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areas where the subgrade can be improved during construction through either <br />scarification and compaction or soil treatment, a geotechnical report provides <br />recommendations for the scarification -compaction process or the soil amendment <br />process. Full depth AC may also be proposed with aggregate subbase on <br />geotechnical fabric instead of soil treatment. <br />Full depth design shall assume the full -depth AC paving supports the full traffic <br />loading. Any treated subgrade or aggregate subbase shall be considered a working <br />platform for construction and not a structural element of the pavement structure in <br />the pavement design. ^ <br />Design parameters for the AASHTO-approved method for flexible pavement (SN = <br />a1D1 + a2D2M2 + anDnMn) are reflected below. The pavement section shall be designed <br />using the Layered Design Analysis method described in Section 3.1.5 of Part II of the <br />1993 AASHTO Guide. <br />Design traffic, ESAL's, is the expected number of equivalent single axle loads to the <br />pavement over the design period. For all street classifications the design period for <br />new streets, portions of new streets, and rehabilitation of existing streets to fully <br />reconstruct or to remove and replace pavement shall be 30 years, and 20 years for <br />overlays and "mill and fill" street rehabilitation. Design ESAL's shall be calculated per <br />the current ODOT Pavement Design Guide. Annual growth rate shall be 1.5 percent. <br />Table 1, ESAL Annual Conversion Factors, shall be replaced with the following: <br />Table 1— ESAL Annual Conversion Factors <br />ESAL Annual Conversion Factors <br />Number of Axles <br />Flexible Pavement <br />Rigid Pavement <br />One Way Two Way One Way <br />Traffic Data Traffic Data Traffic Data <br />Two Way <br />Traffic Data <br />2 <br />100 <br />50 <br />100 <br />50 <br />3 <br />220 <br />110 <br />270 <br />135 <br />4 <br />320 <br />160 <br />400 <br />200 <br />5 <br />650 <br />325 <br />950 <br />475 <br />6+ <br />650 <br />325 <br />950 <br />475 <br />Standard Bus <br />930 <br />465 <br />1390 <br />695 <br />Articulated Bus <br />1550 <br />775 <br />2320 <br />1160 <br />Serviceability (psi) is the ability of the pavement at the time of observation to serve <br />high-speed, high volume vehicular traffic. Use the following factors. <br />Initial psi = 4.2 <br />Terminal psi = 2.5 <br />Public Improvement Design Standards Manual, 2016. Page 2-31 <br />