RMODS 2.0: User's Manual (1939-2)

The program described in this report, developed by the Texas Transportation Institute for the Texas Department of Transportation, aids engineers in evaluating the structural characteristics of rigid pavements. The program, RMODS 2.0, (Rigid Modulus, version 2) analyzes deflection data collected with the Falling Weight Deflectometer (FWD). Technical details of the calculation procedures are given in companion report 1939-3F. The RMODS program has the following capabilities:1. backcalculate slab and subgrade rigidities using Hertz or Westergaard models,2. backcalculate slab and subgrade rigidities using layered elastic theory,3. calculate Load Transfer Efficiency (LTE) at joints, and4. detect the presence of subslab voids at joints.This program requires careful attention during FWD testing to ensure that the deflection data can be used by the RMODS program. Four FWD drops at varying load levels must be recorded at each test location. There must be sensor readings at -305, 0, 305 and 1525 mm (-12, 0, 12 and 60 ins) from the test plate. When calculating LTE, the sensor at -305 mm is placed on one side of the joint, with the load plate and remaining sensors on the other side. Backcalculation of E, l, and k can be performed either at center slab or at a free edge. RMODS 2.0 includes subsystems for data input/data conversion, LTE/VOID calculation, backcalculation, printing and delineation of LTE/VOID or backcalculation results.