Study Of Seismic Responses Of Multi-tower High-rise Buildings With Enlarged Base Under Earthquake

The multi-function is becoming the development trend of high-rise buildings day by day, and in order to meet the diversified demands of the structural function and architectural appearance, a large number of high-rise buildings with complicated size are emerging constantly. Among them multi-tower high-rise buildings linked by spatial corridors and with enlarged base at the bottom (MHBSCEB) is a typical one. Compared with the common high-rise building, the mode shapes of MHBSCEB are more complicated, the influence of high-order mode shapes on the internal force is more remarkable, and the effect of torsion vibration is also large. Supported by the Research Funds of Wuhan Construction Department (No. 2005-18), this thesis is aimed to analyze dynamic characteristics and responses of MHBSCEB due to earthquake by theoretical and numerical studies. Firstly, the types of MHBSCEB are introduced in this thesis, and the computing models for different components and the dynamic analytical models for MHBSCEB are presented. Especially, the seven kinds of basic mode shapes of symmetrical three-tower high-rise building with enlarged base are got. The dynamic characteristics and response of MHBSCEB due to earthquake are studied theoretically. Secondly, in the thesis the numerical analysis of the dynamic characteristics of multi-tower high-rise buildings with enlarged base (MHBEB) and dynamic response due to earthquake is carried out by using 13 computing cases from the Sheng Taosha Mansion in Wuhan and other two numerical examples. A lot of valuable conclusions are got in the following aspects: the basic mode shapes of the structure, the participation coefficients of the mode shapes, the characteristics of the dynamic response of the structure under earthquake, the choice principle for the mode shapes'number for MHBEB while the earthquake effect is analyzed by the mode decomposition method, some characteristics of the asymmetrical MHBEB and the influence of the asymmetrical degree on the response of the whole structure and the towers. Finally, the influence of the mass, the stiffness, the connecting form, the location of the special link and the number of the layer of the special link on the dynamic characteristic and response of MHBSCEB subjected to earthquake are discussed in the thesis. The numerical analysis is carried out by using 3 computing cases and some conclusions are also got. This thesis suggests that the special link should be set in the upper place than the middle of the tower. In this case: the bottom shearing force and torsion moment of the structure are in the minimum range, the bottom moment of the structure are in the middle range, and the displacement of the structure is not too big; Only when the earthquake function is in the X direction, the shearing force and moment of the special link in the vertical plane are relatively big, otherwise, the internal force is in the smaller range.