Strengthening And Redevelopment Of Exiting Reinforced Concrete Simply Supported Girder Bridge

Reinforced concrete simple supported beam bridges has been widely used in the middle and small span bridges, because of their advantages such as structural lightweight, simple, explicit force, low cost, easy construction. Recently, a large number of reinforced concrete simple supported beam bridges have been constructed. Owing to the neglect of durability about early bridges, after more than ten years of service, a variety of injuries of the structure occurred because of material aging and overloading. These diseases and defects of bridges would lead to serious hidden danger for the future transportation, and how to take care of the aged bridges and how to use the aged bridges is very important in transportation field. So these bridges are requiring detection, assessment, strengthening and reconstruction.Before the maintenance and strengthening, the proper detection and assessment of the bridges should be done so as to assess the actual condition and loading capacity, to analyze the causes of the diseases and defects, and then to propose effective measures for the maintenance and strengthening.On the basis of the research results about the bridge assessment and strengthening at home and abroad firstly, this thesis takes the Qinglong grade separation bridge and Zhennan Ⅱ bridge in Sichuan Dajian highway(S103) as engineering background, to further discuss the detection, the strengthening method, the load test of the existing reinforced concrete supported girder bridges. The main contents are as follows.1、We summarize all the diseases and defects of reinforced concrete simple supported beam bridges, analyze the reason of these diseases and defects. Then we have a better understanding of these diseases and defects about the reinforced concrete supported girder bridges.2、Before strengthening, we perform the detection of the reinforced concrete supported girder bridges, and assess the bridges according to the detection results and structural assessment method.3、According to the detection and test results, the existing diseases of the bridge are analysed and proper strengthening method is proposed.4、After strengthening, we perform the load test, assess the performance state according to the check index of stress and displacement under occupancy load.5、Compare the performance state before and after strengthening the existing reinforced concrete arch bridge according to the static and dynamic load test result.