Transverse bending mechanism of partially encased joint with perfobond connectors in composite bridge with corrugated steel webs

The out-of-plane bending stiffness of the corrugated steel web (CSW) is much larger than that of flat steel webs, resulting in significant transverse bending moments in the joint between the CSW and concrete slabs in a composite bridge. The partially encased joint between the CSW and bottom concrete slab has gained popularity due to its favorable durability and construction convenience. This study investigates the mechanical behavior of the partially encased joint with perfobond connectors under transverse bending moments. Firstly, an experimental test is conducted to obtain the failure mode and strain distributions. Then, nonlinear finite element simulations are performed to reveal the transverse bending mechanism of the joint. Parametric analysis is subsequently conducted to investigate the influence of the perfobond connector arrangement. The results indicate that the partially encased joint with perfobond connectors presents a concrete cone failure mode under transverse bending moments, with the tensile capacity of the topmost connector controlling the cracking moment. The transverse bending resistance primarily arises from the horizontal tensile forces and vertical shear forces of the perfobond connectors, as well as the horizontal and vertical contact forces between steel components and concrete. Notably, the horizontal forces contribute to over 80% of the total bending moment. With an increase in the height of the perforated plate, the cracking moment and moment sharing ratios of horizontal forces gradually increase. As the number of perforated holes increases, the cracking moment initially increases and then decreases. Therefore, an appropriate perforated hole spacing is essential to fully utilize the transverse bending capacity of the joint.