Research On Durability Experiment And Reliability Evaluation Of Existing Reinforced Concrete Bridge Member

Recently, With the increase of dangerous and old bridge in our country, there is a serious problem which many bridge researchers face with: how to estimate technology state of existing bridge structure and make reliability evaluation methods by scientific detective and test ways to provide scientific basis for rehabilitation of dangerous and old bridge.To give a technological support for good maintenance, strengthening and removal of old bridge, especially the old bridge in short of data, it is very important to make a technology data bank of the same period, the same zone and the same type bridge structure through systematic test study. In this thesis,firstly,the problems and the detective method of existing reinforced concrete bridge are summarized in detail, according to international research and our experience. A method how to choose the detective location and inspect the state of rebars of old bridge in short of data is proposed. Secondly, a destructive test of two ribs is carried out, which are removed from the north gate of Chang-ning bridge in Hunan province:the defecive state, concrete crack and rebar corrosive level are tesed by combined method composed of observation, local failure and nondestructive testing; the common damages and the causes of damages of existing bridge are analysed; influence factors of the durability are discussed; it is verified that the degradation of durability makes a notable impact on bearing capability; the concept of the weakest section of durability is presented. Lastly, the weakest section of durability is given by analytic hierarchy process.Further more ,the reliability of the existing reinforced concrete member is estimated by neuro-fuzzy network.In this paper , the next durability research is provided with experimental data and the mothed for reliability evaluation is discussed theoretically.