Mechanical behavior of steel–concrete composite joints in railway hybrid cable-stayed bridges

Abstract

The mechanical behavior of steel–concrete composite joints (SCCJs) on a high-speed railway hybrid cable-stayed bridge was investigated by performing a model test with a scale of 1:2.5. Structural responses that included stress distributions, deformation characteristics, crack pattern, and failure mode were presented and discussed. Two simplified formulas for deflection and rotation were proposed to evaluate the deformation performance of the SCCJ. The results indicated that the SCCJ still exhibited sufficient strength and excellent deformation performance under twice the design load for which the SCCJ could satisfy the high safety and smoothness requirements for supporting a high-speed train in motion. An uneven stress distribution among shear connectors was also found. The test results also show that the concrete girder adjacent to the SCCJ failed earlier than the SCCJ, which indicates that the flexural resistance of the SCCJ is higher than the adjacent concrete girder. Furthermore, parameter analyses that employed a nonlinear finite element model were conducted to provide an insight into the load transfer mechanism. The numerical results indicated that approximately 33.0% and 5.8% of axial force was transferred through the end and front bearing plates, respectively. The thickness of the end bearing plate would definitively influence the axial force transfer and slip distribution, while that of the front bearing plate had only a slight influence on them. The numerical results also revealed an uneven load distribution among the multilayered shear connectors.