基于光纤传感技术的体外预应力结构全寿命监测与安全评估

With the development of unbonded steel strand and reinforcement project, research and application of external prestressed structure have gradually become one of the hot spots in the field of civil engineering. As the key components in external prestressed structures, the stress state and the actual stress of prestressed tendons play a key role for the normal service function and safety of structures. Unfortunately，nowadays，there are no qualified techniques to treat with this issue due to the fact that monitoring sensors may not survive the harsh construction environments and the time-dependent service life of the large-span prestressed structures．In this study, to meet the needs of prestress monitoring for practical external prestressed engineering, a novel unbonded smart steel strand was developed combining with optical fiber sensing technology and common steel strands in the external prestressed structure. It is structural materials and functional materials in one and has both mechanical and sensing properties The corresponding method and technology of prestress monitoring for external prestressed structure was offered, and life-cycle prestressing evolution rules and safety assessment method were studied. Finally, the above technology are applied in practical engineering to establish a demonstration system..Through the research, the method and technology of life-cycle monitoring for external prestressed structures will be developed, the prestressing evolution rules will be revealed and a convenient safety assessment method will be proposed.

随着无粘结钢绞线和加固工程两项技术的发展，体外预应力结构的研究和应用已经逐渐成为土木工程界的热点问题。预应力筋作为体外预应力结构中的关键受力部件，其受力性态和实际预应力的大小对体外预应力结构的正常服役功能和安全性起到关键作用。针对现阶段满足实际工程需要的预应力监测手段匮乏这一土木工程界难题，将光纤传感技术与体外预应力结构常用钢绞线相结合研制兼具受力与传感特性、集结构材料和功能材料于一体的无粘结智能传感探头。发展相应的体外预应力结构预应力监测方法和技术，探讨体外预应力结构全寿命预应力演化规律及其安全评定方法。最后，将上述技术应用于已经明确的实际工程，建立示范系统。. 通过上述研究，发展一套体外预应力结构预应力全寿命监测方法和技术，揭示体外预应力结构预应力全寿命演化规律，提出一种方便适用的体外预应力结构安全评定方法。

随着无粘结钢绞线和加固工程两项技术的发展，体外预应力结构的研究和应用已经逐渐成为土木工程界的热点问题。预应力筋作为体外预应力结构中的关键受力部件，其受力性态和实际预应力的大小对体外预应力结构的正常服役功能和安全性起到关键作用。针对现阶段满足实际工程需要的预应力监测手段匮乏这一土木工程界难题，本项目将光纤传感技术与体外预应力结构常用钢绞线相结合研制兼具受力与传感特性、集结构材料和功能材料于一体的无粘结智能传感探头，发展相应的体外预应力结构预应力监测方法和技术，探讨体外预应力结构全寿命预应力演化规律及其安全评定方法。最后，将上述技术应用于已经明确的实际工程，建立示范系统。研究结果表明：以光纤布里渊应变传感技术为主，光纤布拉格光栅应变传感技术和力学传感器为合理补充的全尺度预应力损失全寿命监测方法理论清楚、直观，易于实现；光纤光栅穿心式压力传感器具有测试精度高（测试总精度为1.62%）、抗干扰能力强、灵敏度高和长期稳定性好等诸多优点；智能钢绞线具有满足实际工程长期监测需要的几何（直径为15.12mm）、力学（1660MPa）和传感性能（测试总精度约为2.67％）。智能钢绞线可采用与普通钢绞线相同的布设工艺、张拉仪器、锚固设备，施工简单方便；通过智能钢绞线内光纤传感器能够准确监测预应力混凝土结构预应力全寿命演化规律，获得有效预应力值；与传统监测用传感器相比，准确率相当，但稳定性和成活率明显占优；给出的安全评估方法物理意义明确、方法简单直观；并且最终通过一个实际的示范工程验证了项目中的体外预应力结构健康监测与安全评定方法的有效性和优越性。.通过上述研究，发展一套体外预应力结构预应力全寿命监测方法和技术，揭示体外预应力结构预应力全寿命演化规律，提出一种方便适用的体外预应力结构安全评定方法。该方法具有广阔的应用前景。