Experimental and numerical study on the nonlinear performance of single-box multi-cell composite box-girder with corrugated steel webs under pure torsion

Currently, an increasing number of single-box multi-cell composite box-girders with corrugated steel webs (SBMC-CBGCSWs) have been built in China and Japan. However, the torsional stiffness of SBMC-CBGCSW is dramatically decreased due to the employment of thin corrugated steel webs (CSWs). Investigations of SBMC-CBGCSW under pure torsion are relatively limited, therefore, additional research is needed to investigated to guarantee the safety of such bridges. In this paper, an experimental study on four scaled specimens subjected to pure torsion is conducted to understand the effect of the number of cells and spacing of CSWs on the full torsional response of SBMC-CBGCSW. The failure mode, cracking patterns, and buckling patterns of specimens are presented, and a new shear strain relationship between CSWs obtained from experimental results is proposed to evaluate the contribution of inner CSWs to the torsional behavior of SBMC-CBGCSW. Then, finite element analysis (FEA) models are created to compare with experimental results, such as torque-twist curves, shear strains of CSWs and shear strains of concrete slabs. Finally, a parametric study is performed to examine the effect of geometric factors, such as the ratio of width to height, ratio of width to span length, ratio of width to thickness of slab, number of cells and spacing of CSWs, on such bridges under torsion. (C) 2020 Elsevier Ltd. All rights reserved.