Nonlinear Seismic Reliability And Fragility Analysis Of RC Structures

Nonlinear seismic reliability and seismic fragility analysis for civil engineering structures have been a very popular research direction in both structural engineering and earthquake engineering community. Specifically, the seismic reliability analysis of reinforced concrete structures has been a difficult problem due to the complex constitutitive equations. This thesis presents a thorough study on the nonlinear seismic reliability and seismic fragility problems of RC elements and frame structures. The main contents are as follows:(1) The nonlinear behavior of reinforced concrete element is analyzed by using the fiber models. Based on the results of nonlinear member analysis, the Monte Carlo simulation method is adopted to calculate the reliability of RC element. The iso-reliability contours are plotted for typical compressed and bended members in load space. The influence of many factors, such as concrete strength, the ratio of reinforcement and the ratio of stirrup on iso-reliability contours are considered.(2) Taking OpenSees as the computing platform, a nonlinear finite element analysis model for RC frame structures is established, and then, the nonlinear finite element response sensitivity analysis is performed on the levels of global structure, elements, sections and material. By using the finite element reliability methods (FERM) based on FORM, SORM and IS, the nonlinear static seismic reliability index and their corresponding failure probabilities are obtained for both strength and deformation limit states of RC frame structures when considering the provisions of the current design codes. Four probabilistic importance measures are introduced, and then, the importance of random variables are analyzed, and the most importance and unimportant variables are ranked according to their importance measures.(3) Both global and local seismic fragility problems are studied respectively. The method of global seismic fragility analysis based on reliability and performance as well as local seismic fragility analysis based on reliability and sensitivity is put forward. Taking the displacement response as the performance index of structures, the global seismic fragility analysis is conducted on RC...