Laserfiche WebLink
The South Dakota Catalog Design Method <br />All <br />he South Dakota Catalog Design Vethod <br />A similar approach to the above procedure is suggested for <br />local and other agencies in the state of South Dakota to deter- <br />mine gravel layer thickness. The method is rather crude <br />because it only relies on two parameters, heavy trucks and <br />subgrade support condition. Table 6 represents suggested <br />thicknesses. (3) <br />Table 6: Suggested Gravel Layer Thickness for New Or Reconstructed Rural Roads. <br />Estimated Daily Number of Heavy Trucks Subgrade Support Conditions <br />Suggested Minimum Gravel Layer <br />Thickness,mm (in.) <br />Low 165 (6.5) <br />0 to 5 Medium 140 (5.5) <br />High 115 (4.5) <br />Low 215 (8.5) <br />5 to 10 Medium 180 (7.0) <br />High 140 (5.5) <br />Low 290 (11.5) <br />10 to 25 Medium 230 (9.0) <br />High 180 (7.0) <br />Low 370 (14.5) <br />25 to 50 Medium 290 (11.5) <br />High 215 (8.5) <br />Notes: 1 Low Subgrade support: CBR <3 percent; <br />Medium Subgrade support: 3 < CBR 5 10 percent; <br />High Subgrade support: CBR >10 percent. <br />