Seismic performance of the cantilever segment in prefabricated stepped beam–column joints

Abstract

The seismic performance and construction speed of the prefabricated steel structures are greatly influenced by the configuration of the beam–column joints. The stepped beam–column joint proposed in this paper, featuring with flush surfaces on both the upper and lower beam flanges, was designed to satisfy the requirements of favorable seismic resistance and high installation efficiency. Notably, the junction between the stepped cantilever segment and the stepped beam segment is crucial in the stepped joint. Therefore, cyclic loading tests were conducted on two cantilever specimens with different connection forms to determine their seismic behavior and failure modes. The experimental results indicated that the connection forms have a minor effect on the elastic phase behavior. However, a significant influence was observed on the ultimate load‐bearing capacity and energy dissipation. The result also indicated that the specimen with a thicker end plate exhibited excellent seismic performance, with favorable load‐bearing and plastic deformation capacity. The seismic performance of the joint specimen with U‐shaped latch was inferior, with the welding seam on the flange connected to the end plate tearing prematurely due to the stress concentration. Besides, elaborate finite element models were established, which were confirmed by the test results. Finally, parametric analysis considering the effect of end plate thickness was conducted, and the bolts' forces during the loading progress on the connection surfaces were analyzed. The result indicated that the joint's load‐bearing capacity and stiffness would decrease with the reduction of end plate thickness.