Department of Engineering Mechanics, Hohai University, Nanjing 210098, China.
Jiangxi Provincial Key Laboratory of Environmental Geotechnical Engineering and Disaster Control, Jiangxi University of Science and Technology, Ganzhou 341000, China.
Sensors (Basel). 2019 Oct 2;19(19):4272. doi: 10.3390/s19194272.
Curved continuous girder bridges (CCGBs) have been widely adopted in the civil engineering field in recent decades for complex interchanges and city viaducts. Unfortunately, compared to straight bridges, this type of bridge with horizontal curvature is relatively vulnerable to earthquakes characterized by large energy and short duration. Seismic damage can degrade the performance of CCGBs, threatening their normal operation and even resulting in collapse. Detection of seismic damage in CCGBs is thus significantly important but is still not well resolved. To this end, a new method based on wavelet packet singular entropy (WPSE) is proposed to identify seismic damage by analyzing the dynamic responses of CCGBs to seismic excitation. This WPSE-based approach features characterizing damage using synergistic advantage of the wavelet packet transform, singular value decomposition, and information entropy. To testify the algorithm, a finite element model of a typical CCGB with two types of seismic damage is built, in which the seismic damage is individually modeled by stiffness reductions at the bottom of piers and at pier-girder connections. The displacement responses of the model to El Centro seismic excitation is used to identify the damage. The results show that damage indices in the WPSE-based approach can correctly locate the seismic damage in CCGBs. Furthermore, the WPSE-based method is competent to identify damage with higher accuracy in comparison with the wavelet packet energy based method, and has a strong immunity to noise revealed by robustness analysis. An array of responses used in this approach paves the way of developing practical technologies for detecting seismic damage using advanced distributed sensing techniques, typically the optical sensors.
曲线连续梁桥（CCGBs）在近几十年的土木工程领域中得到了广泛应用，用于复杂的互通式立交和城市高架桥。然而，与直线桥相比，这种具有水平曲率的桥梁在地震作用下相对脆弱，地震具有能量大、持续时间短的特点。地震损伤会降低 CCGB 的性能，威胁其正常运行，甚至导致倒塌。因此，检测 CCGB 的地震损伤具有重要意义，但仍未得到很好的解决。为此，提出了一种基于小波包奇异熵（WPSE）的新方法，通过分析 CCGB 对地震激励的动力响应来识别地震损伤。这种基于 WPSE 的方法利用小波包变换、奇异值分解和信息熵的协同优势来表征损伤。为了验证算法，建立了一个具有两种类型地震损伤的典型 CCGB 的有限元模型，其中分别通过降低桥墩底部和墩梁连接处的刚度来模拟地震损伤。使用模型对 El Centro 地震激励的位移响应来识别损伤。结果表明，基于 WPSE 的损伤指标可以正确定位 CCGB 中的地震损伤。此外，与基于小波包能量的方法相比，基于 WPSE 的方法能够更准确地识别损伤，并且通过稳健性分析显示出对噪声具有很强的免疫力。该方法中使用的一系列响应为使用先进的分布式传感技术（通常是光学传感器）检测地震损伤开发实用技术铺平了道路。
