DETERMINATION OF DEFLECTION BASIN USING PAVEMENT MODELLING COMPUTER PROGRAMS AND FINITE ELEMENT METHOD
Abstract
Several methods can be used to model pavement structures, namely multilayered
elastic theory (MET), finite element method (FEM), or finite difference
method (FDM). In this study, three computer programs, KENLAYER and EVERSTRESS
5.0 which are based on MET, and ANSYS, representing the FEM, are used in Falling
Weight Deflectometer (FWD) test on a pavement structure to determine
deflection basin. The deflection basin was developed by using the results of
vertical deflection from each sensor of an FWD test. In this study, a pavement
structure was modelled for three locations of FWD tests, namely CH 200, CH 1450,
and CH 2300. Based on the comparative study, all computer programs show good
potential in determining deflection basin, with small percentage of Root Mean
Square Error (RMSE) of between 1.00% to 4.31% for all models developed by the
computer programs and field measurement. In order to obtain a higher accuracy
of the FEM, the models considered the dynamic loading, increasing size of model
geometry, as well as the reduction of the mesh element sizes. Moreover, changing
from static to dynamic loading led to the reduction of percentage in RMSE for CH
200 from 2.41% to 0.94%. Decreasing size of closer elements of loading region also
results in lower percentages of RMSE, calculated at 4.21% to 3.63% and 1.20% to
1.18% for CH 1450 and CH 2300, respectively. FEM, therefore, is found to be the
best method for determining deflection basin of FWD in comparison to other MET
computer programs.