Theory And Application Of Push-over Procedure

The earthquake is one of the most threatening natural disasters to the humanity. As the nation of the most centralized continental earthquake, the intensity and the frequency of earthquake in our country is the first place in globe. For many years, people have devoted to developing and consummating the theory of earthquake resistance and the engineering measure. Along with the progressing of social productive level, several big earthquakes occurred in recent years at the domestic and foreign presented the characteristic of small casualties and high economic loss. On the one hand, this fact tells that the earthquake resistance ability and the correlation discipline has been developed to a high level, at least may guarantee the life safety, on the other hand, also points out the future target is guarantee of property safety, under the premise of life safety. Under such a circumstance, great efforts have been done by governments, organizations and researchers around the world to meet this challenge, performance-based concept was proposed, its basic goal is the predictable seismic performance of engineering construction, the owners and the designers' choice and realization of different performance capability for the various construction projects. The principal realization method of performance-based seismic design (PBSD) is the displacement-based seismic design (DBSD), so, due to the advantage of concise, intuitionistic and informative, the push-over method whose original intention is to establish a fast appraisal way for earthquake resistance performance of structures under major shock, obtained the focus and developments, along with the widely acceptance of PBSD and DBSD in 90's. Several basic issues and the state-of-the-art of PBSD and DBSD, the origin and developing process of push-over method, as well as the commonly used Capacity Spectrum Method (CSM, ATC 40) and the Non-linear Static Procedure (NSP, FEMA 273) and some important parameters were detailed in first chapter.As a seismic performance assesment method without rigorous theoritical foudation, the veracity (feasibility) of push-over procedure basically depends on whether its computational result could be consistent with or approach to other reliable methods. In many kinds of seismic experiments, shaking table test may reflect the dynamic speciality even damage mechanism of structures under the specific earthquake excitation, therefore is widely adopted in engineering practice and research. The results of a model shaking table test is usedin this paper for comparative research of push-over procedure. The test object is a modified prefabricated prestressed concrete skeleton structure (IMS system) which is intend for the modernization reconstruction and improvement of minority civilian dwelling houses in Yunnan Province. Some important researches since the introducion of this system into China in 1977 were briefed in this chapter, and for the purpose of studying the dynamic speciality and seismic capacity of IMS system, a shaking table test of a 1/2.7 scaled model was conducted. Based on the test results, the nonlinear time history dynamic analysis was performed, and a new approach for simulation of nonliear properties of reinforced concrete (RC) beams and columns was attempted, i.e., the moment-curvature relationship of RC rods was calculated firstly by section analysis, then the RC rods were taken as the equivalent homogenization material, and its elasto-plastic stress-strain law was transformed from the moment-curvature relationship in virtue of some assumption, so the restoring force properties of RC rods could be reproduced indirectly. The merit of such a technique is that some general purpose finite element analysis system could be used plumply for RC components. In concert with the analysis of the model, some problems such as the selection of earthquake records, numerical solution of dynamic equations are disscussed and analyzed. The results of time history analysis approximately tally with test datum, so it could be taken as basis for further analysis. In o...