STUDY ON SOUNDNESS EVALUATION OF BRIDGE SLABS BY FALLING WEIGHT DEFLECTOMETER

In proper maintenance for bridge slabs, deflection measurement of bridge slabs by falling weight deflectometer (FWD) is one of the soundness evaluation methods. The FWD is the non-destructive testing method for obtaining the slab deflections in-situ. In this research, we focused on the deflection area calculated from the deflection measurement as one of the soundness evaluation indexes for the bridge slabs and investigated it by elastic finite element (FE) analysis based on the thin plate theory simulating the fatigue damage by changing the flexural rigidity of reinforced concrete (RC) slabs. As the results, the deflection area in the transverse direction to the bridge axis correlated well with the deflection at the loading point, and the deflection area in the longitudinal direction was also found to be a good correlation with the deflection at the loading point by limiting its calculation length considering the characteristic of deflection curve. These relationships were similar not only in the simply supported slabs but also in the continuously supported slabs. Furthermore, in order to verify the analytical results, the deflection measurement was carried out on actual bridge slabs newly constructed. Then, the measured results had the same trend with the analytical results.