Numerical analysis of the mechanical behaviors of girders in jointless bridge considering the grade flat approach slab

The approach slab of the jointless bridge can absorb and transmit the deformation of the girders due to temperature variations. However, the reactions from the approach slab can influence the mechanical behaviors of jointless bridges. The most common type of approach slab in jointless bridges is the Grade Flat Approach Slab (GFAS). The length of the approach slab, the sliding material and the subgrade material can affect the stresses of the approach slabs and the girders. The influence of the approach slabs was usually neglected. In this paper, one Deck-Extension Bridge (DEB) was chosen as the case study. The finite element models of the girders and the GFAS was built. Based on the force-displacement curve and friction coefficient obtain from the lab test, the horizontal and vertical springs were used to simulate the friction in the sliding materials and the supports under the GFAS. The results show that the simulation method of simplified spring is more constrained than the simulation method of shell element, the influence laws of the two connection structures of hinged and fixed are different. The influence of the parameters on the side span is greater than that of the mid span