| The response of the structures will be translational as well as torsional because of the asymmetric-plan that caused by the irregular distribution of the mass and the stiffness so that the center of the inertia force and the resistant force will be unlined. The torsional coupling response will induce the structure's dimensional effects that are not easy to be resolved in the two dimensions. Furthermore, there are some difficulties not only in the experiment research but also in the computer analysis, especially for the dynamic non-linear analysis, In order to improve the seismic design, the research in this field should be lucubrating. Nowadays, the regulation of the torsionally design in the world codes are mainly based on the experiments of the single element or the vibration-platform model; many guidelines of the structure's arrangements are base on the earthquake experiences and the quantitative analysis bases are scarce. So it's necessary and important to research the asymmetric-plan structures' earthquake response in order to improve the code for the seismic design.This dissertation is a part of the national science foundation subject "Effects of Torsion on Nonlinear Seismic Response of Structures"(the code number: 59978055). The earthquake responses of the asymmetric-plan structure are researched and the main factors that influencing the structure's response are established. The influences of the earthquake type and the earthquake input in two directions are also researched. The effectiveness of regulation for the irregular RC frames in the code for the seismic design (GB50011-2001) is discussed using the flexibility-based fiber-models beam-column elements in the 3D nonlinear analysis program. According to those, the main results are gained.1. Based on the infinite element analysis program (FEAP 7.3), two 3D models are programmed, which are the inter-storey model used to analyze the factors and beam-column element based on the fiber models for irregular buildings' dynamic experiments. Otherwise, the functions of the earthquake analysis are appended in this program.2. The factors influencing the one-storey asymmetric building are extensively resolved and analyzed. And those influencing the multi-asymmetric building's factors are resolved using the model analysis. The influence of the strength eccentricity during the nonlinear response is researched, and the seismic fortification measure controlling thenonlinear twist is presented. The effectiveness of this measure is analyzed using the fiber models.3. According to the classifying of the earthquake records, the influencing degree of different ground motions to the eccentric buildings is researched. The response of the irregular RC frame under the strong ground motions is analyzed using the fiber models.4. The response of multi-storey regularly asymmetric building excited by two directions earthquake is researched. And the torsional coupling response influenced by the strength eccentricity is discussed. The response of the RC frame excited by two directions earthquake is simulated using fiber models.5. The frames in different site are designed, and the response under different seismic fortification intensity is simulated using the fiber models beam-column elements. Some preliminary results are gained and the effectiveness of the regulations in the seismic code is discussed.The research of the asymmetric-plan building under the earthquake is one of the difficult points in the seismic fortification field. The simulation of the RC frames designed according to the seismic code is very useful to improve the design method and reduce the earthquake calamity. Thus the study of this dissertation has not only scientific valve in theory but also has applicable value in engineering extensively.
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