Parametric Study on the Structural Behavior and Failure Mechanism of Skewed Inverted-T Bent Caps

Abstract

In the past several decades, the inverted-T bent caps (ITBCs) have been frequently used as an innovative type of bridge superstructure worldwide. In some specimens, the bent caps have to be skewed to meet the landscaping requirements. However, the traditional design of ITBC simply flares the transverse shear reinforcements out in skewed ITBCs, which brings significant inconvenience. In order to reduce the construction cost, an alternative skew arrangement with all the reinforcement arranged in parallel throughout the bent cap is recently adopted by Texas Department of Transportation (TxDOT). To investigate the feasibility of this technique, the shear reinforcement arrangement, as well as three other major parametric variations: shear reinforcement spacing, skew angle, and loading position, are studied regarding their effects on the behavior of skewed ITBCs. A total of 17 numerical models are simulated, among which three specimens are verified and validated by experimental results. The same modeling scheme and material parameters are applied to the remaining specimens. The analytical results indicate that the load-displacement curves of ITBCs are not notably changed by the proposed skew reinforcement arrangement, while the reinforcement spacing affects the ultimate capacity and ductility to a limited extent. The increase of the skew angle significantly affects the performance and failure modes. Meanwhile, a modified practical equation for the edge extension length of skewed ITBCs is proposed based on the parametric analysis of varying loading positions.