Research On The Effects Of The Durability Of Reinforcement Corrosion On Bridge Structures

Reinforced concrete bridge structure combines of steel and concrete,which has strong tensile strength and the other has strong compressive property.Because of this characteristic,it has been wide use in the global domestic field.However,the northwest is the place where the climate is relatively dry.The reinforced concrete bridge structure is corroded by the environment during the operation service.The change of the environment temperature and humidity and the content of carbon dioxide,oxygen and water in the air have a significant effect on its durability.Resulting in corrosion within the structure of steel is concrete protection layer rust cracking or peeling off and bridge mechanical properties.When the bearing capacity of the bridge began to decrease,its reliability also will be reduced,the maintenance and reinforcement will be needed.Taking into account the current large number funds of countries to strengthen the strengthening,China's large-scale construction,the limited funds of future maintenance,we can reveal the potential danger of existing bridges through the study of new and existing bridge time-varying reliability.Departments can take timely measures to exclude or deal with the uncertain factors which is harm the health of the bridge,and then make a maintenance,reinforcement or demolition of the decision to repair the durability life of the bridge structure.This has significant economic and social significance.Based on the research and research results of durability research both at home and abroad,this paper has investigated the causes of corrosion resistance of bridge reinforced concrete bridge and analyzed the influence mechanism of bridge steel structure on the durability of bridge structure in Jiayuguan of Northwest.Based on the analysis of the causes of durability,three kinds of durability state and their life end of the bridge structure durability have been established based on the dynamic reliability theory,and quantified the lower limit of the durability limit state.The dynamic reliability theory has been used to analyze the influencing factors on the dynamic reliability of the bridge durability life.Considering the change of the environment,the residual life of the bridge structure in the northwest which is based on the time-dependent reliability has been calculation.Based on the technical background of Lianhuo expressway and the new 20 m prestressed reinforced concrete box girder bridge in Jiayuguan,this paper has analyzed the durability life of the bridge structure in its service period in the northwest.And has taked into account the changes in the reliability of the environment and its significance.Taking the Middle Bridge 005 in Jiayuguan on G30 expressway as an engineering example,combining with its site investigation and considering the time changes of concrete strength,the effective cross section loss and the strength of steel bars,the bridge durability of bearing capacity life has been predicted based on the time-varying reliability,and has put forward the theoretical basis for reasonable reinforcement measures.