Effects of bonding between RC slab and steel upper flange on the elasto-plastic behavior of steel-concrete composite girders

In the research sponsored by the National Institute for Land and Infrastructure Management, the development of new design methods for composite girders has been discussed. In this method, various characteristics of the plastic design of composite girders were taken into account. In order to investigate the effects of the bonding at the steel-concrete interface, the three-point bending test was conducted on two composite girders with the same dimension. A detaching agent was applied to the interface between the concrete slab and the steel upper flange to eliminate the bonding. According to the test results obtained in this study, there was little effect of bonding on the maximum strength, and both test specimens exceeded the strength corresponding to the theoretical total plastic moment. Both test specimens with and without bonding reached the ultimate state due to the collapse of concrete of the RC slab.