Energy Based Seismic Response And Design Method Of Building Structures

Transmission conversion and absorption(dissipation)of earthquake energy are the fundamental characteristics of the structural seismic response. Not only the analysis and design method based on energy concept can better reflect the whole history and the elastic-plastic performance of the structure under the ground motion, but energy response and energy conversion have definite concept and simple form. It considers the effects of many design factors and has obvious advantage. The analytic method of structural seismic energy responses is increasingly attached importance to the international seismic engineering research, and regarded as development tendency in structural seismic design theory. Calculation procedure using time history analysis method to study structural energy is introduced in details in this paper. Considering seismic input motion parameters and structural dynamic parameters, the varied laws of the distribution of MDOF elastic-plastic structural seismic total input energy between hysteretic energy and damping energy is investigated, also the laws of the storey distribution of the hysteretic energy. It has been found that the damping ratio has a significant influence on the ratio of Eh to Ei .When the damping ratio ξ is 0.02, the value of Eh/Ei. is in the range of 70-80%; ξ= 0.05,Eh /Ei is about 50%;ξ=0.10,Eh/Ei is about 30%. The storey distribution of the hysteretic energy is ladder-shaped pattern, namely, the hysteretic energy hi the bottom is larger than that in the upper stories and the bottom stories are apt to be the weak stories. From the above conclusion, the two-stage design method for MDOF buildings based on energy concept is presented on the basis of current design standards.