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Home My WebLink AboutCT 05-15; LA COSTA OAKS NEIGHBORHOOD 3.1, 3.3-3.5; PAVMENT RECOMMENDATIONS; 2008-07-0910 GEOCON INCORPORATED GEOTECHNICAL CONSULTANTS Project No. 06105-52-22A July 9, 2008 LC Oaks 3.3, LLC C/ ColRich 4747 Morena Boulevard, Suite 100 San Diego, California 92117 Attention: Mr. Steve Butler Subject: VILLAGES OF LA COSTA - THE OAKS NORTH CORTE PANORAMA - STATIONS 10+50 THROUGH 15+50 SITIO BAHIA - STATIONS 10+00 THROUGH 12+50 SITIO CALIENTE -STATIONS 10+00 THROUGH 16+48 CORTE ALTURA -STATIONS 10+00 THROUGH 14+50 CARLSBAD, CALIFORNIA PAVEMENT RECOMMENDATIONS Dear Mr. Butler: In accordance with your request, we obtained subgrade soil samples from Corte Panorama Stations 10+00 to 15+50, Sitio Bahia Stations 10+00 through 12+50, Sitio Caliente Stations 10+00 through 16+48 and Corte Altura Stations ,10+00 through 14+50. After collection, we performed Resistance Value (R-Value) tests on the samples. Based on conversations with the project civil engineer from Hunsaker and Associates San Diego Incorporated, we understand that a Traffic Index (TI) of 5.0 has been assigned to the subject roadways. Subgrade soil consists predominately of silty to clayey sand with gravel, and typically exhibits moderate to high R-Value characteristics. We performed the laboratory R-Value tests in accordance with ASTM D 2844 (California Test Method No. 301). The results of the laboratory tests and the corresponding roadway station numbers are presented in Table I. Based on laboratory testing, we calculated the pavement sections in 'general in accordance with California Department of Transportation Highway Design Manual and the City of Carlsbad Minimum Structural Standard GS-17. The pavement sections are presented in Table II and the calculations presented in Figure 1. Final pavement section approval should be obtained from the City of Carlsbad. Asphalt concrete should conform to Section 203-6 of the Standard Specifications for Public Works Construction (Greenbook). Class 2 aggregate base materials should conform to Section 26-1.02A of the Standard Specifications of the State of California, Department of Transportation (Caltrans) or approved equivalent. Additionally, materials should conform to City of Carlsbad specifications. Prior to placing base materials for roadways and curb/gutter, the upper 12 inches of subgrade 'sh'otrl be scarified, moisture conditioned as necessary, and compacted to a dry density of at least 95 percent of the laboratory maximum dry density in accordance with ASTM D 1557. The upper 12 inches of 6960 Flanders Drive U San Diego, California 92121-2974 0 Telephone (858) 558-6900 U Fax (858) 558-6159 subgrade beneath areas to receive concrete sidewalks should be compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content. The base materials 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. The asphalt concrete should be compacted to a density of at least 95 percent of the laboratory Hveem density in accordance with ASTM D 2726. 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 saturation of the subgrade materials and subsequent pavement distress. To reduce the occurrence for such situations, a minimum drainage gradient of at least 1 percent should 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 Michael C. Ertwine Shawn Weedon Senior Staff Geologist GE 2714 MCE:SWlmc (2) Addressee . oFESsi0,, (3/del) ColRich Job Site Trailer s WP Attention: Mr. Larry Willis (:..mail) Hunsaker& Associates Attention: Mr. David Blalock OF C Project No. 06105-52-22A - 2 - July 9, 2008 FIGURE .1 PAVEMENT SECTION CALCULATIONS FOR LA COSTA OAKS NORTH - NEIGHBORHOOD 3.3 SOUTH Corte Panorama - Stations 10+00 through 12+50 Use subgrade R-Value = 29.0 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 thicknes = 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)(100-29.0) - .83 = .30 feet from Table 608.413 Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 3.30 inches Use base thickness = 3.5 inches Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 4.0 inches. Corte Panorama - Stations 12+50 through 15+50 Use subgrade R-Value = 29.0 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)(100-29.0) - .83 = .30 feet from Table 608.413 Highway Design Manual with GF 'for Class 2 base = 1.1 Base thickness = 3.30 inches Use base thickness = 3.5 inches *** Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 4.0 inches. Project No. 06105-52-22A July 9, 2008 FIGURE 1 (Continued) PAVEMENT SECTION CALCULATIONS FOR LA COSTA OAKS NORTH - NEIGHBORHOOD 3.3 SOUTH Sitio Bahia - Stations 10+00 through 12+50 Use subgrade R-Value = 37.0 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)(100-37.0) -.83 = .17 feet from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 1.91 inches Use base thickness = 2.0 inches Design Street Structural Section *** Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 4.0 inches. Sitio Caliente - Stations 10+00 through 13+50 Use subgrade R-Value = 27.0 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)(100-27.0) - .83 = .33 feet from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 3.65 inches Use base thickness = 3.5 inches Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 4.0.. inches. Project No. 06105-52-22A . July 9, 2008 FIGURE 1 (Continued) PAVEMENT SECTION CALCULATIONS FOR LA COSTA OAKS NORTH - NEIGHBORHOOD 3.3 SOUTH Sitio Caliente - Stations 13+50 to 16+48 Use subgrade R-Value = 37.0 Traffic Index (TI) = .0 Methodology = çaltrans 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)(100-37.0).- .83 = .17 feet from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 1.91 inches Use base thickness = 2.0 inches - - *** Design Street Structural Section *** Asphalt Concrete Thickness .4.0 inches. Class 2 Aggregate Base Thickness = 4.0 inches. Corte Altura - Stations 10+00 through 14+50 Use subgrade R-Value = 50.0 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)(100-50.0) - .83 = -.03 feet from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = -.36 inches Use base thickness = .0 inches * * * Design Street Structural Section * * * Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness 4.0 inches. Project No. 06105-52-22A July 9, 2008 TABLE I SUMMARY OF R-VALUE TEST RESULTS ASTM D 2844-01 (CALIFORNIA TEST METHOD NO. 301) Sample Number Location R-Value R-1 Corte Panorama— Stations 10+00 to 12+50 29 R-2 Corte Panorama - Stations 12+50 to 15+50 29 R-3 Sitio Bahia -Stations 10+00 to 12+50 37 R-4 Sitio Caliente - Stations 10+00 to 13+50. 27 - R-5 Sitio Caliente - Stations 13+50 to 16+48 37 R-6 Corte Altura -Stations 10+00 to 14+50 ' 50 TABLE II PAVEMENT SECTION RECOMMENDATIONS Traffic Index Asphalt Class 2* Location (TI) R-Value Concrete Aggregate (inches) Base (inches) Corte Panorama— Stations 10+00 to 15+50 5.0 29 4.0 , '4.0 SitioBahia —Stations 10+00 to 12+50 5.0 37 4.0 4.0 Sitio Caliente -Stations 10+00 to 13+50 5.0 27 4.0 4.0 Sitio Caliente - Stations 13+50 to 16+48 5.0 37 4.0 4.0 Corte Altura - Stations 10+00 to 14+50 . 5.0 50 4.0 4.0 Or approved equivalent. Project No. 06105-52-22A . . July 9, 2008