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Home My WebLink AboutCT 02-22; LA COSTA GREENS NEIGHBORHOOD 1.09; PAVEMENT SECTION RECOMMENDATIONS 2004; 2004-10-13CT 0 GEOCON :. INCORPORATED - -.. GEOTECHNICAL CONSULTANTS( 410>) Project No. 06403-52-13 October 13, 2004 - 0 to/zoIo D. R. Horton, Western Pacific Housing Series oUQA.o.' 5790 Fleet Street, Suite 210 : Carlsbad, California 92009 Attention: Mr. Kurt Baüsback Subject: VILLAGES OF LA COSTA - THE GREENS NEIGHBORHOOD 1.09 LAPIS ROAD NORTH STATION 16+00 TO 26+00 CARLSBAD, CALIFORNIA PAVEMENT SECTION RECOMMENDATIONS Gentlemen: ' In accordance with your request, we have performed supplemental geotechnical services for the subject alignment within 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 Plans for: La Costa Greens - Neighborhood 1.09, prepared by Hunsaker and Associates (Drawing No. 406-7),. City of Carlsbad approval dated May 6, 2004, and our report - entitled Final Report of Testing and Observation Services Performed During Site Grading, Villages of La Costa The Greens, Neighborhood 1.09, Carlsbad, California, dated June 21, 2004 (Project No 0640 3-52-09).' Subrade soils in the area are predominately sandy clays and silty sands, and typically .exhibit relatively low R-Value characteristics Basedon'field observations and previous laboratory tests, subgrade mat&rials possess an expatisiôn 151entiâl of "lOw" to "medium" (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 -Method No. 301) and the laboratory test results are presented on Table I. 0 - Based on conversations with Hunsaker and Associates, the project civil engineer, we understand that has been assigned to the subject alignment. Based on the above information and laboratory testing, werecommefid1the pavementëti iiridicàtedon Taé ll bl Pavement &i seãti calculations -were perfo diñãiidãice with California Depat) of Transportation Highw DijMthiidl; Section 608.4 and 0 the City of Carlsbád Minimum Structural Standard GS-1 7 Pavement section calculations are presented on Figure 1 Were the pavement, section, recommendations provided on TablH Fhese recommended sètiö shöü1d bediiidë ëliñuffãivith fmal sectiôf bdtñiid 6960 Flanders Drive • 0 Son Diego, California 92121-2974 • Telephone (858) 558-6900 • Fax (858) 558-6159 0 0 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 should 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 should be compacted to a density of at least 95 percent of the laboratory Hveem density in accordance with ASTM D 2726-00. The upper 12 inches of subgrade beneath areas to receive concrete sidewalks should 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 base lift thickness should not exceed 6 inches. Class 2 aggregate base and asphalt concrete should conform to the City of Carlsbad specifications. The performance of asphalt concrete pavement is highly depehdent on providing positive surface drainage away from the edgeof the pavement. Ponding of water on or adjacent to the pavement will likely result in pavement distress and subgrade failure. Ta reduce the occurrence for such situations, we recommend that a minimum drainage gradient of 1 percent be maintained for pavement surfaces. Drainage form 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 ( No. 63291 Michael C. Ertwine Shane Rodacker U.1 Exp. &3OJ Staff Geologist RCE 63291 * CIV 1. MCE:SR:anh 'OFCAU (2) ' Addressee' (3/del) D. R. Horton, Western Pacific Housing Series; La Costa Greens Jobsite Attention: Mr. Corey Miller (1) ' Hunsaker and Associates ' Attention: Mr. David Blalock Project No. 06403-52-13 ' ' - 2 - October 13, 2004 TABLE I SUMMARY OF LABORATORY R--VALUE TEST RESULTS ASTM D 2844-01 (CALIFORNIA TEST METHOD NO. 301) Sample No. Location . . RValue R-8 Lapis Road North Station 16+00 to 18+50 22 R-9 Lapis Road North Station 18+50 to 21+50 .15 R-10 Lapis Road North Station 21+50 to 23+50 25 R-11 Lapis Road North Station 23+50 to 26+00 .15 TABLE II PAVEMENT SECTION RECOMMENDATIONS Location . Traffic Index (TI) Asphalt Concrete (inches) Class 2 Aggregate Based : (inches) Lapis Road North Station 16+00 to 18+5.0 5.0 4 - Lapis Road North Station 18+50 to 21+50.. . 50 4 6 Lapis Road North Station 21+50 to 23+50 - 50 • 4 . . Lapis Road North Station 23+50 to 26+00 5.0 . 4 . - 6 . O?%.?er ofc... • *tr 0S44 FIGURE 1 PAVEMENT SECTION CALCULATIONS VILLAGES OF LA'COSTA - THE GREENS Lapis Road - Station 16+00 to 18+50 Use subgrade R-Value = 22.0 Traffic Index (TI)=5.0 S 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 S Use 4.0 inches of AC - City Minimum GE for4.9 inches of AC = .83 feet GE for base =(0.0032)(5.0)(100-22.0) - .83 = .41 feet from Table 608.4B Highway Design Manual with GF for Class 2 base- 1.1 Base thickness = 4.52 inches Use base thickness = 5.0 inches Design. Street Structural Section *** Asphalt Concrete Thickiiess = 4.0 inches. Class 2 Aggregate Base Thickness = 5.0 inches. Lapis Road - Station 18+50 to 21+50 Use subgrade R-Value = 15.0 Traffic Index (TI)=5.0 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= (O.0032)(5.0)(100-15.0)- .83=...53-feet . from Table 608 4B Highway Design Manual with GF for Class 2 base 11 Base thickness = 5.75 inches Use base thickness = 6.0 inches *** Design Street Structural Section 5 5 Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness =6.0 inches. . S Project No. 06403-52-13 5 5 October 13,2004 5 FIGURE 1 (Continued) PAVEMENT SECTION CALCULATIONS VILLAGES OF, LA COSTA -THE GREENS Lapis Road Station 21+50 to 23+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 = 11 Base thickness = 4.00 inches Use base thickness = 4.0 inches Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. ' Class 2 Aggregate Base Thickness = 4.0 inches. r Lapis Road - Station 23+50 to 26±00 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 608.4B 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)(10-115.0) - 83 = 53 feet from Table 608.4B 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 Project No. 06403-52-13 October 13, 2004 &(O24/1/ GEOCON INCORPORATED Project No. 06403-52-13 September 27, 2004 GEOTECHNICAL CONSULTANTS (ow/ '4 Aee 1- D. R. Horton, Western Pacific Housing Series 5790 Fleet Street, Suite 210 Carlsbad, California 92009 Attention: Mr. Kurt Bausback Subject: VILLAGES OF LA COSTA - THE GREENS NEIGHBORHOOD 1.09 JADE LANE STATION 21+00 TO 27+00 KORITE PLACE STATION 10+00 TO 13+15 -. LARIMAR AVENUE STATION 14+00 TO 21+00 LUECITE PLACE STATION 10+00 TO 14+00 CARLSBAD, CALIFORNIA PAVEMENT SECTION RECOMMENDATIONS Gentlemen: In accordance with your request, we have performed supplemental geotechnical services for the subject roadway alignments within 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 Plans for: La Costa Greens - Neighborhood 1. 09, prepared by Hunsaker and Associates (Drawing No. 406-7), City of Carlsbad approval dated May 6, 2004, and our report entitled Final Report of Testing and Observation Services Performed During Site Grading, Villages of La Costa-The Greens, Neighborhood 1.09, Carlsbad, California, dated June 21, 2004 (Project No. 06403-52-09). Subgrade soils in the area are predominately sandy clays and silty sand, and typically exhibit relatively low to medium R-Value characteristics. Based on field observations and previous laboratory tests, subgrade materials possess an expansion potential of "low" to "medium" (Expansion Index of 90 or less) as defined by Uniform Building Code (I BC) 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!1raffic Index(.TI) of5.0 has been assigned to the subject roadway alignments. Based on the above information and laboratory testing, we recommend the pavement sections indicated on Table II. 6960 Flanders Drive • San Diego, California 92121-2974 0 Telephone (858) 558-6900 0 Fax (858) 558-6159 - - :- iE• - --- . : '---- -•-' - .; '- -'-' tr - - - -, -_-- - -' .-, .., -, ., Pavement section calculations were performed in accordance with CalfOrnia Department of Transportation Highway Design Manual, Section 608.4 and the City: of Carlsbad Minimum Structural Standard 'GS-1 7 Pavement section calculations are presented on Figure 1 These recommend&l 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 No. R-1- was 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. Therefore, additional laboratory testing. was erformed on Sample No. R-1 to assess the actual amount of lime requirecLto effectively treat the subgrade soils. OJ The laboratory lime testing was based on the Texas Method;-which-cönsistsofperforming a series of 1-' .$ Plasticity Index (P1) tests atdifferent lime contents until the PPstabilizesTable-fflshows the result of th& PT tests versuslime content. -It is our opinion that 3.5 per QuiclLimby dry weight (or 4.5 percent hydrated lime) is required to stabilize clayey subgrad SujImental R-Value testing of the lime treated materials shows thattheRValue1 increased. t69 ,Table IV provides an alternative recommendedpàvement se&ioi tht ifcoporâte's a limtreätèd sibgrade. The minimum thickness of lime-treated subgrade is estimated to be 6 inches. Prior to plaèing- 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 11 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 2agregate base should be compacted. to a dry density of at least 95 percent of the laboratory maxirfiiin dry density near to slightly: above optimum moisture content. -..- Asphalt áoncreteshoüld be compacted to a density of at least 95.:percent of- .the laboratory Hveem density in accordance with ASTM D 2726-00 The upper 12 inches of subgrade beneath areas to receive concrete sidewalks should be compacted to a dry density of 90 percent of the laboratory maximum diy density near to slightly above optimum moisture content. Fill soil and base lift thickness should not exceed 6 inches. Class 2 aggregate base and asphalt cdricrete. should 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 occurrenc for such situations we recommend that- a minimum drainage gradient of 1 percent'be maintained,, for. pavement surfaces. Drainage form landscaped areas should be directed to controlled drainage sthturés.. - - - Project No. 06403-52-13 - 2 - - September 27 .2004 - '.' Should you have any questions regarding this correspondence, or if we nay be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED " Michael CErtwine e dacke No. Staff Geologist RCE 63291 CO M rm ZO Exp. MCE i::ssee (3/del) D. R. Horton, Western Pacific Housing Series .. . La CostàGfeeis, Job Site S. Attëntithi: Mr'. Corey Miller (1) Hinsaker and Associates Attention Mr David Blalock 'I Project No. O643-5243 -3- ' September 27, 2004 TABLE SUMMARY OF LABORATORY R-VALUE TEST RESULTS ASTM D 2844-01 (CALIFORNIATEST METHOD NO. 301) Sample No. Location R-Value R-1 .Jade Lane Station 24+00 to 27+00 6 R-2 Jade Lane Station 21+00 to 24+00 39 R-3 Larimar Avenue Station 17+50 to 21+00 24 R4 Larimar Avenue Station 14+00 to 17+50 22 R-5 Korite Place Station 10+00 to 13+15 13 R-6 Luecite Place Station 12+00 to 14+00 35: R-7 Luecite Place Station 10+00 to 12+00 16 TABLE II PAVEMENT SECTION RECOMMENDATIONS - CONVENTIONAL Location TrafficIndex. . (TI) ASphaltCdncrètè (inches) . ., - Class Aggregate Base (inches) Jade Lane Station 24+00 to 27+00 5 0 4 8 Jade Lane Station 21+00 to 24+00 5.0 .4 6. *401 Larimar Avenue Station 17+50 to 21+00 5.0 .4 '. 5 V Larimar Avenue Station 14+00 to 17+50 5.0 4 5 / Korite Place Station 10+00 to 13+15 . 5.0 4 . . Luecite Place Station 12+00 to 14+00 5.0 4 .fr Luecite Place Station 10+00 to 12+00 5.0 4 . . S TABLE III SUMMARY OF LABORATORY PLASTICITY INDEX VS. LIME CONTENT SAMPLE NO.., R-1 - JADE LANE STATIONS 24+00 TO 27+00 Plasticity Index (P1) . PercentLime 33 .0°. 23. 3 23 . 4 22 5 19 6 I / J / / / /5 Project No. 06403-52-13 . S . September 27, 2004 TABLE IV .' ALTERNAVE PAVEMENT SECTION REC9MIENDATION.S. tMc Asp aIt Cass2 ' MinimuinLime- Location I>hidel>< Concrete Aggregate Base Treated Subgrade 4nches) (inches).: . (inches) Jade Lane Sta'ti'on 24+00 to 27+0Q, '5.0 . 6 FIGURE 1 PAVEMENT SECTION CALCULATIONS. VILLAGES OF LA COSTA - THE GREENS Jade Lane - Station 24+00 to 27+00 Use subgradeR-Valüe = 6.0 Traffic Index (TI) = 5.0 - Methodology = Caltrans Highway Design Manual Section 608.4 Safety Factor = 0.2 - Applied to Asphalt COncrete (AC) GE forAC = (0.0032)( 5.0)(100778.0)+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-.6.0) -.83 =.67 feet from Table 608.4B Highway Design Manual with GF for Class 2 base=.1. I Base thicknes = 7:32 inches Use base thickness = 8.0 inches Design Street Structural Section Asphalt Concrete, Thickness = 4.0inches. Class 2 Aggregate Base Thickness =8.0. inches. Jade Lane.— Station 21+00 to 24+00 Use subgrade R-Value = 39.0 Traffic Index (TI) =5.0 Methodology = Caltrans Highway Design ManualSection 608.4 Safety Factor= 0:2 Applied tO Asphalt Coucrete(AC) . . GE for AC = (0.0032)( 5.0)(l00-78.0)+0.2'-=:55 feet from Table 608 4B Highway Design Manual GE = .55 feet for AC yields àctüal thickness = 2.65 inèhes Use .4.0 inches of AC - City Minimum GE for 4.0 inches of AC = .83 feet GE for base (0.0032)( 5.0)(100-39.0) - .83.= .14 feet . fromTable 608.4B Highway Design Manual with GF for Class 2 base = 1:1 Base thickness= 1.56 inches " Use base thickness = 4.0 inches, City Minimum Design Street Structural Section Asphalt Concrete Thickness = 4 0 inches Class 2 Aggregate Base Thickness = 4.0. inches. Project No. 06403-5243 . . . September 27; 2004 FIGURE 1 (Continued) PAVEMENT SECTION CALCULATIONS VILLAGES OF LA COSTA - THE-GREENS, Larimar Avenue - Station 17+50 to. 21+00 Use subgrde R-Value.= 24.0 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)(100-24.0) - .83 = .38 feet from Table- 608.'4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 4.17 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. " Larimar Place Station 14+00 to 17+50 Use subgrade.R-Value = 22.0 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)(100778.0)+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 40 inches of AC .83 feet . GE for base =,(0.0032)( 5.0)('100-2'2.0) -.83 =.41 feet from Table 608.4BiHighwày Design Manual 'With GF for Class 2 base = 1.1 Base thickness = 4.52 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. 06403-52-13 September 27, 2004 KoritePlace - Station 10+00 to. 13+15 Use subgradeR-Value = 13.0 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 fromTable 608.413 Highway Design Manual GE = .55 feet for AC yields actual thickness = 2.65 inches Use 4.0 inches of A - City Minimum GE for 4.0 inches Of AC =.83 feet GE for base =(0;0032)( 5.0)(100-13.0) -.83 =.56 feet from Table 608 4B Highway Design Manual with GF for Class 2 base = 11 Base thickness # 6.09 inches 7 Use base thickness = 7.0 inches Design Street Structural Section *** Asphalt Concrete Thickness = 4.0 inches Class 2 Aggregate Base Thickness = 7.'0 inches - N Luecite Place - Station 12+00 to 14+00 Use subgrade R-Value = 35.0 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)+0.21,=.55 feet frOm Table 608:4B Highway Design Manual GE = 35 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)(100-35.0) -'."83 = 21 feet from Table'608.413 Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 2.25 inches Use base thi ess= 4.O inches, City Minimum Design Street Structural Section Asphalt Concrete Thickness = 4 0 inches Class 2 Aggregate Base Thickness = 4.0 inches. Project No. 06403-52-13 September 27, 2004 V FIGURE 1 (Continued) V V PAVEMENT SECTION CALCULATIONS VILLAGESOF LA COSTA THE GREENS Luecite Place— Station 10+00 to 12+00 Use subgrade R-Value = 16.0 Traffic Jndëx (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 40 inches of AC =,.83 feet • V GE for base =(0.0032)( 5.0)(100-16.0) .83 =.51 feet • from Table608.4B Highway Desin Manual with GF for Class 2 base =. 1.1 Base thickness 5.57 inches ' Use base thickness = 6.0 inches *** Design Street StructuraiSection Asphalt ConcEete Thickness = 4.0 inches. Class 2 AggregatéBae Thickness = 6.0 inches. /