土木结构的光纤光栅与布里渊共线测试技术

Measurement technique based on the FBG-BOTDA(R) for Infrastructures

针对目前分布式应变测试技术存在精度和空间分辨率均较低、采样频率低、系统造价高等缺点,以及高精度的单点应变测试技术无法解决范围广、距离长、变形大、位置隐蔽等特征的结构损伤监测问题,考虑实际工程传感器布设占据结构健康监测系统造价的极大比例,提出将光纤布里渊全尺度传感技术和准分布式高精度光纤布拉格光栅测试技术相结合构建融合全尺度分布式和局部高精度共线的智能监测方法与集成系统,并研制开发出支持该技术方便实施的高强、高耐久性传感探头,即无焊点超长尾纤光纤光栅—纤维增强聚合物复合智能筋,通过三点弯曲钢筋混凝土梁应变分布试验和实体平行钢丝拉索索力测试试验,验证了该系统的有效性和突出优点。该技术有望为实际大规模、大跨度复杂结构提供理想的损伤监测手段。

There are disadvantages of current distributed strain monitoring technology, such as low accuracy and spatial resolution, low sampling frequency, and large cost. Single-point strain measurement technique with high-precision cannot cover the damage features of structures of large span, long distance, large deformation and hidden location, and the cost of installation of the sensors takes up a big proportion of structural health monitoring system. An integrated system of distributed full-scale and local monitoring technique with single optical fiber is developed by combing the Brillouin distributed sensing technology with local high-precision optical fiber Bragg grating （FBG） technology. A highstrength and durable strain cell based on this concept, without weakness, is also produced, named as Fiber Bragg Grating-fiber-reinforced polymer （FRP-OFBG）. Experiments of a reinforced concrete beam under three-point bending and a full scale cable are carried out to verify the effectiveness and the advantages of the integrated system. The result indicates the integrated system can be used for monitoring of large-scale, complex and long-span structures.