STRUCTURAL ANALYSIS OF LONG-SPAN COMPOSITE GIRDER CABLE-STAYED BRIDGE WITH THREE PYLONS AT LIMIT STATES

On the background of a long-span composite girder cable-stayed bridge with three pylons for research, this paper analyzes stress of the structure at normal use limited state and bearing capacity limited state by integrally considering the structural geometric nonlinearity, material nonlinearity and interface slip effect in composite girder, and parametrically studies the influence on the internal force of the cable stayed bridge owning to the cable sage effect, material nonlinearity and interface slip effect in composite girder at the bearing capacity limited state. This research shows that the stress and deflection of the structure at the two limited states accord with the code of design and the structure has high load-bearing capacity, and at bearing capacity limited state, the cable sage effect has a small influence on the internal force in the cable-stayed bridge, but the material nonlinearity and interface slip effect in composite girder hold more influence on the structural internal force. It should be pay attention to that all the influences are unfavourable, so the influences of the later two factors shouldn't be neglected in design of this kind cable-stayed bridge.