Study On A Similar Analogy Theory-based Seismic Loss Assessment Methodology Of Frame Structures

Traditional seismic vulnerability method which is analyzed with macroscopic influence factors,such as seismic intensity,building time,site classification and so on,is easy to be understood and accepted.However,the influence of microscopic influence factors,such as structural material strength,component dimension and seismic measure to seismic performance cannot be evaluated quantitatively.The results of traditional seismic vulnerability method is just macroscopical and imprecise.Nonlinear numerical analysis-based loss assessment method can get reasonable results,but it appears inefficiency,especially for community construction.RC frame structures are used as examples,similar analogy theory-based seismic loss assessment method is proposed in this paper with similar analogy idea of traditional methods.Structural seismic performances can be evaluated with no need of real structural models calculations,thus the numerical computational efficiency of structural seismic vulnerability could be increased enormously.The essential of structural seismic vulnerability analysis is structural nonlinear analysis,and the element numerical models are the most important part.Three frequently-used elements of nonlinear analysis are simulated,and the accuracy of the elements is analyzed.So the results could lay the foundation for the following work.Macroscopic influence factors change at a scope which are not continuous parameters,although they are easy to be determined.Taking RC frame structures as examples,the idea that microcosmic structural influence factors are used as analogy parameters is proposed in this paper.The main viewpoints of this idea are that the similar degree of two buildings is measured with weighted Hamming distance,and weight coefficients of microcosmic structural influence factors are calculated by analytical hierarchy process.The relationship between the maximum displacement of different seismic intensities and the structural parameters is obtained by the capability spectrum method with single analysis of each structural parameter,and the k value can be determined statistically.The proposed method and the finite element method are implemented to three groups of representative structures respectively,and the precision and applicability of the proposed method are validated.Structural modeling uncertainties which includes dead load,live load,concrete compressive strength,rebar yield strength,rebar elasticity modulus and damping coefficient and their influence on structural seismic assessment are studied with the first order second moment method(FOSM).The result of this research suggests that modeling uncertainties is negligible in the range of low seismic intensities,but the influence of uncertainty increases with increasing earthquake intensity.So modeling uncertainties should be considered in high seismic intensities or the fourth limit state.