R-μ Principle In Seismic Design And Overstrength Character Analysis Of Typical Reinforced Concrete Frame Structures

The dominant seismic design method in current seismic design codes of different countries is still the conventional seismic design method based on elastic response spectra theory and R-μprinciple. In this method, the reference earthquake design level is reduced to relatively lower earthquake level adopted by design through force reduction factor R, and the corresponding capacity design measures are adopted to ensure the response demand of structures under strong earthquakes doesn't exceed the response capacity.However, the recently revised seismic design codes IBC 2003 of USA and NBCC 2005 of Canada reveal a trend of increasing reference earthquake design level from earthquake level with a recurrence period of 475 years to anticipated maximum earthquake level so as to provide a more uniform margin against collapse. This makes that R-μrelations and overstrength character of redundant structures corresponding to anticipated maximum earthquake level should be further studied.Therefore, the main research work finished preliminarily in this thesis is as follows:①Summary and analysis of the chief research findings of R-μ-T relations for single-degree-of-freedom inelastic systems so far finished.②Summary and commentary of the main research findings of R-μrelations and overstrength character of redundant structures.③Summary and comparison of specific measures reflecting R-μprinciple and overstrength character in seismic design codes of different countries.④Overstrength character analysis of five typical frames, which separately locate in intensity zonation 0.1g, 0.15g, 0.2g, 0.3g and 0.4g, through dynamic pushover analysis, and discussions of the analysis results.From the research work stated above, the main conclusions can be drawn as follows:①The main research findings of R-μrelations of single-degree-of-freedom and multi-degree-of-freedom inelastic systems are consistent. It should be admitted that R-μprinciple is the fundamental principle to ensure seismic performance of structures and must be followed when load combinations including earthquake action control the design of structures. The flaw of current Chinese codes which is inconsistent with R-μprinciple is pressing for remedy.②If the anticipated maximum earthquake level are determined as reference earthquake design level, the force reduction factor R of actual structures may include at...