Study on mechanical performance of composite beam with innovative composite slabs

摘要

A new type of composite beam which consists of a wide flange steel shape beam and an innovative type of composite slab was introduced. The composite slab is composed of concrete slab and normal flat steel plates, which are connected by perfobond shear connectors (PBL shear connectors). This paper describes experiments of two large-scale specimens of that composite beam. Both specimens were loaded at two symmetric points for 4-point loading status, and mechanical behaviors under hogging and sagging bending moments were investigated respectively. During the experiments, the crack patterns, failure modes, failure mechanism and ultimate bending capacity of composite beam specimens were investigated, and the strains of concrete and flat steel plate as well as steel shapes were measured and recorded. As shown from the experimental results, composite actions were fully developed between the steel shape and the composite slab, this new type of composite beams was found to have good mechanical performance both under hogging and sagging bending moment with high bending capacity, substantial flexure rigidity and good ductility. It was further shown that the plane-section assumption was verified. Moreover, a design procedure including calculation methods of bending capacity of this new type of composite beam was studied and proposed based on the experimental results, and the calculation methods based on the plane-section assumption and plastic theories were also verified by comparisons of the calculated results and experimental results, which were agreed with each other.