Study on transverse structural performance of large cantilever steel-UHPC composite bridge deck

This study investigates the transverse structural performance of an ultrahigh performance concrete (UHPC) lightweight composite deck (LWCD) in a large cantilever cable-stayed bridge with an ultra-wide single cable plane, which is different from previous double-cable-plane cable-stayed and suspension bridges. To this end, large-scale cantilever model testing and linear and nonlinear finite element (FE) modeling are performed. The results show that during the test all cracks were progressively propagated from the fixed end to the cantilever end, and they showed a dense distribution on the UHPC surface at the end of the test. The presence of U-ribs alters the local stiffness and stress distribution, thereby promoting UHPC crack initiation on the top of the left web of the U-rib. In the elastic stage, strain differences between the top and bottom UHPC surface are <30 mu epsilon, showing an approximate axial tension characteristic. In the crack development stage, the strain differences increase with the load, showing a bending-tensile stress characteristic, especially at the top of the U-rib. The bending-tensile stress characteristic becomes more significant from the fixed end to the cantilever end with decreasing girder height. The maximum transverse stress of 10.51 MPa obtained from FE modeling with load combinations is smaller than the nominal cracking stress of UHPC layers (i.e., 10.7 MPa), confirming the linear response and safety of engineering practice.