基于可靠性分析的已建立交桥抗震加固方法研究

In this subject, some problems of overpass structure in earthquake are deeply studied from standpoint of theory and practice. The reliability analysis method of verpass structure with uncertain arameter has been discussed. The earthquake esponse problem in multi-joint excitations and the damage criterion problem of overpass structure are studied. In addition, the system earthquake-resistant optimum analysis methods of overpass structure have been done carefully. As a result, the methods presented in the subject can be applied to several aspects, such as overpass structure design, retrofit and so on. The main new ideas in the subject can be summarized as follows: 1. The reliability analysis method of overpass structure is proposed by considering uncertainties of parameters and the effects of friction force at movable supports. Generally, the characters of structure system (mass, stiffness, damping and strength) and random loads characters (frequency composition and duration time) are assumed to be certain in traditional structure analysis, but these parameters are uncertain and variable in practical engineering. The earthquake-resistant reliability method to analyze the pier of overpass structure based on the Fast Integration Method is studied. And the earthquake-resistant reliability method to analyze the concrete beam of overpass structure according to a simplified limit analysis approach by considering the effects of friction at movable supports is also discussed.2. In this subject, the analysis mode of overpass structure is proposed by considering unit modes of column, beam and friction force at movable supports. The equilibrium equation in multi-joint excitations and the damage criterion of overpass structure are built. Finally, the seismic response analysis of overpass structure in multi-joint excitations is studies. The earthquake damage process of overpass structure is also displayed, and the analysis methods of overpass structure can be employed in future studies deeply.3．The earthquake-resistant optimum retrofit ideas are presented for overpass structure based on reliability at two given constraint condition levels of overpass structure engineering system. These methods may be applied to some aspects, such as earthquake-resistant retrofit and the earthquake-resistant decision for practical overpass structure.

根据积函数极值理论，推导立交桥墩刚度已知，其梁、板刚度不明时的上限地震荷载，利用一次二阶矩法，建立其局部单元在加固前的可靠性分析方法；编制程序，计算其在加固前的可靠度。根据拉格朗日乘子法，建立在立交桥系统结构整体可靠度约束条件和加固总投资约束下，立交桥的加固优化方法。为立交桥的抗震加固提供理论依据。