Investigation on the failure mechanism of steel-concrete steel composite beam

The internal crack propagation, the failure mode and ultimate load bearing capacity of the steel-concrete-steel composite beam under the four-point-bend loading is investigated by the numerical simulation. The results of load-displacement curve and failure mode are in good agreement with experiment. In order to study the failure mechanism, the composite beam has been modeled, which part interface interaction between steel and concrete is considered. The results indicate that there are two failure modes: (a) When the strength of the interface is lower than that of the concrete, failure happens at the interface of steel and concrete; (b) When the strength of the interface is higher than that of the concrete, the failure modes is cohesion failure, i.e., and concrete are stripped because of the shear cracks at concrete edge.