Experimental Investigation Of Rapid Damage Detection Based On Bridge Quasi-static Influence Surface

The most direct and effective method to evaluate construction quality and carrying capacity of the bridge is load test. However, conducting load test needs much time, and the bridge needs to be closed during the test. Therefore, load test is not economical for damage detection of small and medium sized bridge. It is of great significance to put forward a practical rapid damage detection method with little or no interruption for small and medium span bridges.The research status of bridge structure damage detection is introduced in this paper, and the defects of the current damage detection method for small and medium span bridges are analyzed. Based on the existing research results, this study puts forward the general idea of rapid damage detection for small and medium span bridges according to bridge status classification.For the second class bridges, the damage detection method based on displacement influence surface is proposed. Using displacement data measured by the sensor, the influence line or the influence surface of the structural displacement can be established, and the Hankel matrix is constructed to extract the damage index. After repeating the test, comparing data of the reference state with data of the damaged state, hypothesis testing method was adopted to detect the damage.A quasi-static load test was conducted on a simply supported bridge model. Measured data were used to verify the effectiveness of the algorithm proposed in this paper. The effectiveness of the two methods were compared in different damage cases, and suggestions were given.According to the algorithm, Visual Basic language was used to develop a rapid damage detection software, and load test data were used to establish the reference state database. The software has the advantages of speed, accuracy, stability and aesthetics, which is the basis for the application of this method in practical engineering.