Validation of a laboratory method for accelerated fatigue testing of bridge deck panels with a rolling wheel load

Abstract

The Western Transportation Institute (WTI) was engaged by the California Department of Transportation (Caltrans) to investigate the performance of various bridge deck rehabilitation surface treatments. This study requires that full-scale reinforced bridge deck slabs be tested in a laboratory environment. The deck slabs are to be tested by applying repeated passes of a rolling wheel load to damage the slabs to certain levels of deterioration. The slabs will be mounted in a frame for testing to impose specific support constraints necessary to generate realistic box girder bridge behavior. The intent of the present study was to design the panel support frame and validate that it provides the required restraint conditions needed for testing as well as to determine if it will be possible to generate the damage required in future deck slabs in a realistic time frame. This validation was accomplished by performing an experimental study in which a sample test slab was loaded to failure in one of the bays of the support frame. The slab was loaded with a stationary hydraulic jack over a contact area resembling that of a standard dual tire footprint. In addition, the finite element modeling software, ANSYS, was used to model the laboratory test to aid in interpreting the experimental results. The results from the laboratory test and the related findings from the finite element model were presented in terms of cracking behavior, deflection histories, strain measurements in the steel reinforcement, ultimate capacity, and mode of failure. The results were used in conjunction with the finite element model to validate the performance of the support frame. It was determined that the support frame provides the restraint conditions needed to create the in-service stress conditions of interest in the bridge deck slabs. A fatigue life model that was developed by past researchers was used to assess the expected performance of the deck specimens under the proposed rolling wheel loads.