Anchorage design method and interfaces bond behavior of steel encased concrete member

In order to research the natural bond performance between steel and concrete with different interfaces in steel encased concrete structure, four specimens were designed to launch a test under the monotone push-out loading. Four conditions were considered in this test, including steel outer flange, inside flange, web and whole side bonding with the concrete. Failure process and modes of these specimens were obtained. Load-slip curves and ultimate bond strength were obtained and the different interfaces bond strength between steel and concrete were analyzed. Besides, three specimens with studs in steel were fabricated to deeply research the bond anchorage performance of steel encased concrete member. Three specimens with studs welded in steel, including studs welded in steel outer flange, steel web and outer flange uniting with web, were respectively considered. The bond and slip behaviors of steel encased concrete specimens with studs were obtained and studs locations influence on the bond behavior of steel encased concrete was analyzed. Finally, the minimum anchorage length calculation formulas were established under the conditions of natural bond, steel with studs, respectively. The results show that different interfaces bond strengths of steel encased concrete members are not equal. The bond strength in steel web is the minimum, while the bond strength in inside flange is the maximum. Studs welded locations influence on bond strength a bit, the contrast results show that specimens ductility with studs in web is much better than that in flange.