Seismic performance of bolted connection between H-section beam and SST column welded with inclined braces

Abstract

To improve the construction efficiency and achieve a rigid connection under design load, an innovative H-section beam-to-square steel tubular (SST) column bolted connection with inclined braces is proposed. The innovative bolted joint can realize bolted assembly between beam and column as well as between column and column, and it exhibits satisfactory stiffness and strength under earthquake with few bolts. Three groups of beam-column bolted joints with different types of inclined braces were designed, and tests and finite element analysis (FEA) were implemented under cyclic loading. The mechanical behaviour, deformation process, failure modes, and energy dissipation of all specimens were observed, and the effect of the type and length of inclined brace on seismic behaviour of joints was analyzed. The results showed that all specimens exhibited satisfactory ductility, plastic deformation capacity and energy-dissipation capacity. All tested joints with inclined braces showed failure mode of severe local buckling of beam section outside the connecting area, and the strength, stiffness and energy dissipation capacity of bolted joints with inclined braces were significantly improved. The joints with an H-shaped brace dissipate more energy than those with a channel brace, particularly when the web of the H-shaped brace is perpendicular to the beam web. Furthermore, the strength, stiffness and energy dissipation capacity of innovative joints with long diagonal braces are higher than those with short diagonal braces. On the basis of the test results and numerical analysis, simplified calculations for the slip resistance, yield resistance and ultimate resistance of the bolted joints with inclined braces are proposed and validated against tests.