A Study Of Assessment Theory And Its Application For Existing Bridges

More and more structural damages can be detected in existing bridges for several reasons including increasing vehicle loads as a result of national economic development, problems in design and construction, and structural aging, etc. The safety and serviceability of existing bridges are weakened seriously as a decrease of structural capacity caused by these damages. So the evaluation and reinforcement for existing bridges is increasingly necessary.In this article, various mathematical theories in bridge assessment are discussed among Markovian model, Penn, model, mean soundness model, National Bridge Inventory (NBI) based model, Thoft-Christensen model, semi-Markovian model, BRIDGIT model, PONTIS model, and partial linear flat-S model.Base on these assessment theories, practical methods of bridge evaluations are presented in detail, including methods based on appearance observation, design codes, load testing, expert experience, layer analysis, fuzzy mathematics, theory of reliability. The comparison and contrast are made based on the presentation of different methods above, and their serviceability and applications are also introduced in this article. Condition states are described and compared between Chinese and international existing bridgesA real project is taken as an example in this article so as to evaluate the reliability of this bridge. The level of which is determined according to its evaluation results. In addition, the suggestion of reinforcement is provided for both this bridge and similar type of bridges.Finally, the characteristics and limitations for both traditional and new methods of bridge assessment are present, and the possible trend for future bridge assessment is discussed.