Pushover Analysis Of Long Span Tridimensional Steel Truss Arch

Pushover Analysis is widely used in the engineering practice. This kind of nonlinear static procedure not only overcomes the shortages of traditional linear analysis, such as response spectrum method, but also avoids problem of the excessive computation price of Time History Analysis. It is an important tool to implement the performance-based earthquake-resistant design. Pushover Anaysis is widly used to evaluate the seismic response of high-rise buildings, but the application to long-span structures subjected little researches.The dynamic behaviour of long-span structures is often affected by several effective modes, so the contributions of the high-order modes can not be ignored. Both traditional Pushover Anlaysis (Capacity Spectrum Procedure) and Model Pushover Anaysis were employed to estimate the seismic response of long span structure, and the results were compared to illustrate the effect of high-order modes.The long-span tridimentional arched steel truss in Beidaihe Train Station is taken as a case study in this paper. The methods of CSP, MPA and THA were employed to evaluate the performance of the structures under rare earthquake with Elcentro Wave and Tianjin Wave as earthquake input. The results of the displacement and plastic hinges distribution were compared to verify the feasiblility of pushover analysis. The effect of member buckling on structure seismic behaviour was considered by changing the material constitutive relationship.The study indicates that CSP and MPA evaluate the dynamic displacements and week locations of the long span structure accurately enough to meet the practical application. However, the distribution of the plastic hinges still needs some improvement compared with the results of THA. Considering of member buckling results in more plastic hinges, but has little effect on dynamic displacements. It is also noted that member buckling may cause failure of the structure under strong earthquake and lower the capacity of the earthquake resistance of the structure.