Behavior of continuous steel-concrete composite beams with web openings

Abstract

In order to investigate the mechanical performance and load carrying capacity of continuous steel-concrete composite beams with web openings, five continuous composite beams with web openings and a contrasting continuous composite beam without web openings were tested through two symmetric point loads. Nonlinear finite element analysis was also conducted, in which the slab thickness and the reinforcement ratio of slabs were selected as the major parameters. The main results of this test were concluded as follows: (1) Web openings not only decrease the stiffness and ultimate load carrying capacity of continuous composite beams but also give rise to the redistribution of vertical shear force between the cross section of the steel beam and the concrete slab at the web opening region. (2) The plane hypothesis is not satisfied at the web opening region. The failure mode of continuous composite beams with web openings is the shear failure of concrete slab in the region near the opening, and the result also indicates that the shear bearing capacity at the span with web openings become a critical factor in controlling design. (3) Meanwhile, by increasing the thickness and reinforcement ratio of a concrete slab, the ultimate load carrying capacity and ductility of continuous composite beams increased, which can be used to the enhancement of web opening region. (4) In addition, based on the experimental results, a finite element mode was established for composite beams with web openings, and good agreement was obtained between the tested results and the numerical results.