基于长标距光纤应变传感器的桥梁挠度识别技术研究

Research on bridge deflection identification technology based on long gauge fiber optic strain sensor

主梁挠度能够直观的反映桥梁的工作状态及适用性,通过监测变形可以实时了解桥梁运行状态及损伤情况,是评估桥梁健康状态的重要指标。开展了基于长标距光纤应变传感器的桥梁挠度识别技术研究,首先介绍了基于长标距应变的挠度计算方法及原理,通过室内简支钢梁静力试验验证了该方法的有效性与可靠性。然后将该方法推广应用于实桥上,采用长标距应变传感器对桥梁的动态应变响应进行实时监测,基于共轭梁算法实现结构动挠度反演,与封闭式连通管法监测的动挠度进行对比,结果表明该方法具有足够的精度,满足挠度测量需求,能够同时实现结构应变、主梁挠度两种结构安全关键参数的识别,一专多能,可在实际工程中进行推广应用,具有较高的应用价值。

The deflection of the main beam can intuitively reflect the working status and applicability of the bridge, and the operating status and damage of the bridge can be understood in real time by monitoring the deformation, which is an important indicator for evaluating the health status of the bridge. In this paper, the research on deflection identification of bridges based on long gauge fiber optic strain sensor is carried out. Firstly, the deflection calculation method and principle based on long gauge length strain are introduced. The validity and reliability of the method are verified by indoor static tests of simply supported steel beam. Then this method is extended to real bridges. The long gauge optical fiber sensor is used to monitor the dynamic strain of the bridge in real time. The dynamic deflection of the structure is realized based on the conjugate beam algorithm. Comparison with the dynamic deflection monitored by the closed connected pipe method, the results show that that the method has sufficient accuracy to meet the deflection measurement requirements. It can realize the identification of two key structural safety parameters of strain and deflection at the same time. It can be applied in practical engineering and has high application value.