Shear resistance of retrofitted castellated link beams: Numerical and limit analysis approaches

Abstract

This paper deals with the cyclic behavior and shear capacity of non-compact steel castellated link beams (CLBs) using finite element analysis. To enhance the shear resistance and inelastic rotation capacity of such vulnerable link beams, some retrofitting strategies are explored and examined. To this end, a three dimensional finite-element model using ABAQUS is developed for the inelastic nonlinear analysis of the unstiffened and stiffened CLBs. It was found that unstiffened short CLBs cannot reach the required inelastic rotation capacity of 0.08 rad as per the Seismic Provisions for shear links. However, two strengthening strategies were found that can be used to make their cyclic behavior more stable and increase their inelastic rotation capacity to an acceptable value as per the Provisions. Furthermore, in order to determine the ultimate shear resistance of unstiffened and stiffened CLBs, a theoretical formula based on the upper-bound theorem of limit analysis and a refined collapse mechanism was proposed. It was shown that the limit analysis results are in good agreement with the FEA predictions.