Energy-based Seismic Design Method In Seismic Evaluation Of Tall Buiding Structures

Presently, the seismic design has been shifted from force-based design to performance-based design. The concept of the energy is clear and can reflect the strength and spectra characteristic of the earthquake perfectly, especially the duration of the earthquake brought the general effects of damage to structures, and can lean the inelastic deformation process under the earthquake from the input and hysteric energy, so the energy method is considered an important developing direction of improving traditional resisting earthquake methods.Researchers in and abroad studied the energy-based analysis method and gained elementary achievements. But there were some committed technical puzzles expected to be solved and completed. An earthquake shaking table model was established by taking the Wuhan ShiMao JinXiu Changjiang A2 Block Building 1 unit 3 as an example, rests on the similarity theory and the structure static and dynamic performance equivalent principle; completed the earthquake excition load and the test project design, researched energy-based analysis method and got some conclusions asfollows:1.The contribution of three element factors of earthquake motion should be considered when selecting the inputted seismic wave in analyzing the structural energy.2.The calculation formulas of multi-degree of freedom system energy response under seismic loads are deduced, and the corresponding program is edited. The energy response of the single degree of freedom system is also calculated.3.The relation between energy demand of elastic MDOF(multi-degree of freedom) and elastic SDOF (single degree of freedom) systems is derived through model expansion method. The research results indicate that input energy of elastic N degrees of freedom system can be expressed as a linear combination of N elastic SDOF systems. The coefficients depend on the distribution of mass and stiffness of MDOF system. Investigation of two examples excited by Taft ground motion shows that reasonable results is given by the proposed method.4.The article raised the overall structure of the input to the simplified formula. Based on the seismic energy formula of multiple energy of freedom systom, total input seismic energy, hysteretic dissipated energy and damping energy can be obtained. It is shown that seismic input motion parameters and structural dynamic parameters have great effects on the total input seismic energy. 5.At last, structure damage is estimated by the Park- Ang damage model, and it is shown that the energy response is useful in seismic response and evaluation of strcture damage. And it is feasible that overall damage is evaluated with damage index of D.