Seismic performance and damage analysis of replaceable steel coupling beam with slab

Abstract

In this study, quasi-static tests were conducted on four replaceable steel coupling beams (RCBs) with slabs to investigate both slab damage and the mechanical properties of the RCBs. Four RCB specimens were fabricated and tested, each with different slab configurations or RCB construction measures. The experimental results showed that the use of engineered cementitious composites (ECC) materials significantly reduced the crack width of the slotted slab; the non-uniform section height of non-yield beam segments reduced both the crack width and the number of cracks in the slab; the arrangement of prestressed tendons and concrete-filled steel tubes (CFSTs) increased the shear strength of RCB by 16 % but simultaneously decreased its deformation capacity by 21 %. Finite element analysis revealed that specimens SCB1 and SCB2 had large residual slab deformations at the end of loading, which was unfavourable for controlling the slab damage; the axial constraint could result in a substantial axial pressure on the steel link during the unloading stage, ranging between 0.68 and 1.52 times its shear capacity, which complicated the replacement process of the link; the axial tension caused by slab deformation increased the shear strength of the steel links with varying length ratios by 1.06–1.27 times. Therefore, when designing RCBs, it was necessary to account for the slab's impact on the RCB's shear strength.