Study On The Reliability Analysis Of Aseismic Building Structure With Intermediate State And Failure Dependence

The reliability analysis of building structure is the important measure to assure building user's life and property security. But conventional reliability theory is based on Sutra probability hypotheses and two state hypotheses, it divides the working state of unit and system into "security" and "failure" second grade, which take "mutation" 'mode from security to failure. To a large number of building structure, the theory incompletely accords with the actual instance, because the working state of structure changes gradually from security to failure. There is a intermediate state in the structure from fully meeting the requirement of function to shorn of function(losing it), namely it can be under the graceful degradation though it was distressed. Therefore this article put forward that structures and systems should possess "security-intermediary-failure" third class working mode.In this paper, we establish the method on degree of reliability analysis according to three stage fortification standard stated by aseismic design code, based on principle that structure should possess " safety - intermediate - failure " three stage working modal, learning once second moment farad to determine structural reliability index and failure probability, and explore degree of reliability analytical approach of aseismic structure with intermediate state AND failure dependence. The main content is as follows:(1) Based on Sutra probability hypotheses and two condition hypotheses, we put forward the viewpoint about intermediate state, considering that structures all possess three kinds of working position of safety, intermediate, failure. Reliability analysis consequence is to determine safety probability PR , intermediate probability PM and failure probability PF, then they join up to constitute reliabilityvector [PR,PM,PF](2) Making use of operators of S -union and T -intersection of stochastic event, we establish calculation method and step for reliability vector of serial system and parallel system with intermediate state. The failure-dependence parameter λ in the operators of S -union and T -intersection of stochastic event are given reasonably.(3) According to lineation stochastic programming, an effective algorithm is put forward for searching structure principal failure mode. In structural reliability analyses, random line complementation function equation should be solved andtime base variation should be selected to carry out Gaussian elimination, thus, ray solution about structure changed mechanism can be obtained and we can get structure principally failure mode.(4)Adopting algorithm of random event' conditional probability and introducing condition association coefficient of failure mode can reflect failure dependence of structure. Through large earthquake damage survey, we establish approximate treatment means on essential condition association coefficient of the same project.(5) Analyzing degree of reliability when frame structure suffer earthquake effect, we can figure out its reliability vector and compare with traditional degree of reliability analytical method.