Research On Nonlinear Seismic Analysis Method For Reinforced Concrete Bridges

Earthquake is a common and severe destruction on earth’s natural disasters. When the earthquake struck it will release humerous energy and thus cause the destruction of structures and facilities on the ground, seriously affect the national economy and people’s normal daily life. We are in a rapid times of quick development of social economy, science and technology. Throughout the world, a large number of population distribute in developed city. And bridge structure is the lifeline of urban’s development, once the bridge destroyed in the earthquake, the resulting consequences will be very serious.Under seismic load, the most part of the bridge pier has entered the stage of elastic-plastic, so it is necessary to study the nonlinear behavior of the bridge structure. Elastic-plastic analysis of the structure of the bridge is a hot problem in recent years.Domestic and foreign experts and scholars are exploring it all the time. Basic on the study of nonlinear beam-column elements is currently follow the method of the theory and numerical model analysis. Although the bridge structure elastic-plastic analysis method is varied, around the beam- column elastic-plastic finite element analysis theory is still the core of the research structure elastic-plastic analysis method. At home and abroad, the study of structural elastoplastic seismic analysis method is mainly based on two aspects, the concentration of the plastic hinge nonlinear beam-column units and fiber beam- column of reinforced concrete elastoplastic algorithm.Although around the nonlinear beam-column elements and reinforced concrete plastic hinge fiber beam-column elements has been in-depth study, and many countries also developed many simplified calculation method about the bridges elastoplastic seismic analysis. So far, there is no study about algorithms on bridge elastoplastic seismic calculation results and the influence of the difference. There are two methods to research the bridge seismic dynamic performance evaluation, the method of capacity spectrum which is based on Pushover and the method of time history analysis. But few studies have compared the similarities and differences between the two methods.This topic in combination with the current situation of domestic and foreign related research, through a lot of simulation calculation of ordinary reinforced concrete bridge of elastic-plastic seismic analysis method is analyzed. The topic depend on finite element software Midas/Civil, firstly through the static nonlinear analysis method(i.e., pushover) systematically research main parameters which affecting the seismic behavior of RC bridge pier. Then through the establishment of pier of plastic hinge model, the fiber element model and the equivalent linear elastic analysis method were analyzed. Summarizes the characteristics and differences of the three kinds methods. Finally compare the RC double column pier plastic hinge model and the fiber element model of each parameter value of seismic performance.Then contrast and analyze the seismic performance evaluation method of RC double column pier by the capacity spectrum method which base on pushover and the nonlinear dynamic time history method. The main parts of this topic are as follows:①Through consulting a large number of data, especially the bridge seismic damage data in recent 30 years, has introduced the research background of this topic, the research status at home and abroad, and also the research significance and the main content;②The seismic response analysis methods of the bridge are summarized in seismic demand and structural energy dissipation, and then the concept of bridge structure ductility is induced;③With finite element software Midas/Civil by the method of static nonlinear analysis systematically research the seismic performance of RC bridge and ductility level analysis, and discuss the various main affecting parameters on the seismic performance of RC bridge pier and ductility level;④The rules of RC pier whole bridge model is set up, respectively consider factors on plastic hinge model, fiber element model and the equivalent linear elastic analysis method by the IDA analysis method;⑤Establish RC piers of continuous curved girder bridge concentrated of the plastic hinge model and the fiber element model, and test the equivalent linear elastic method for the applicability of the irregular bridge seismic on designation and calculation;⑥Finally compare the RC double column pier plastic hinge model and the fiber element model of each parameter value of seismic performance.Then contrast and analyze the seismic performance evaluation method of RC double column pier by the capacity spectrum method which base on pushover and the nonlinear dynamic time history method.