A rapid output-only damage detection method for highway bridges under a moving vehicle using long-gauge strain sensing and the fractal dimension

摘要

Considering the fundamentality of highway bridges in infrastructure, it is essential to monitor their health state during their lifetime. To achieve this goal, this paper presents an output-only damage detection method for highway bridges under a moving vehicle, which is based on the fractal dimension of strain responses measured by long-gauge fibre Bragg grating (FBG) strain sensors. In this method, bridge damage is detected through changes in the normalized fractal dimension curve under intact and damaged states. The method is initially verified to be effective through a numerical case study, and has anti-noise capability. Then, a 1:10 scale bridge-vehicle model system is established. A series of experimental case studies results show that this method can detect bridge damage effectively, and is not affected by vehicle parameters. The method can be used not only for rapid damage detection but also for long-term bridge monitoring without interrupting traffic. (C) 2020 Elsevier Ltd. All rights reserved.