In this paper, an innovative two-level damage detection method applicable to real-world online structural health monitoring (SHM) systems is proposed for in-service large steel arch bridges. The method consists of Level 1 damage detection practice that includes strain data acquisition and damage location using the damage index based on the fractal theory, and Level 2 damage detection practice that includes acceleration sample acquisitions and dynamic model updating to quantify the damage. A numerical case study of the Yingzhou bridge based on various damage cases demonstrated the effectiveness of the proposed damage detection method. It is revealed that Level 1 damage detection is sufficiently robust against the standard measurement noise and normal temperature variations. The study results also indicated that the accuracy of Level 2 damage detection largely depends on whether the initial structure imperfections are taken into account, and whether the utilized model updating method is effective under model errors.

中文翻译：

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基于分形理论和模型更新技术的异形钢拱桥损伤检测新方法

在本文中，针对在役大型钢拱桥提出了一种适用于现实世界在线结构健康监测（SHM）系统的创新两级损伤检测方法。该方法包括一级损伤检测实践，包括使用基于分形理论的损伤指数获取应变数据和损伤定位，以及包括加速度样本采集和动态模型更新以量化损伤的二级损伤检测实践。基于各种损伤案例的瀛洲桥数值案例研究证明了所提出的损伤检测方法的有效性。结果表明，1 级损伤检测对于标准测量噪声和正常温度变化具有足够的鲁棒性。