALTRANS Highway Design Manual Section 608.4 Safety Factor = 0.2 -- Applied to Asphalt Concrete (AC) GE for AC = (0.0032)( 5.0)(100-78.0)+0.2 = .55 feet from Table 608.4B Highway Design Manual 'GE = .55 feet for AC yields actual thickness = 2.65 inches ' Use 4.0 inches of AC - City Minimum GE for 4.0 inches of AC = .83 feet GB for base = (0.0032)( 5.0)(100-11.0) - .83 = .59 feet from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 6.44 inches Use base thickness = 7.0 inches - I Design Street Structural Section *** Asphalt Concrete Thickness = .4.0 inches. S Class 2 Aggregate Base Thickness = 7.0 inches. Mica Road - Stations 27+00 to 29+50 Use subgrade R-Value = 25.0 Traffic Index (TI) = 5.0 ' Methodology = CALTRANS Highway Design Manual Section 608.4 Safety Factor = 0.2 -- Applied to Asphalt Concrete (AC) GE for AC = (0.0032)( 5.0)(100-78.0)+0.2 = .55 feet from Table 608.4B Highway Design Manual GE = .55 feet for AC yields actual thickness = 2.65 inches Use 4.0 inches of AC - City Minimum GE for-4.0 inches of AC = .83 feet GE for base = (0.0032)( 5.0)(100-25.0) - .83 = .37 feet from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 400 inches " Use base thickness = 4.0 inches Design Street Structural Seëtion Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 4.0 inches. Project No. 06403-52-21 S November 21, 2005 FIGURE 1 (Continued) PAVEMENT SECTION CALCULATIONS VILLAGES OF LA COSTA - THE GREENS Mica Road - Stations 29+50 to 32+00 Use subgrade R-Value = 14.0 Traffic Index (TI) = 5.0 " Methodology = CALTRANS Highway Design Manual Section 608.4 Safety Factor = 0.2 -- Applied to Asphalt Concrete (AC) GE for AC = (0.0032)( 5.0)(100-78.0)+0.2 = .55 feet from Table 608.4B Highway Design Manual GE = .55 feet for AC yields actual thickness 2.65 inches Use 4.0 inches of AC - City Minimum GE for 4.0 inches of AC = .83 feet GE for base = (0.0032)( 5.0)(100-14.0) - .83 = .54 feet from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = EDnches Use base thickness = 6.0 inches *** Design Street Structural Section *** / Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 6.0 inches. Mica Road - Stations 32+00 to 34+50 Use subgrade R-Value =.9.0 Traffic Index (Ti) = 5.0 Methodology = CALTRANS Highway Design Manual Section 608.4 Safety Factor = 0.2 -- Applied to Asphalt Concrete (AC) GE for AC = (0.0032)( 5.0)(100-78.0)+0.2= .55 feet from Table 608.4B Highway Design Manual GE = .55 feet for AC yields actual thickness = 2.65 inches Use 4.0 inches of AC - City Minimum GE for 4.0 inches of AC = .83 feet GE for base = (0.0032)( 5.0)(100- 9.0) - .83 = .62 feet from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 6.79 inches" I Use base thickness = .7.0 inches *** Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 7.0 inches. Project No. 06403-52-21 November 21, 2005 FIGURE 1 (Continued) PAVEMENT SECTION CALCULATIONS VILLAGES OF LA COSTA - THE GREENS Mica Road - Stations 34+50 to 37+00 Use subgrade R-Value = 7.0 Traffic Index (TI) = 5.0 Methodology = CALTRANS Highway 'Design Manual Section 608.4 Safety Factor = 0.2 -- Applied to Asphalt Concrete (AC) GE for AC = (0.0032)( 5.0)(100-78.0)+0.2 = .55 feet from Table 608.4B Highway Design Manual GE = .55 feet for AC yields actual thickness = 2.65 inches Use 4.0 inches of AC - City Minimum GE for 4.0 inches of AC = .83 feet GE for base = (0.0032)( 5.0)(100- 7.0) - .83 = .65 feet from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 7.14 inches Use base thickness = 8.0 inches *** Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 8.0'inches. Mica Road - Stations 37+00 to 38+75 Use subgrade R-Value = 7.0 Traffic Index (TI) = 5.0 Methodology = CALTRANS Highway Design Manual Section 608.4 Safety Factor = 0.2 -- Applied to Asphalt Concrete (AC) GE for AC = (0.0032)( 5.0)(100-78.0)i-0.2 = .55 feet from Table 608.413 Highway Design Manual GE = .55 feet for AC yields actual thickness = 2.65 inches Use 4.0 inches of AC - City Minimum GE for 4.0 inches of AC = .83 feet GE for base = (0.0032)( 5.0)(100- 7.0) - .83 = .65 feet from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 7.14 inches / Use base thickness = 8.0 inches -V Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. v Class 2 Aggregate Base Thickness = 8.0 inches. Project No. 06403-52-21 ' ' November 21, 2005 Project No. 06403-52-21 H FIGURE 1 (Continued) PAVEMENT SECTION CALCULATIONS VILLAGES OF LA COSTA - THE GREENS Mica Road - Stations 38+75 to 40+57 Use subgrade,R-Valüe 5.0 Traffic Index (TI) = 5.0 Methodology = CALTRANS Highway Design Manual Section 608.4 Safety Factor = 0.2 -- Applied to Asphalt Concrete (AC) GE for AC = (0.0032)( 5.0)(100-78.0)+0.2 = '.55 feet from Table 608 4B Highway Design Manual GE = .55 feet for AC yields' actual thickness = 2.65 inches Use 4.0 inches of AC -City Minimum GE for 4.0 inches of AC = .83 feet GE for base = (0.0032)( 5.0)(100- 5.0) - .83 = .69 feet from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness'= 7.49 inches" Use base thickness = 9.0 inches (per previous recommendation of City of Carlsbad) *** Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 9.0, inches.