A modified cohesion-friction model for simulating the contact behaviours of hinge joints in hollow-slab bridges

Hollow slabs have been widely used for medium- and small-span bridges, but hollow slab bridges occasionally encounter connecting problems. The key to solve the problems is to ascertain the contact mechanism and subsequently find an approach to simulate them. This paper focuses on developing a cohesion–friction model for concrete interfaces and implementing nonlinear analysis of hollow-slab bridges through a general finite element software. First, the positions and moving tendencies of interfaces in hinge joints are investigated; the stress states on these interfaces can be divided into compression‒shear, tension–shear and pure shear states. Second, a simplified cohesion–friction model for concrete interfaces is proposed in which the shear resistance under different stress states is deduced based on Mohr’s strength theory. Third, the accuracy of the proposed model is verified by a conventional cohesion–friction model. Finally, the proposed model is applied to predict the behaviours of hollow-slab bridges in finite element analysis. Research results indicate that the shear resistance of a concrete interface can be predicted by the proposed model and the behaviours of hollow-slab bridges can be represented by the finite element model. The slab deflection is seriously affected by the friction coefficient and shear strength of the interfaces; hence, it is necessary to calibrate these indexes in advance of numerical simulation analysis.