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.

考虑到基础设施中公路桥梁的根本性，至关重要的是在其生命周期内监控其健康状况。为了实现这一目标，本文提出了一种基于车辆的长距离光纤布拉格光栅（FBG）应变传感器测得的应变响应的分形维数，用于在行驶中的车辆下的公路桥梁的仅输出损伤检测方法。在这种方法中，通过在完整和损坏状态下归一化分形维数曲线的变化来检测桥梁损坏。初步通过数值案例验证了该方法的有效性，并具有抗噪能力。然后，建立了1:10比例的桥梁车辆模型系统。一系列实验案例研究结果表明，该方法可以有效地检测桥梁损伤，并且不受车辆参数的影响。