Abstract

This article uses extracted bridge mode shapes to detect bridge damage, including both local damage such as that due to a bridge strike and global damage such as that due to foundation scour. Typically, only one accelerometer is required, which is mounted on an instrumented vehicle passing over the test bridge. This concept is referred to as ‘drive-by’ bridge health monitoring. For a simple vehicle/bridge interaction (VBI) model, where the vehicle is represented as a moving sprung mass, a closed-form solution for the bridge mode shape is derived from the acceleration response of the instrumented vehicle. The validity of the proposed algorithm is numerically verified using a VBI model. In addition, it is shown that the extracted mode shape can be used to assess the bridge condition. A damage index based on the extracted mode shape is proposed to detect bridge damage and to provide an indication of the damage level. In the numerical study, the factors that affect the accuracy of the proposed algorithm are investigated, including the vehicle speed and measurement noise. Two laboratory experiments are conducted to validate the mode shape extraction and bridge damage detection processes for cases of both local and global damage.

摘要

本文使用提取的桥梁振型来检测桥梁损坏，包括由于桥梁撞击造成的局部损坏和由于地基冲刷造成的全局损坏。通常，只需要一个加速度计，它安装在经过测试桥的仪表车辆上。这个概念被称为“免下车”桥梁健康监测。对于简单的车辆/桥梁相互作用 (VBI) 模型，其中车辆表示为移动的簧载质量，桥梁模式形状的封闭形式解决方案来自仪表车辆的加速度响应。所提出算法的有效性使用VBI 模型进行了数值验证。此外，还表明提取的模态振型可用于评估桥梁状况。提出了基于提取的模态形状的损坏指数来检测桥梁损坏并提供损坏程度的指示。在数值研究中，研究了影响算法精度的因素，包括车速和测量噪声。进行了两个实验室实验以验证模式形状提取和桥梁损坏检测过程对于局部和全局损坏的情况。