Study On Reliability Of Concrete Simply Supported Bridge In The Life Cycle

Based on the life cycle cost，the paper analyze all sorts of random factors whichhave effect on the simply-supported bridge degradation and set up the time-variantreliability calculation function of concrete simply-supported bridge，and the functionwould be analyzed by ANSYS based on the probability design of finite element．Thenthe article figure out failure probability and reliability value as a sample，and predictthe curve of time-variant reliability by the grey prediction model．AT last thereliability indexes of the beam bridge expected life is obtained，the specific researchwork are described in the following：1) By refering to large quantity literatures of home and abroad，state the basicconcepts and method of reliability，introduce the principle and methond of systemreliability，analysis and contrast kinds of method，and select the conformableanalytical method of time-variant reliability．2) According to the researched environment of the beam bridge，the paperanalyse various factors of the simply-supported bridge which affect the structuralresistance in life cycle：as climate condition，carbonization corrosion of concrete，chlorine damage in reinforced，reinforced strength，concrete strength，bondingstrength with rebar and concrete etc，and these factors are analysed separately．Methodabout the time-varying functions of influence factors are proposed， analyzesinfluence of method on the force attenuation of bridge structure， load model andforce attenuation model of bridge structure are established based on multi-factors．Thetime-variant reliability functionn in the life cycle is formed．3) the bridge degradation simulation is presented based on the finite element，of，a finite element model and the static analysis is established by Ansys．Monte carlocalculation by finite element analysis and probabilistic design of Ansys Imitation oftime-variant resistance is took action on concrete simply-supported bridge model．Theengineering example is calculated by three kinds of design calculation method．Thevarious methods are verified by result of calculation，and the applicable scope ofvarious methods is confirmed．Failure probability of structure is presented by the finite element analysis for probability design．4) Grey theory is put into reliability prediction，and finite element calculationconduct probability samples．Grey model is set up by grey theory．Mathematicalprogram which predict failure probability and time-varying curve of reliability isbuilt，and accuracy about the grey prediction model for forecasting reliability isverified．5) In the life cycle，according to the characteristics of concrete simply-supportedbridge，based on the reliability analysis process of the life cycle，the paper analyze andcalculat design example of concrete simply-supported bridge by concrete calculationprogram，verifying feasibility on the process of reliability analysis，Calculating resultsby the different initial design parameters．Finally according to reliability curve，formula and the weather condition， the expected reliability index of concretesimply-supported bridge in50years is calculated．...