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Table S. Coefficients for GE Curves in Equation 4. <br />Subgrade R-Value <br />Regression <br />Coefficient <br />5 <br />10 <br />15 <br />20 <br />30 <br />45 <br />60 <br />75 <br />a <br />27.086 <br />31.639 <br />29.676 <br />28.308 <br />28.095 <br />19.418 <br />22.164 <br />20.954 <br />b <br />1.967 <br />1.942 <br />1.963 <br />2.201 <br />2.218 <br />2.340 <br />2.467 <br />2.571 <br />c <br />-2.201 <br />-1.878 <br />-1.969 <br />-2.114 <br />-2.115 <br />-3.020 <br />-2.901 <br />-3.526 <br />d <br />10.818 <br />9.659 <br />10.446 <br />11.271 <br />11.504 <br />17.645 <br />16.829 <br />20.845 <br />f <br />15.624 <br />10.104 <br />9.285 <br />7.658 <br />5.035 <br />9.386 <br />4.903 <br />3.794 <br />Estimate required GE With and Without <br />This component of the analysis method estimates the GE required as if the pavement were to be <br />newly designed and constructed. In other words, if the additional heavy vehicles were known at <br />the time of design and construction, the pavement design would have been different in order to <br />accommodate them. <br />Using the pavement design chart, the two ESAL calculations (with and without the additional <br />heavy vehicles) and the subgrade R-value are used to determine the pavement structure GE that <br />would be required both with and without the additional heavy vehicles. While this can be done <br />by hand using the design chart, the GEDesign equation (equation 4) can be used to estimate these <br />values. <br />With these design GE values - with and without the additional heavy vehicles - their impacts to <br />the pavement in terms of additional bituminous material can be estimated. <br />Estimate Impacts <br />The impacts to the pavement structure attributable to the additional heavy vehicles are computed <br />by the analysis method in three ways - additional bituminous material required at design and <br />construction, pavement life consumed, and pavement performance degradation. <br />Estimate Additional Bituminous Material at <br />The additional bituminous material that would be required in the original design and construction <br />if the additional heavy vehicles had been known is one way of demonstrating the impacts of <br />those vehicles. This is computed with a simple equation - taking the difference in GEDesign <br />and dividing by the GE provided by bituminous material, as shown in equation 5. <br />hl-add - <br />(GEDesign-With - GEDesign-Without ) <br />where: <br />GEsit <br />(5) <br />hl-add = additional bituminous thickness required, <br />GEDesign-with = Total granular equivalent with additional heavy vehicles, <br />GEDesign-without = Total granular equivalent without additional heavy vehicles, <br />GEBit = Granular equivalent of bituminous material (usually 2.25) (1). <br />19 <br />