【作者】 孙全胜；

【导师】 王克奇；

【作者基本信息】 东北林业大学 ， 机械设计及理论， 2005， 博士

【摘要】 随着国内外大跨度桥梁的增多,桥梁结构型式的轻柔化、系统功能的复杂化以及人们对桥梁安全性与耐久性的要求越来越高。智能桥梁结构将成为未来理想的桥梁结构,智能桥梁的第一层次即桥梁结构健康监测已经成为国内外工程界和学术界关注的前沿课题。本文从智能材料结构的理论出发,给出了智能桥梁结构的概念,研究了桥梁结构健康监测系统和桥梁结构光纤光栅监测技术及桥梁结构监测评估方法,并成功地应用于芜湖长江大桥斜拉桥健康监测中。 研究首先从智能材料结构的理论出发,提出了智能桥梁结构的概念,在详细阐述智能桥梁结构的组成和设计准则的基础上,讨论了智能桥梁结构的信息处理、智能类型和设计方法,指出光纤传感器是现阶段最适合智能桥梁结构的感知材料、智能桥梁结构应该以嵌入式为主,桥梁结构健康监测属于智能桥梁结构的第一层次——自感知桥梁结构,智能桥梁结构的设计要遵循两大准则——功能和效益成本分析,从初步设计到试验验证要经多个反复后才能进行施工。 根据智能桥梁结构的特点,本文研究了桥梁结构健康监测系统的组成、特点、设计准则和原则、监测内容和截面及项目,总结了现阶段桥梁结构损伤评估方法,给出了斜拉桥结构健康监测系统的监测内容和主要构成。桥梁结构健康监测系统应充分利用计算机资源,在最少人工参与的条件下,考虑系统的目的、功能、投资额度和关键部位,注重监测的实时性和长期性。系统软件设计应采用虚拟仪器技术、硬件设计应标准化,监测的主要内容是荷载、环境、几何变形和结构反应。 文中根据光纤光栅传感原理,对比了强度型、干涉型和光栅波长型三种光纤传感器,指出光纤光栅更适合桥梁结构的健康监测;通过对光纤光栅的制作、结构原理以及应变和温度传感特性研究,推出光纤光栅的波长和应变(温度)成正比,经过标定后就可用于桥梁结构的健康监测。针对桥梁结构的特点,开发了埋设于混凝土的封装光纤光栅,构建了有多路光开关的光纤光栅监测系统。在探讨光纤光栅布设工艺与保护措施的基础上,成功地把5个裸光纤光栅和5个封装光纤光栅布设于正在施工的预应力混凝土箱梁中,测试了自重作用下的混凝土应变,试验表明光纤光栅测试值和理论值吻合的很好,实现了光纤光栅的绝对测量;测试了静载作用下的混凝土应变,试验表明光纤光栅测试值和电阻应变砖测试值吻合的很好,同时也说明了管式封装光纤光栅应变传感器是解决混凝土内部变形监测的理想传感元件,可用于桥梁结构的健康监测。 根据整体法进行桥梁评估存在的困难,提出了建立桥梁结构安全评价指标的局部评估方法,并在结构线弹性范围基础上,导出桥梁结构有限元计算中荷载和反应的关系,证明利用有限元理论计算可以建立桥梁结构安全评价指标。这样早期桥梁结构安全评价指标可以利用理论计算,远期桥梁结构安全评价指标可以利用人工神经网络和自身监测数据得到,并在研究人工神经网络原理的基础上,建立斜拉桥结构的温度和索力关系的神经网络模型。 根据芜湖长江大桥斜拉桥健康监测系统功能,研究了系统监测内容、测点的布置、更多还原

【Abstract】 With the increase of large-span bridges domestic and abroad, the demands for the lightweight bridge structures, the complexity of systems, safety and durability of bridges, are gradually raised. For these reasons, intelligent bridges will become the ideal bridge structures in future. The first step of "intelligent bridge", namely bridge structure health monitoring systems, has become the foremost research area concentrated on by researchers in the fields of engineering and academia. This dissertation introduces the theory of intelligent material structure, presents the concept of intelligent bridge structure, and studies bridge structure health monitoring system and bridge structure fiber bragg grating (FBG) technique, as well as the method of bridge structure monitoring evaluation. At last we apply these techniques to the cable-stayed bridge health monitoring in Wuhu Yangtse River Bridge successfully.The theory of intelligent material structure is introduced firstly, and the concept of intelligent bridge structure is presented. Based on the detailed explication of intelligent bridge structure composing and designing rules, we discuss information processing, intelligent types and design methods. We also point out that optical fiber sensor is the optimum sensor that fits for intelligent bridge structure, and intelligent bridge structure should take priority of embedded objects. Bridge structure health monitoring belongs to the first step of intelligent bridge structure, namely self-sense bridge structure. The design of intelligent bridge structure should follow two rules: function and benefit-cost analysis, which need many trials to carry on construction from the original design to the experimental test.According to the characteristics of intelligent bridge structure, the paper studies the composition, characteristics, design rules and principles, monitoring contents, sections and items about bridge structure health monitoring system. It summarized Bridge structure damage evaluation method at present and presents monitoring content and major composition of cable-stayed bridge health monitoring system. The system should make the best use of computer resources in the condition of the least artificial participation, consider its object, function, investment and key position, pay attention to realtime and long-term characteristics of monitoring. The paper also points out that software design should adopt virtual instrument technique, hardware design should be standardized, and the major monitoring content consists of the load and environment monitoring, geometrical deformation monitoring, and structure reaction of static load monitoring.According to the principle of FBG, the dissertation contrasts the three optical fiber sensor: intensity type, interference type and grating wavelength type, and conclude that FBG is better suited for bridge structure health monitoring. Through the research on the facture , structure principle, strain and temperature characteristics of fiber bragg grating, we find that the wavelength of FBG is proportional to the strain (temperature) and it can be applied to bridge structure health monitoring after calibration. Owing to the characteristics of bridge structure,we develop the pile packaged FBG embedded in concrete and construct FBG monitoring system with multiplex optical switches. Based on the FBG location technique and protection measure, 5 packaging FBG sensors and 5 bare FBG sensors are embedded successfully in the prestress concrete box girder, that the strain of concrete under the action of dead load is tested. Experimental result shows that the test value of FBG accords with the desired value very well and the absolute measurement of FBG is achieved. The strain of concrete under the action of static load is also tested, which shows that the test value of FBG accords with that of electric strain gauges very well and explains that the pile packaged FBG strain sensor which can be applied to bridge structure health monitoring is an ideal sensor element to solve the problem of the concrete inner deformation monitoring.According to the difficulties in the bridge evaluation of integral method, we put forward a local evaluation method that establishes a bridge structure safety evaluation index. On the foundation of structural linear elasticity, the relationship between load and reaction in the calculation of finite element for bridge structure is deduced and that using finite element calculation can establish bridge structure safety evaluation index is proved. In this way, the forepart bridge structure safety evaluation index can be calculated by theory, and the long-dated can be established by artificial neural network (ANN) and auto-monitoring data. Based on the research of ANN principle, ANN model for the relationship between temperature and cable tension force in the cable-stayed bridge is also established.According to the function of cable-stayed bridge health monitoring system in Wuhu Yangtse River Bridge, monitoring contents, measuring sites, software and hardware and data transmission techniques are researched, the running results of which system are obtained. Finally, we apply FBG monitoring technique to health monitoring system in Wuhu Yangtse River Bridge, then contrast the test value of FBGs with the test value of strain gauges. Experimental results show that FBG measuring has high performance on stability and reliability. Emulation model of temperature and cable tension force established by ANN is attempted. From the forecast of 23 groups of data, it can be seen that the forecast value accords with actual value very well, which proved the feasibility of using ANN to establish bridge structure safety index successfully.更多还原