Composite CFST column to H-shaped steel beam joint: Experimental and numerical investigation

Abstract

Conventional CFST column-to-steel beam connection has excellent collapse-resist capacity, good plastic deformation, and high energy dissipation. However, it makes reconstruction challenging after extreme inelastic deformation in a severe earthquake. This paper proposes a self-centering (SC) composite CFST column to H-shaped beam joint (SCCCB joint) using post-tensioned (PT) tendons. The residual deformation of the splicing column can be greatly reduced under the action of pre-tension tendons. Cyclic loading tests were performed on five 1/3 scale test specimens with the main parameter of axial compression ratio (n = 0.10, 0.12, 0.15, and 0.17) and steel tendon types (with or without cutting processing) to investigate the cyclic behaviour and SC performance. The finite element models were established to capture the stress distribution of the joints. Finally, the seismic and SC performance of the joints were studied by the parametrical analysis including five parameters: width-thickness ratio of steel tube (D/t), diameter, number and spacing of steel tendons (d, ns and s), and connecting diaphragm strength (fy,a). The SC performance can be improved with the increase of ns. The bending capacity of the joints increased with the increase of n, D/t, d and fy,a.