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ADT' <br />Subgrade Condition <br />Crushed Stone Depth, <br />BST Surface Class A2 <br />Poor <br />20 inches <br />0-200 ADT <br />Average <br />16 inches <br />3/4 inch nominal <br />Good <br />16 inches <br />Poor <br />21 inches <br />201-400 ADT <br />Average <br />16 inches <br />3/4 inch nominal <br />Good <br />16 inches <br />Poor <br />24 inches <br />> 400 ADT <br />Average <br />18 inches <br />3/4 inch nominal <br />Good <br />18 inches <br />'ADT to be determined using the most recent edition of the ITE Trip Generation manual. <br />zBST Class A is a Bituminous Surface Treatment Class A as defined in WSDOT Standard Specifications <br />5-02.10), current edition. <br />,HMA shall be used on grades exceeding 10% <br />^Subgrade Conditions <br />Poor Mr=5000 psi <br />Average Mr=10000 psi <br />Good Mr=20000 psi <br />AASHTO SOIL <br />AASHTO SOIL <br />AASHTO SOIL <br />A4, A5, A6, A7 <br />A2 <br />Al, A3 <br />$Crushed stone depth may be reduced based upon on -site soils investigation. <br />Design assumes the area is well drained and not susceptible to frost. <br />Print Table 4-2 <br />Table 4-3 <br />HMA Surfacing and Structural Requirements <br />ADT' Subgrade Condition2 <br />HMA Surface <br />Crushed Stone Depth, <br />Poor <br />2.5 inches <br />11 inches <br />0-200 <br />Average <br />2.5 inches <br />9 inches <br />ADT <br />Good <br />2.5 inches <br />9 inches <br />Poor <br />3 inches <br />12 inches <br />