Mechanical response of shear connectors in steel-concrete composite beams with steel boxes and precast decks

The steel-concrete composite beam with steel box and precast deck is a new bridge structure. However, studies on the mechanism of a steel box and precast concrete slab connected by a shear key remain scarce. To explore the mutual coupling relationship between the steel box girder and the prefabricated bridge deck slab under a shear key, an experimental model of shear connection between steel box and precast concrete slab was proposed in this work. Finite element analysis and experimental methods were used to develop a push-out test analysis model with 12 symmetrical Ushaped shear keys in three rows and two columns along the longitudinal direction of a precast slab. Using the plastic damage model, the mechanical response characteristics of the shear connection structure, including its force transmission mechanism, stress state, and strain distribution, were analyzed and the accuracy of the calculation results was verified. Results indicate that as the amount of load increases, the compressive stress of the concrete slab expands from the root of the shear key in an arched manner and eventually forms an elliptical table. The load on a single shear key is inversely proportional to its distance from the loading point. The crack load of the concrete slab is 0.47 Pu, and the yield load of the shear key is 0.7 Pu. This study offers a certain reference value for optimizing the design of bridges with a steel- concrete composite girder. © 2019 Eastern Macedonia and Thrace Institute of Technology.