The Fragility Analysis And Aplication Of RC Frame Structure Based On Main Shock-aftershock Sequence-type Ground Motions

One earthquake always happens accompanied by the sequence ofaftershocks or earthquake clusters, and in general structures also can experiencethe main shock and numbers of aftershocks. In such cases, structures will emergedamage after the effect of main shock and will appear more damage when theaftershocks affect following the main shock. Such will make structures can’tcontinue to use or even collapse, which will cause serious earthquake losses.However, criterions concluding our country and other countries in the worldaren’t considered the influence of the main shock and aftershocks sequence, sothe researches of the effects of the main shock and aftershocks sequence aremeaningful. The seismic vulnerability analysis of structures is used to study theprobability that the damage of structures exceed one failure state with thefunction of the earthquake. It belongs to one part of the seismic risk analysis andcan be used in estimating earthquake losses. At present the seismic vulnerabilityresearch with RC structures mainly uses a single main shock without theaftershocks, so this article will systematically analyze the vulnerability analysisof RC structure based on the action of main shock-aftershock sequence-typeground motions. The main contents of this paper are as follows:(1) One RC frame with six floors is designed in accordance with the Chinesebuilding codes and is used the improved Park-Ang damage index to calculate thedamage. In addition the algorithm of various parameters in the improvedPark-Ang damage index are particularly introduced.(2) Choose100actual records of the main shock–aftershocks sequence anduse them for the dynamic time-history analysis to the RC structure. And nextrecord the reaction and calculate the improved Park-Ang damage index. Finallyget the statistical result of the improved Park-Ang damage index andvulnerability curves based on two sequences of the earthquake ground motion.(3) Make use of the vulnerability curves. Give the seismic hazard analysis toone district and combine with the vulnerability analysis results to get theprobability when the structure is in one damage state. Last calculate theearthquake losses using the above results.