Study On Bridge Condition Synthesis Assessment And Forcasting

The bridges will gradually wear down under the circumstances of the natural environment, such as the atmosphere erosion, the changes of the temperature and the humidity, and applied environment, such as the loading, the fatigue of the material and the structure. This is an irreversible process. Recently, bridge deterioration with time and ever increasing traffic loads raise concerns about safety and durability of aging bridges. The management and optimum repair strategy of bridges have earned world-wide attention. In order to keep pace with the growing demand for deteriorating bridges with financial resources, decision makers have to evaluate the safety and durability of the aging bridges correctly. It is based on this, optimum repair strategy can be made. Against the puzzles in safety and durability evaluation and repair decision of existing bridges, this paper performed the following studies:Chapter 1 expatiates the purpose of this dissertation, and introduces the content and researching actuality of bridge condition evaluation and forecasting;Chapter 2 summarizes the content and common characteristic of current bridge condition evaluation methods firstly. Then according to AHP bridge condition synthesis evaluation model is established, and a simply supported RC bridge is taken for an example to present relatively reasonable index system. A method is put forward here——variable weighted sorting method to calculate index weight. Consulting criterion and experts'experience the grade standards of indexes are listed, and applying grey correlation analysis method to calculate value of the indexes, of which the form is a serial data. The last, an actual bridge uses synthesis evaluation model, of which calculating result is the same as conclusion of the experts. So the bridge condition synthesis evaluation model of this dissertation is relatively in reason;Chapter 3 discusses defects of current bridge condition evaluation methods, and analyzes various factors, which bring bridge degeneration. Consulting criterion of some countries and experts'experience the grade standards of factors are listed. Then Fuzzy Theory is used to find out the relation between bridge average degenerating ratio and various factors. Bridge average degenerating ratio is computed by Fuzzy Synthesis Evaluation. Finally, a sample proves the feasibility of the method;Chapter 4 first indicates the grey characteristic, which is information inadequacy...