Rotational stiffness of precast beam-column connections with steel fiber-reinforced concrete in corbel and beam dapped-end

Abstract

Abstract This paper investigates the semirigid behavior of a precast beam–column connection with a column corbel and a beam dapped-end using a three-dimensional nonlinear finite element model and steel fiber–reinforced concrete in the force-transfer regions. The numerical model was calibrated and validated against experimental results, including moment–rotation response and failure mode. The model incorporates nonlinear behavior, enabling the assessment of force-transfer mechanisms and rotational stiffness. Under positive bending moments, the simulations reproduced the experimental trend and indicated that the response is mainly governed by the dowels and their interaction with the surrounding concrete. The results show that the structural response depends not only on dowel diameter and spacing but also on the number and arrangement of dowels participating in force transfer, affecting stress redistribution and global efficiency. Under negative bending moments, continuity reinforcement governed the response, increasing moment capacity more significantly than rotational stiffness while preserving the semirigid behavior of the connection. The results also indicate that steel fibers contributed to a more distributed cracking pattern and smoother stiffness degradation in the force-transfer regions.