| The effect of earthquake on structure is the process of energy input,transformation and dissipation.When the energy dissipation capacity of the structure is greater than earthquake input energy,the structure is safe,and vice versa.Input energy of near-fault earthquake on the structure in a very short period of time can lead to instant failure of the structure.Near-fault seismic pulse characteristics shows it is not reasonable to regard cumulative input energy of ground motion as a basis for design for structure under near-fault earthquake.In order to reflect the near-fault pulse effect,performance-based seismic design method of moment-resisting steel frame using maximum effect cyclic energy(MECE)spectrum is proposed,according to the principle that structure of one-way pushover dissipation energy is greater than or equal to the input energy.This method reflects the balance between pulse input energy and structural dissipation energy,simple and practical.Two moment-resisting steel frame(three-story,three-span and five-story,three-span)was designed based on this new design method and seismic behavior was evaluated by pushover analysis by SAP2000 and nonlinear time history method by ABAQUS.The yield mechanism of steel frames,yielding displacement and base shear was got by Pushover analysis.10 near-fault earthquake ground motion records are selected for each frame.Failure modes,displacement and relative angle along the height,maximum effective hysteretic energy and its distribution under near-fault earthquake was got by history analysis.The analytical results show that the moment-resisting steel frame structure exhibits the ideal progressively developed plastic mechanism;the maximum average drift of moment-resisting steel frame can satisfy the deformation requirement of Chinese seismic code under frequent and rare earthquake levels,and hysteretic energy distribution in component and story is reasonable.The reliability of this design method are verified. |
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