Study Of Response Spectrum Method For Non-proportionally Damped Islated Structures And Dynamic Analysis Of Lateral-torsional Coupled Vibration

The base isolation is a kind of passive control system, which is applied in the field of civil engineering widely and sophisticatedly. The isolation layer of the system is so different from the material of upper structure in natural that the damping matrix in the motion equation takes on obvious non-proportionality. And the non-proportional characteristic of the isolated system is described in Rayleigh's damping theory of sub-structures in this thesis, which is also used to set up lateral-tortion coupled motion equation of eccentricity non-proportional damping isolated structure. The influence of stiffness eccentricity, mass eccentricity and isolator damp on the dynamics response of non-proportional damping isolation structure of MDOF is analysed by time-history method.Due to non-proportionality damp, the traditional real mode superposition method can not fit to resolve seismic response of the base-isolated system. A kind of simplified and practical real mode superposition method is established, which is based on the mode superposition method of MDOF non-proportional damping isolated system and by the means of cutting the influence of couple item of low rank modes damp on the same of high rank modes damp. And the study results show that the computation method put forward in the thesis can meet accuracy commands of engineering design.In the light of low credence statistically and complex calculation of current time-history method, the simplified real mode superposition method in this thesis will be combined with ration vibration theory, and a way based on displacement response spectrum and nudged by SRSS method to estimate inter-layer displacement and inter-layer shearing force is found. Three samples of engineering analysis have tested that displacement response spectrum method is a simplified way and can meet accuracy commands of engineering design.