Collapse-mechanism of Concrete Filled Steel Tube Arch Bridge during strong earthquake

In this paper, dynamic response of a Long-span Concrete Filled Steel Tube Arch Bridge (346m) during strong earthquake was studied with damage model of steel tube and concrete of rib by the explicit dynamic analysis code. Model is built with 2-node explicit 3-D Beam and explicit Thin Structural Shell, and material model is the kinematic hardening model. The development of the arch rib concrete filled steel tube elements from cracking to failure and the bridge from part collapse to the whole collapse of the bridge were studied. The damage and collapse mechanisms during strong earthquake were given of Concrete Filled Steel Tube Arch Bridges. The results show that the material model of Elastic Plastic with Kinematic Hardening model was effective to analyses the damage and collapse of Concrete Filled Steel Tube Arch Bridge. The sections of one eighth of span are weak under strong earthquake motions. The collapse of the bridge occurs until the whole sections of arch ribs are damaged and failed. It indicates that the material nonlinear should be considered for seismic design, and the variable Cross-Section of arch ribs of concrete filled steel tube arch bridge should be seismic checked.