The Study Of Application Research Of The Hysteretic Energy Dissipation-based Push-over Analysis Method.

Bridges hold the key positions in transportation system. Once important bridges are destroyed in earthquakes, there will be great difficulties for the emergency managements and bridges restoration. By evaluating the seismic capacity of existing bridges, the destruction process of every member of the bridge structure may be grasped wholly, and the weak positions of the structure may be found so that the bridge will be strengthened before earthquakes. Estimation of the bridges offers a basement for the reliability analysis, damage assessment and retrofit of the bridge structures and the emergency responses after earthquake. It is one of the basic works for earthquake prevention and disaster reduction in the city areas.Presently, seismic design has been shifted from force-based design to performance-based design or displacement-based design. As the development trend of earthquake engineering, the basic ideal of performance-based seismic design will be used as the design criterion and applied to the present projects. This dissertation focused on the Pushover analysis method on the basic of summarizing concerned internal and overseas theory and method, and an evaluation method of seismic capacity of bridge structures is developed based on the adaptive hysteretic energy dissipation spectra-based push-over analysis method, which was validated by some examples. As an important tool of the performance-based design, improving the computation precision of Pushover analysis and making a probability investigation to the analysis results are the research hotspots. The research contents developed mainly in the thesis are as follows:1. The thesis puts forward the adaptive hysteretic energy dissipation-based push-over analysis method. Many collected seismic waves are divided into groups on the basis of the field site etc and the corresponding hysteretic energy dissipation spectra are established. Based on the modal pushover analysis given by Chopra and the energy-based drift given by Aschheim, the energy-based drift is imported into the Pushover analysis with hysteretic energy spectra. In the thesis, the pier members are simulated with pole model. Fortran90 is used to program for hysteretic energy spectra. And SAP2000 is used for the Pushover analysis of piers. Under the help of hysteretic energy spectra and step-by-step analysis method, we can improve conventional mode ability curves. Lastly, some examples demonstrate that the feasibility of the method in the thesis.2. In conventional MPA method, in every mode, the horizontal load is equal to the product of the mass and the elastic mode victor, as they do believe that the figure vector holds the line, in every mode, in spite of the size of the distortion of the structure. But, in this text, in the improved MPA method, the figure vector holds the line with the current pier displacement vector accordingly the load is equal to the product of the current displacement victor and the mass. Only in this way, can the Pushover method coincide with the fact. In this paper, the improved ability curve is used in mode combination, with consideration of the redistribution of inertia forces after structural yielding, which is used to compare with the result of the conventional ability curve.