THEORETICAL STUDY ON BOND STRENGTH BETWEEN SHAPED STEEL AND CONCRETE IN SRC COMPOSITE STRUCTURES

Based on the experimental study of pull-out, push-out, pull-push cycle, and short-column specimens on bond-slip behaviors between shaped steel and concrete, the distribution of bond stress on the interface of shaped steel and surrounding concrete is obtained. The shifts of 3 parts (chemical adhesive action, friction resistance and mechanical interlock) that compose the bond strength are measured respectively. According to the velocity accommodation mechanism, the fretting wear characteristics of adhesive interface of shaped steel and surrounding concrete are investigated. The harmony between the load-slip curves in bond-slip tests and the producing and evolving process of ruptured concrete are demonstrated. The experimental results show that the weakness of cooperative bearing capacities of steel and concrete just rests with the shear-slip failure on their adhesive interface, so a mechanical model of bond failure on the interface is established in delamination theory. The producing and transforming laws of friction resistance and mechanical interlock are proposed. The bond strength is quantificationally analyzed in plastic ultimate theory. The upper limit of bond strength is deduced and some material parameters affecting bond behaviors are discussed theoretically. All these may contribute to the further analysis of bond-slip performance in SRC composite structures.