Study On Method Of Technical Condition Assessment For Strengthened Concrete Girder Bridges

Since the founding of the new China, the transportation industry used to have a rapidly development, and considerable progress had also been achieved in the construction of bridges and highways at the meantime. However, due to various reasons, an increasing number of bridges began to expose some of the issues, and public attention was drew largely to affairs such as the inspection, evaluation, maintenance, repair and reinforcement of the bridge. Bridge reinforcing is a good way to restore the safety, durability and applicability of the bridge, since it is sustainable, environment friendly, and of economic efficiency. But there is no corresponding standardized assessment method directly available for the technical condition of bridges that have been reinforced, which brought some difficulties for their inspection and assessment.The study on method of technical condition assessment of strengthened concrete girder bridges, called strengthend girder bridges for short, which is one of the most popular highway bridge type, is of great significance. It can be a representive research object of the technical condition assessment method for strengthened bridge. In this paper, the strengthened concrete girder bridge was distinguished from regular bridges from perspective of structural members. On the evaluation methods of strengthened structural members, several works have been done as follows:① Do a comprehensive study on the typical strengthening method, as to be the reference and basis of the evaluation index of strengthend girder bridges.② In view of the shortage of the general AHP method, the fuzzy comprehensive evaluation method based on the improved AHP is established, which makes the weight more objective and reasonable.③ Aiming at different strengthening methods and strengthening purposes, the technical state evaluation index system of concrete bridge after reinforcement is established.④ From the strengthening design principle and strengthening, according to the lifting of the bearing capacity, combined with the experience of the experts, the weight of the reinforcement structure is established.⑤ According to the comprehensive evaluation of the general, mostly depending on the relative importance of each element weighted in the evaluation process, the weight of each element remains constant is proposed in this paper uses variable weight principle of each element of the evaluation method of weighted state, makes the evaluation results more balanced;Based on the existing norms and common evaluation methods, as well as improved AHP and fuzzy comprehensive evaluation method, the author established a set of evaluation methods directed at strengthened bridges, which includes the classification and determination of indicators in reinforcement structure as well as the determining method of weight of reinforce structure in structural members after strengthening. The difference between standardized methods and this proposed method was analyzed comparatively, through citing the Interchange Overpass of Wuhuangtongchengpu as an example. Moreover, the rationality of this proposed method was also evaluated by the load test results. And it also shows that the evaluation method of this paper has the characteristics of comprehensive and balance. It can also reflect the state of the strengthened structure or each component more actually.