Research On Seismic Behavior Of Frame Tied Concrete-filled Steel Tubular Arch Bridge And The Analysis Methods

With its excellent performance, frame tied concrete-filled steel tubular arch bridge is considered to be one of the best structure types for the middle or large span bridges. It is widely used in China, as a country with high probability of earthquake occurrence, studying on the seismic behavior of this bridge type is very necessary and urgent. There are three kinds of seismic analysis methods: response spectrum method, time history method and stochastic vibration method. Response spectrum method and time history method are deterministic analyses, while stochastic vibration method is probabilistic analysis. Stochastic vibration method is based on probability and statistic theories, and it is a more and more prevailing seismic analysis method.Seismic analysis methods and the behavior of frame tied concrete-filled steel tubular arch bridge under earthquake are researched in the paper. Research work of seismic analysis methods is focused on time history method and stochastic vibration method. The following aspects are included in the research work of time history method: determination of damping, principles for choosing earthquake acceleration records used in the time history analysis, methods for solving dynamic equation. And the research on stochastic vibration method is a key point of this paper, it includes:basic nomenclature used in the stochastic vibration method are explained, method for describing stationary random seismic excitation is presented, Clough-Penzien model is adopted to describe the acceleration power spectral density, solution methods for stochastic vibration analysis is profoundly studied. The research work of solution methods for stochastic vibration analysis includes: mode superposition method is deduced all over again, by introducing certain intermediate quantities, the deduction is more precise and easy to understand; in addition, the essence of the pseudo excitation method is disclosed, which is a sparkle of this paper.The behavior of frame tied concrete-filled steel tubular arch bridge under earthquake is studied through the analysis of Xiadian Bridge, which locates in Wuxi. The influence of soil-pile-structure interaction on the seismic response of the bridge is figured out by time history analysis. The effect of geometrical non-linearity and geometrical material coupled non-linearity are studied by means of pushover analysis, during which nodal displacement deviation vector norm is presented to indicate the non-linear behavior of the arch. Response of the bridge subjected to identical support motions is calculated by response spectrum method and stochastic vibration method, but time history method is substituted for response spectrum method when the wave propagation effect is taken into consideration. Results obtained from different methods are compared with each other.