Studying On Reliability Theory Used For The Assessment And Strengthening Of Simple Supported Beam Existing Bridge

Bridges are the hinges of traffic system ,playing an important role in the national economic and society. Along with the extension of the bridge service life, international community increasingly pay attention to the safety of the existing bridge . Now the assessment of bridges is becoming the realm which need to enhance urgently ,so the reasonable evaluation on the safety of bridges, is an urgent and important task.The reliability assessment of existing bridges structure specially the system of existing simple supported beam RC bridge based on reliability theory ,at the same time , using the assessment conclusion availably on the time of deciding the strategy of bridge reinforcement is an urgent task in engineer field . To the problem , the dissertation do the work on the reliability theory used in the assessment and reinforcement of simple supported beam RC bridge and provides an practicable means to resolve the question based on reliability theory .The main achievement of this dissertation are briefly mentioned as follows :1 In the first ,the dissertation probes into the connotation and developing direction about the bridge assessment , appraise their advantages and disadvantages on all kind of means of bridge assessment , draw a conclusion that it is an urgent task to use reliability theory in the assessment and reinforcement of simple supported beam RC bridges 2 Provide the systemic probability models on their resistance .function effect and related statistical index of simple supported beam RC bridges, which establish theoretic and practical foundation for calculating the reliability of simple supported beam RC bridges.3 Combinated with actual circumstance for beam bridge.establish relative but uniform function and ultimate equation for a certain and disabled model Create a condition for calculating reliability.4 Based on the foretime productions , studying the reliability calculation for the system of existing simple supported beam RC bridge,and using the way of reliabilitycalculation which is prescribed by criterion to caculation a practical bridge. For complicated system relatively , point out the further thoughtway to calculate reliability.5 Based on the systemic discussion and summing-up practicability deeply ,summing-up the currently strengthening means of bridges in engineering practicability ,and discuss to caculate correlative resistance of bridge structure which need to be strengthened on the premise of prescribing the aim reliability index, conbinated with the reliability model and statistical parameters of existing simple supported beam RC bridge , accordingly ,to design for the strengthening of bridges .6 In the paper ,summing-up detailed course for calculating reliability of existing simple supported beam RC bridge structure ,at the same time , pointing out the course and idea as a whole for using the reliability index to calculate structure resistance while strengthening existing simple supported beam t RC bridge.The assessment of bridges is a studying field which is more synthess subject and correlate with many complicated theory, the researches are extremely difficult ,but those applied prospect in enginerring are vast ,the theoretical worth is significant .There is a series of achievement in this dissertation ,much research work is taken for the first time.Along with thorough research and an urgent need for engineering application,this studying field will be developed indepth .