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FWD deflections from the highest load were used as input into the
equations to predict layer moduli. However, these deflections were
adjusted to equivalent 9-kip deflections to enhance the use of the
prediction equations. Typical deflections, at the highest load level,
were selected from each test site for the moduli computations. Table
6.2 lists the FWD deflections which have been adjusted to a 9-kip load
level.
6.3.2 Dynaflect Layer Moduli Predictions
The Dynaflect data listed in Table 6.1 were used with the appro
priate equations to compute the respective layer moduli for each test
pavement section. The prediction of Ex or E required an estimate of E2
or E respectively. Therefore, the modulus values which were later
determined to be "true" moduli from modeling Dynaflect deflection basins
were used as input to calculate the other modulus value (e.g., Ex or
e2).
For E3 computations, the simplified equation (Equation 4.15) was
used for all test pavements without regard to the limitations of the
equation. This was to illustrate that Equation 4.15 could be applied to
a wider range without much problems. Three equations were used to com
pute the subgrade modulus, E4. These are Equations 4.16 and 4.17,
developed from the theoretical analyses, and Equation 4.35 which was
originally developed from the analysis of field measured Dynaflect
deflections on test pavements from Quebec, Canada and Florida.
Table 6.3 lists layer moduli predictions from the Dynaflect equa
tions. The asphalt concrete modulus, E using "true" E2 values as
input were computed for most of the sections. Although most of the E2