Plastic Hinge Model And Seismic Response Analysis Of The Corroded Steel Structure

Because of its good mechanical performance, economic performance and service performance, steel structure has been widely used in large bridges, offshore oil platforms, industrial and civil buildings, and its good ductility was preferred in seismic design. However, the protection and construction measures were often difficult to protect steel structure engineerings against the corrosion, which were in industry and marine atmospheric corrosion environment for a long term. Because of the pit in the surface of corroded steel structure, the plasticity and fracture toughness were reduced, and the crack propagation speed was increased. This has an effect on the seismic performance of steel structure engineering undoubtedly in the follow-up period. The seismic performance evolution of corroded steel structure is a ineluctable problem for the evaluation of seismic performance of steel structure engineering in the earthquake fortification area.According to the rapid corrosion in the neutral salt fog environment and tensile test of the Q235 steel in the laboratory, the influence of corrosion on mechanical properties of Q235 steel was studied, and the influence of corrosion on the length and the rotation capacity of plastic hinge of steel flexural member was analysed, and the calculation model of plastic hinge length and ductility was proposed.With the help of finite element software ANSYS, the corrosion degree and the axial compression ratio as parameters, the influence of corrosion on strength, stiffness, hysteretic curve, skeleton curve, ductility, energy dissipation capacity and failure mechanism of the eccentric compression steel member under cyclic loading was studied.With the help of the finite element analysis software SAP2000, and static elasto-plastic analysis method(Push-over method)was used. The influence of corrosion on story displacement, the position of weak layer and the plastic hinge formation of the plane steel frame was analysed, and the earthquake disaster mechanism and seismic performance evaluation method of corroded steel structure was investigated.