SIMULATION OF EARTHQUAKE GROUND MOTIONS COMPATIBLEWITH MULTI-DAMPING-RATIO-SPECTRA BASED ON GENETICALGORITHMS

摘要

The artificial seismic waves used in seismic design should satisfy multi-damping-ratio-spectra simulationrequirements. Present simulation methods of the ground motions are suitable for single-damping-ratiospectrumsimulation, but the simulation precision is not satisfactory for multi-damping-ratio-spectrasimulation. In fact, there should be different design spectra corresponding with the structures of differentdamping ratios, the new Code for Seismic Design for Buildings, GB50011-2001, of China has providedcorresponding spectra for structures with different damping ratios. Obviously, the artificial groundmotions used for structural time history analysis should be well coincided with multi-damping-ratiospectra.Based on the comparison of the conventional algorithms with the multi-objective optimization and geneticalgorithms, a method for the simulation of multi-damping-ratio-spectra is proposed in this paper, whichcombines the multi-objective optimization algorithms and genetic algorithms. The program proposed isexamined by several examples including actual earthquake records and artificial seismic waves. Thesimulation precision of the method is checked by many aspects such as intensity, spectra, and parametersof ground motion. The precision of simulation of ground motions compatible with multi-damping-ratiospectrahas been improved comparing with the conditional one. The Pareto optimal solution set can beobtained conveniently which is difficult by the conditional one. The results show that the method hasmuch more advantages over the traditional methods and it's adequate to meet the needs of simulation ofground motions compatible with multi-damping-ratio-spectra in seismic design.