Performance Assessment Of Existing Concrete Bridge

With the rapid development of our economy, the reliability of existing reinforcedconcrete bridges is increasingly becoming a universal engineering community concernsand problems to be solved, and how to assess the reinforced concrete bridge in serviceaccurately and reasonably can not only forecast unknown bridge accident, and also helphighway management department to make reasonable maintenance decisions. It takestwo existing reinforced concreted bridge as examples in this paper, by establishing areliable indicator of reinforced concrete bridge division principle, preliminary exploringthe division method for the reliable indicators of the reinforced concrete bridge and thenew assessment method for reinforced concrete bridge. The main contents are asfollows:1, using the basic principles of calibration,improve the grading standards ofexisting literature on reliable indicators of concrete bridges, it transform lower rate ofbearing capacity of the "Highway Bridge Maintenance Specification"(JTG H11-2004)into reliable indicator which able to reflect the structural load effects and resistancereliable, using JC method compile MATALB procedures, the reliable indicatorconsidered different load combinations, different car running, different vehicle loadeffects and the proportion of dead load effect, brittle fracture and ductile fracture and soon.Through the reliable indicator reduction rate under circumstance of differentcapacity reduction,using this rate multiplied by "Highway Engineering StructuralReliability Design of uniform standards"(GB/T50283-1999) provides a reliableindicator of the goal, which get the critical level for dividing a reliable indicator of thebridge. The division level of security of bridge structural members through as acomprehensive assessment of the bridge system security level basis.2, combined with random variable statistics of the existing concrete bridge, takeadvantages of the current reliability study response surface method (RSM), Monte Carlo(MCS), JC method respective together, forming hybrid algorithm. The PDS module ofANSYS applied response surface method and Monte Carlo method for reliabilityanalysis of the structure, at last applied JC method compled Matlab program to calculatereliable indicator of the structure, it established performance function accord to yieldstrength of steel and concrete to calculated reliable indicator of each componentrespectively. It regarded the main arch, arch columns and bridge decks three parts as series system to determine reliable indicator of the whole structure. It also analyzes thereliability of each random variable’s sensitivity of the bridge and structural responsefunction of distribution.3, In order to verify the reasonableness of reliable indicator division, select JCmethod to calculate a reliable indicator of bridge superstructure, which is currently moremature. The calculated results compared with the results of the assessment inaccordance with criterion, which verified the bridge category based on reliableindicators are correct. The calculated results of hybrid algorithm compare with theresults use JC method, so verified hybrid algorithm to calculate structural reliabilityindex is correct.This paper divided the security level of bridges by using reliable indicator,itovercome the shortcomings in subjectivity of traditional bridge security level divisionand assess two existing reinforced concrete bridges according to this theory andapplicability of this method is verified.