Pseudo-elastic Plasticity Method Research Of Frame Structure Based On The Energy Equivalence Principle Of Component

The maximum plastic-elastic displacement is the main aspect of structural performance evaluation in the structure design. To grasp the max plastic-elastic storey drift of structures has great significance for the engineering. The general elastic analysis method is adopted in structure anti-seismic design in many countries, which satisfy the level that no collapsing with rare earthquake by seismic fortification measures. The method is qualitative. And elastic-plastic analysis is more difficult and complex. So looking for a simple but effective way to solve the structural inelastic displacement is one of the hotspots in the academic and the engineering fields currently. In basis of theoretical calculation and analysis, a pseudo-elastic plasticity method which gets the structural plastic-elastic displacement by elastic analysis is proposed in this paper. And the contents are as follows:1) Calculate the yield moment and curvature of beams and columns by Chinese Codes and XTRACT separately. The results calculated by .Chinese Codes are modified according to the ones calculated by XTRACT. For column, the modified factor of yield moment is constant, and the modified factor of yield curvature is relevant to the axial compressive ratio. For beam, the modified factor of yield moment and curvature are both constants. With the modified factor, a table for calculating the yield moment and curvature is summarized.2) A method to reduce stiffness of the components based on the energy equivalence principle is presented in this paper. With the maximum elastic moment of component under rare earthquake and the calculation table mentioned above, stiffness reduction factor could be solved by introducing a modified factorλ. Thus, pseudo-elastic plasticity method is proposed: make elastic time history analysis on the structures with stiffness reduced, and the elastic displacement of the analysis results could be equivalent to the structural plastic-elastic displacement.3) The pseudo-elastic plasticity method is realized through program. Nine model of RC frame under 8 agree rare earthquake are analyzed with the program. By comparing storey drifts between plastic-elastic analysis and elastic analysis, validity of the method is proved and rules of reducing stiffness are summarized.