For long-span cable-stayed bridges, cables are one of the most important components to resist various actions. With the application of structural health monitoring technique, real-time recording of cable forces is achieved, and hence, the warning system on cable anomaly established. However, it is still difficult and there are challenges to conduct the warning system effectively, especially due to the phenomena of false alarm or omission. A practical reason is the warning index’s sensitivity to the ambient environment. Temperature variations, for instance, usually disturb the force-based cable anomaly warning and result in the false evaluation of structural condition. In view of eliminating the effects of environmental temperature, cointegration, a statistical concept from econometrics, is employed in cable anomaly warning studies. An approach that extracts warning index by linear combination of two non-stationary time series using the cointegration algorithm is developed in order to produce a more stationary cointegrated residual series (warning index series). The calculated stationary relationship between two time series is insensitive to the influence of environmental temperature and is capable of cable anomaly warning. Specifically, the framework of the cable anomaly warning system is first proposed. Subsequently, time-series test methods are introduced to check the non-stationary order and calculate the cointegration parameters of measured cable forces and environmental temperature. The computed cointegrated residual series is fed into statistical analysis as a warning index and the procedure of cable anomaly warning under the influence of environmental temperature is illustrated in detail. Finally, a case study for a cable-stayed bridge is demonstrated with results and discussions.

中文翻译：

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基于结构健康监测数据的拉索异常预警协整方法——在斜拉桥中的应用

对于大跨度斜拉桥，索是抵抗各种作用的最重要的构件之一。应用结构健康监测技术，实现了索力的实时记录，从而建立了索异常预警系统。然而，有效地进行预警系统仍然存在困难和挑战，特别是由于存在误报或遗漏现象。一个实际原因是警告指数对周围环境的敏感性。例如，温度变化通常会干扰基于力的电缆异常警告，并导致对结构条件的错误评估。为了消除环境温度的影响，在电缆异常警告研究中采用了计量经济学中的统计概念协整。开发了一种使用协整算法通过两个非平稳时间序列的线性组合来提取警告指数的方法，以产生更平稳的协整残差序列（警告指数系列）。计算出的两个时间序列之间的平稳关系对环境温度的影响不敏感，能够进行电缆异常预警。具体来说，首先提出了电缆异常预警系统的框架。随后，引入时间序列测试方法来检查非平稳阶并计算实测索力和环境温度的协整参数。计算出的协整残差序列作为预警指标输入统计分析，详细说明了环境温度影响下电缆异常预警的过程。最后，通过结果和讨论展示了斜拉桥的案例研究。