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Home My WebLink AboutCT 04-04; LA COSTA RIDGE NEIGHEBORHOOD 2.5; PAVEMENT RECOMMENDATIONS SITIO TORUGA & SITIO AVELLANA; 2009-11-25Cr o4O4 GEOCON INCORPORATED GEOTECHNICAL CONSULTANTS 410>) Project No. 07290-52-13 November 25, 2009 City Ventures 4850 Red Hill Avenue, Suite 200 Santa Ana, California 92750 Attention: Mr. Matthew Jansen Subject: VILLAGES OF LA COSTA - THE RIDGE NEIGHBORHOOD 2.5, LOTS 33 THROUGH 66 SITIO AVELLANA -STATIONS 10+00 THROUGH 15+66 SITIO TORTUGA - STATIONS 10+00 THROUGH 15+77 CARLSBAD, CALIFORNIA PAVEMENT RECOMMENDATIONS Dear Mr. Jansen: In accordance with your request, we obtained subgrade soil samples from the subject roadways. 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. Sibgrade soil consists predominately of silty to clayey sand With gravel, and typically exhibits low to moderate R-Value characteristics. We performed the laboratory R-Value tests in accordance with ASTM D 2844 (California Test Method No. 30,1). 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 accordance with California Department of Transportation Highway Design Manual and the City of Carlsbad Minimum Structural Standard GS-1 7. The pavement sections and the Traffic Index are presented in Table II. Calculations for the pavement sections are 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 should 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 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. 6960 Flanders Drive 0 San Diego, California 92121-2974 U Telephone (858) 558-6900 U Fox (858) 558-6159 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 D2726. 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 Senior Staff Geologist MCE:TEM:sc (2) Addressee (3/del) La Costa Ridge Jobsite Attention: Mr. Carlos Paixao (e-mail) Hunsaker & Associates Attention: Mr. David Blalock Trevor E. Myers RCE 63773 (0: cn\z il No. RCE63773 l mm EXP 09/30/10 J,' OF C Project No. 07290-52-13 -2- November 25, 2009 FIGURE 1 PAVEMENT SECTION CALCULATIONS FOR LA COSTA RIDGE - NEIGHBORHOOD 2.5 Sitio Avellana - Stations 13+00 through 15+66 Use subgrade R-Value = 41.0 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)(100-41.0) - .83 = .11 feet from Table 608.4B Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 1.21 inches Use base thickness = 4.0 inches, City of Carlsbad minimum Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 1.0 inches. : Sitio Avellana - Stations 10+00 through 13+00 Use subgrade R-Value = 40.0 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)(100-40.0) - .83 = .13 feet from Table 608.413 Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 1.38 inches Use base thickness = 4.0 inches, City of Carlsbad minimum Design Street Structural Section Asphalt Concrete Thickness = 4.0 inches. Class 2 Aggregate Base Thickness = 4.0 inches. Project No. 07290-52.13 S November 25, 2009 FIGURE 1 (Continued) PAVEMENT SECTION CALCULATIONS FOR LA COSTA RIDGE - NEIGHBORHOOD 2.5 Sitio Tortuga - Stations 13+00 through 15+77, Use subgrade R-Value = 23.0 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)(100-23.0) - .83 = .40 feet from Table 608.413 Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 4.35 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. Sitio Tortuga - Stations 10+00 through 13+00 Use subgrade R-Value = 20.0 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)(100-20.0) - .83 = .45 feet from Table 608.413 Highway Design Manual with GF for Class 2 base = 1.1 Base thickness = 4.87 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. 11 Project No. 07290-52-13 November 25, 2009 Sitio Avellana— Stations 10+00 through 13+00 5.0 Sitio Tortuga— Stations 13+00 through 15+77 5.0 Sitio Tortuga— Stations 10+00 through 13+00 5.0 ,*Or approved equivalent. - Traffic Asphalt Class 2* Location R-Value Concrete Aggregate Index (TI) (inches) Base (inches) Sitio Avellana— Stations 13+00 through 15+66 5.0 41 4.0 4.0 40 4.0 4.0 23 4.0 5.0 . . 20 4.0 . 5.0, TABLE I SUMMARY OF R-VALUE TEST RESULTS ASTM D 2844-01 (CALIFORNIA TEST METHOD NO. 301) Sample Number Location R-Value R-1 SitioAvellana — Stations 13+00 through 15+66 41 R-2 Sitio Avellana— Stations 10+00 through 13+00 . 40 R-3 Sitio Tortuga - Stations 13+00 through 15+77 23 R-4 Sitio Tortuga— Stations 10+00 through 13+00 20 TABLE II PAVEMENT SECTION RECOMMENDATIONS Project No. 07290-52-13 November 25, 2009