Research On Near-field Earthquake Collapse Maximum Ratio Of K Type Steel Eccentrically Braced Frame Based On Maximum Effect Cyclic Energy Spectrum

In recent years,the earthquake brought to human damage caused the wide attention of the society,the current specification based on the strength of the design method can not withstand the test of a strong earthquake.Based on the characteristic of structure seismic design concept arises at the historic moment.FuMing Cai[2] introduces the maximum effect cyclic energy spectrum,and proposes a performance-based seismic design method of K type steel eccentrically braced frame under near-field earthquake according to the energy balance equation.Ten-story and fifteen-story K type steel eccentrically braced frames were designed using the method above.Those two structural calculation models were set up in the ABAQUS.This paper uses the method of IDA,which was combined with the seismic collapse assessment principle and seismic database in FEMA P695,to analyze the collapse maximum ratio and structure fragility of these two structures.The collapse criteria and threshold limitations for collapse assessment was settled by the author.The results of seismic collapse analysis show that the collapse maximum ratio of that two structures,which was gotten from IDA curves,can meet the individual structure seismic collapse security requirement and group structure seismic collapse of security requirements.Taking the advantage of Spectral Shape Factor(SSF)into consideration,structure collapse resistant safety reserve become bigger.This proves that the method of K type steel eccentrically braced frame in literature[2] which is based on maximum effect cyclic energy spectrum can meet the requirements of near-field earthquake collapse maximum ratio.According to structural fragility curve,the collapse probability of two structures under severe earthquake is zero.From which also illustrate the structures designed by the method of literature[2] have super performance under severe earthquake.The reasonably and reliability of this seismic design method which was based on the maximum effect cyclic energy is verified by the results of the analysis collapse analysis.This paper also provides technical reserves in the establishment of structure seismic design code.