Experimental study on skew inverted-T bent caps with minimum traditional and skew transverse reinforcing

Abstract

In this paper, the shear behavior of six full-scale Inverted-T Bent Caps (ITBC) specimens with skew angles of 30°, 45°, and 60° are reported to study the effect of skew angle and rebar arrangement on structural performance. The transverse reinforcement in skewed ITBCs is designed as per the traditional methods the TxDOT Bridge Design Manual LRFD, which conform to the AASHTO LRFD Bridge Design Specifications. The traditional design of flaring the transverse rebar in skew ITBCs brings notable difficulty in manufacturing. An alternative way is to apply uniform skewed reinforcing, which is compared to traditional design in this research. The minimum ratio of transverse reinforcement required by AASHTO LRFD specifications was adopted in this research to investigate the most unfavorable design. The load–displacement curves, the internal force diagrams, the strength and displacement capacity, and the strain measuring results are reported in detail. The specimens with a skew angle of 30° or 45° fail in shear-critical mode, while the specimens with a skew angle of 60° fail in torsion-critical mode. The experimental results show that replacing the traditional reinforcement with the skew reinforcement does not reduce the capacity of ITBCs. The cracking behavior of ITBCs with skew rebar are better than the ITBCs with traditional rebar. Based on the extensive experimental study on ITBCs, general design guidelines for the design and construction of the skewed reinforcing in ITBCs are provided.