Durability Evaluation And Stability Analysis On In-service Concrete Bridge Of Qilin Expressway

As the throat of road and the lifeblood of transport system,bridge plays the role of turning the chasm into a thoroughfare.With the extension of service life,the bridge structure will experience different degrees of deterioration and damage.The accumulation of damage will result in the decrease of the durability of the bridge structure and the weakening of the seismic capacity.In order to ensure the normal operation of the bridge in service,it is necessary to carry out durability assessment and analysis of post-deterioration seismic capacity.This paper starts from the Shanxi Provincial Department of Communications Science and Technology Project(SJ-2016-16),with the in-service bridge in the Qixian-Linfen section of Shanxi Province Qilin Expressway as the object of study.It mainly studied the following aspects:(1)This paper investigated and analyzed the disease and damage of the bridge in the Qilin Expressway of Shanxi Province,and also tested the durability of the bridge in-service.The durability test on the twenty-five typical bridges of this line,was related to the strength of concrete,the thickness of reinforced protective layer,the carbonization of concrete,the corrosion of steel bars,the width and depth of cracks and the content of chloride ions,which provided basic data support for the durability assessment and the post-capacity analysis.(2)A durability evaluation model was established by using the analytic hierarchy process method for the bridge of Qilin Expressway in Shanxi Province.The durabilityevaluation index was obtained according to the results of the typical disease analysis.The current standard and the test result were combined and the standard evaluation function was constructed by the dimensionless model,which makes the index evaluation score quantified.Besides,the variable weight theory was introduced into the calculation of the evaluation index weight to obtain the reasonable,scientific and applicable durability evaluation system.(3)On the basis of durability test,the seismic capacity analysis after durability damage was carried out.Starting from the study of seismic analysis parameters,the analysis includes geometric damage of cross section,deterioration of steel bar performance and deterioration of concrete performance.The seismic capacity of Mamu Fenhe bridge was analyzed with the help of UCFyber software.This study also predicted the weakening durability damage and seismic capacity of 30 years,50 years,70 years and 100 years,which shows that the weakening of curvature ductility is obvious during the 30~50 years of service.The result can be applied to seismic response analysis on the durability damage of bridge structure of Qilin Expressway in Shanxi province.In this paper,the practical application and feasibility of the method are verified by the practical evaluation of the durability evaluation system and the post-deterioration seismic capacity analysis method of Ma Mu Fenhe Bridge in Shanxi Province.The results show that the method is practical and feasible.This study provides some guiding significance for the maintenance,repair and reinforcement of bridge structure in Qilin expressway,and also technical reference for other highways in Shanxi Province.