基于光纤光栅的斜拉索振动参数监测实验研究

斜拉索是斜拉桥的主要受力构件 ,对其动力特性进行监测具有重要意义。斜拉索工作条件恶劣 ,现有的测试方法难以实现长期在线监测 ,实现斜拉索的振动在线测量 ,传感器是问题的关键。光纤光栅传感器具有极其优良的稳定性 ,已被证实适用于长期监测 ,在结构监测领域具有非常广泛的应用前景。笔者提出了一种基于光纤光栅传感器的斜拉索动力特性在线监测方法 ,建立了用光纤布拉格光栅作传感器监测斜拉索振动的测量模型 ,为验证该模型建立了模拟试验装置 ,在实验室进行了模拟实验研究 ,并将光纤光栅和传统的电阻应变片两种测量方法进行了实验对比。与传统测试手段相比 ,该方法结构简单 ,成本低 ,并能实现斜拉索动力特性的长期在线监测。

On-line Monitoring Method for Stayed-cables Dynamic Response Based on Fiber Bragg Grating

Stayed-cables are the main load-bearing components of cable-stayed bridges. Therefore, the dynamic response monitoring of stayed-cables is very important and necessary. Because of the rough-weather works, the conventional sensors couldn't meet the requirement of on-line monitoring of stayed-cables of cable-stayed bridge. Fiber-optical Bragg grating strain sensors hold a great deal of potential for structural monitoring because of their exceptional stability and demonstrated potential for long-term monitoring. Directed toward the feature of the stayed-cables, a new dynamic response monitoring method for the stayed-cables of cable-stayed bridges is introduced. The monitoring theory for dynamic response of stayed-cables utilizing fiber Bragg grating as sensors is proposed, and the model for monitoring is derived. The stimulated experiment setup is installed to validate the monitoring method proposed; and simulation experiment is done. Two strain measurement methods of fiber grating and resistance strain chip are experimentally contrasted. Both the theoretical and experimental results show that the method presented could be used in on-line monitoring of the dynamic responses of the stayed-cables of cable-stayed bridges, and the monitoring system is simple in structure and reasonable in cost.