THE CAPACITY OF EMBEDDED SHEAR CONNECTOR STUDS OF COMPOSITE BOX GIRDERS WITH A CORRUGATED STEEL WEB BY PUSH-OUT TESTS AND FEM ANALYSES

To meet the mechanical requirement of an extradosed bridge of composite box girders with a corrugated steel web, an embedded shear connector with studs (ESCS) was designed. To investigate the shear resistance of the ESCS, push-out tests and the corresponding simulation using the finite element method (FEM) were designed and conducted. The mechanical performance and failure mechanism of the specimen were illustrated. According to the bearing mechanism and mechanical properties of the ESCS, an approximate calculation method of the shear resistance was developed. The results show that the shear resistance of ESCSs is higher when the studs are welded from outside the straight plate of the corrugated steel web than from the inner side. The shear resistance of the ESCS is the highest when the pored position is located at the straight plate, followed by that of the upper folded plate and the lower folded plate. The load-deflection curves of the upper folded plate of the corrugated steel web have an obvious strengthening stage, while those of the lower folded plate have almost no strengthening stage. The characteristics of the load-deflection curves of straight plates are between the upper and the lower folded plates. Moreover, the concrete cracking and the formation and development of major cracks occur after the load level exceeds 0.8 times the ultimate strength of the ESCS. The FEM can provide a relatively accurate simulation of the mechanical behavior of the specimen of the push-out test, and reflect the influences of stud welding position and pored position on the shear resistance. The failure mechanism can be illustrated according to the analysis results. By the analysis of both the push-out test and FEM simulation, the shear resistance of the ESCS is found to be provided by the block connector composed of the concrete surrounded by corrugated steel plates and the reinforcing steel, the concrete shear pin in the opening hole and the stud. The relative errors of the shear resistances between the approximate calculation method and the results of the push-out tests are less than 8.93%. The relative errors between the approximate calculation method and the results of the FEM simulations are less than 5.47%. It indicates that the approximate shear resistance calculation method is applicable.