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. v KLEINFEL1)EIt •� ATTACHMENT "B" le7LocaHon' a" �^ R=Value. "'f'f� A/e"lFassiu 600 R. north of River Road 19 42 150 feet north of River Road We understand that it is estimated that 50, 5-axle trucks per day will travel in each direction as part of the aggregate pit operations. The existing pavement appears to be in relatively good condition with low to moderate severity transverse cracks in the pavement section. Some edge cracks were observed in the northbound lane on either side of our second and third borings. No fulling, shoving, alligator-type cracks or other significant distress was observed in the pavement. There does not appear to be a significant amount of truck traffic on this road at the present time. The traffic index for the current pavement is unknown but is estimated to be approximately 6.0. Based on Topic 603 of the Caltrans Highway Design Manual, a daily truck traffic count of 50 equates to a traffic index of 9.0 for a 20-year design life. With an estimated Traffic Index of 6.0 for the existing traffic on Harrold Avenue, the measured Pavement scclion of approximately 4% inches of asphalt over native soil corresponds to the full- depth asphalt section required for a subgrade R-Value of 50. In our opinion, the R-Value test result of 61 is more representative of the silly sand soils in this area. In our opinion, a design R- Value of 50 should be used in pavement section calculations for this project. Based on a design traffic index of 9.0 and a design R-Value of 50, a full-depth section of 8.2 inches is required. Since the existing pavement section consists of an average of 4.3 inches of asphalt, an overly of 4 inches would be required to bring the existing section up to the design pavement section. The full-depth asphalt concrete pavement section was obtained from Table IV of "Flexible Pavement Structural Section Design Guide for California Cities and Counties," Third Edition. We also recommend placing a geotextile, such as Petromat or an equivalent geotextile, over the existing asphalt concrete pavement prior to placement of the new pavement. The purpose of the geotextile will be to reduce the potential for moisture to pass into the existing cracks in the pavement. The geotextile should be installed per the manufacturer's specifications. All pavement materials should conform to the Caltrans Standard Specifications, latest edition. If you have any questions, please contact our office. Respectfully submitted, RECEIVED ECEIVED C'. 5o ��Cmc o Fye JUN 2 8 2002 Patrick C. Dell, G. E. W .e FF m m Senior Engineer 3.3i-GA REM, W_ d P P PCD:ss dTCforECNN�`6F� '4TE OF Cad" 17508b/ST02R 139 Page 2 of 2 Copyright 2(x)2 Klcinfeldminc June 26,20132