| Summary: | 碩士 === 朝陽科技大學 === 營建工程系碩士班 === 102 === In recent years, the damage detection and evaluation of aging infrastructures becomes an important topic for domestic and international engineering research due to the increasingly high cost of constructing new structures. In present study, we would like to explore the idea of using the dynamic displacement response of a bridge corresponding to a heavy truck passing a defective or a non-defective bridge to evaluate the stiffness distribution along the bridge and assess the damage of the bridge. The study is divided into two parts- numerical simulation and experiment.
Analysis method is as following: Measure the dynamic displacement at one position. Transfer time into position of the moving vehicle to obtain a dynamic displacement influence line. And then use Windows filtering to obtain quasi-static influence line. The curvature is as quadratic differential of the influence line. Finally the bridge stiffness can be obtained by dividing the moment diagram for point load applied to the displacement measurement position to the distributed curvature.
In the numerical study, the continuous solution program (1DC.FOR) which perform the dynamic analysis in the frequency-domain is used , for parametric study. The parameters include the position, range and stiffness loss of the defects. The defect stiffness and position can be back cacluated from the percentage of stiffness loss, and the width of the stiffness decreasing zone.
In the experiment, the bridge girder was simulated by the H-beam and the moving truck was simulated by the rolling of the steel ball. Preliminary results indicate that the stiffness near the damage zone decreased substantially.
|
|---|
