Abstract Our nation’s infrastructure is aging and deteriorating which increases the need for condition assessment and structural health monitoring. For this purpose, there is a growing interest in using non-contact monitoring methods because of the challenges associated with deploying and installing conventional instrumentation. Target-tracking digital image correlation (DIC) is among these methods and is the focus of this paper. Several research activities have been conducted at the University of Nevada, Reno in the field of dynamic monitoring using DIC and presented here. The first part of the paper is concerned with a large-scale laboratory application where target-tracking DIC was utilized to monitor the response of a bridge structure tested under bidirectional earthquake shaking. The 3D dynamic response of the bridge, along with modal properties, i.e. natural frequency, damping ratio, and mode shapes, were measured or determined using both DIC and conventional instrumentation then compared for validation purposes. The second part of the paper presents results from field monitoring of an actual footbridge under pedestrian loading to determine the vibration frequencies of the bridge, and again compare it against results from conventional accelerometers for validation. From both applications, the DIC is demonstrated to successfully capture (1) peak and residual bridge deck rotation and deformation under different earthquake intensity levels and (2) modal properties for system identification. Practical DIC sampling rates were used to accurately monitor and capture the dynamic response of bridges, which shows a high potential for using DIC for larger structural health monitoring applications and future reconnaissance works.

中文翻译：

---

基于目标跟踪数字图像相关的桥梁结构健康监测和地震反应评估

摘要 我们国家的基础设施正在老化和恶化，这增加了对状态评估和结构健康监测的需求。为此，由于与部署和安装传统仪器相关的挑战，人们对使用非接触式监测方法越来越感兴趣。目标跟踪数字图像相关（DIC）是这些方法之一，也是本文的重点。内华达大学里诺分校已在使用 DIC 进行动态监测领域开展了多项研究活动，并在此介绍。本文的第一部分涉及大规模实验室应用，其中目标跟踪 DIC 用于监测在双向地震震动下测试的桥梁结构的响应。桥梁的3D动态响应，使用 DIC 和传统仪器测量或确定模态特性，即固有频率、阻尼比和模态形状，然后进行比较以进行验证。论文的第二部分介绍了在行人负载下对实际行人天桥进行现场监测的结果，以确定桥梁的振动频率，并再次将其与传统加速度计的结果进行比较以进行验证。从这两个应用中，DIC 被证明可以成功捕获 (1) 在不同地震强度水平下的峰值和剩余桥面板旋转和变形，以及 (2) 系统识别的模态特性。实用的 DIC 采样率用于准确监测和捕获桥梁的动态响应，