大跨度预应力混凝土结构应力状态监测与安全评估

发布时间：2018-04-24 10:32

本文选题：预应力混凝土结构 + 光纤传感　；参考：《大连理工大学》2013年硕士论文

【摘要】：预应力混凝土结构中钢绞线的粘结保护方法和应力状态监测一直是工程界亟待解决的问题,而普通的钢绞线及监测手段无法满足以上需求,本文在内嵌FRP智能钢绞线基础上,结合缓粘结技术工艺,开发出一种可取代普通预应力钢绞线直接布设于预应力混凝土结构中的智能部品,即缓粘结预应力智能钢绞线,并对大跨预应力混凝土结构进行了预应力状态监测及安全评估,为结构的预应力状态评价提供了借鉴与参考。主要研究内容包括以下方面：首先,分析了预应力损失影响因素及评价不确定性,提出了以预应力筋应变值作为嵌入监测目标的预应力损失直接监测法代替复杂的分项叠加计算法；分析了不同荷载下预应力混凝土结构应力状态及变形情况,采用预应力筋和混凝土控制截面应力、内力、变形作为工程实际和理论设计对比指标反映预应力设计误差,提出了以正常使用及承载能力状态下预应力混凝土结构实际内力安全系数作为评价依据的安全评估及预警方法。其次,结合内嵌FRP智能钢绞线与缓粘结工艺技术,开发了光纤布里渊型/光纤布拉格光栅型带肋缓粘结预应力智能钢绞线(S-RPSR-OF/FBG),并研究了其基本力学性能、粘结锚固性能、材料摩阻性能和相关智能监测性能等,分析得出S-RPSR-OF/FBG不仅继承了普通预应力钢绞线轴向抗拉性能强及光纤传感元件对应变和温度的感知性能,而且具有施工简单和安全可靠的缓粘结技术特点,是集受力与传感于一体的新型预应力状态监测智能部品。最后,通过将曲线形和折线形S-RPSR-OF/FBG应用于某甲类剧场建筑大跨度预应力混凝土梁、板预应力监测与安全评估工程中,得到了预应力筋损失分布规律及有效应力时变性特征,分析了预应力损失因素(κ、μ、θanιf)的实际影响效果；计算得出工程实际与理论设计指标误差及实际内力指标安全系数,实现了大跨度预应力混凝土结构的安全评估；并提出了适于工程应用的等效应力计算方法、缓粘结摩擦系数确定法及张拉控制措施,为缓粘结预应力混凝土结构设计与施工提供了参考。
[Abstract]:The bond protection method and stress state monitoring of steel strands in prestressed concrete structures have always been an urgent problem to be solved in engineering circles, but the common steel strands and monitoring methods can not meet the above needs. Based on the embedded FRP intelligent steel strands in this paper, Combining with the technology of slow bonding, a kind of intelligent part which can replace the common prestressed steel strand in the prestressed concrete structure is developed, that is, the slowly bonded prestressed intelligent steel strand. The pre-stressed state monitoring and safety evaluation of long-span prestressed concrete structure are carried out, which provides a reference and reference for the pre-stressed state evaluation of the structure. The main contents of the study include the following: Firstly, the influencing factors of prestress loss and the uncertainty of evaluation are analyzed, and the direct monitoring method of prestress loss is put forward to replace the complicated superposition calculation method with the strain value of prestressed tendons as the embedded monitoring target. The stress state and deformation of prestressed concrete structure under different loads are analyzed. The prestressed tendons and concrete are used to control the cross-section stress, internal force and deformation as the comparative indexes of engineering practice and theoretical design to reflect the design error of prestressing force. Based on the actual internal force safety factor of prestressed concrete structure under normal use and bearing capacity, the method of safety assessment and early warning is put forward. Secondly, combining with the technology of embedded FRP intelligent strand and slow bonding technology, the fiber Brillouin type / fiber Bragg grating type prestressed intelligent steel strand S-RPSR-OF / FBGG is developed, and its basic mechanical properties and bond anchoring properties are studied. The properties of material friction and related intelligent monitoring are analyzed. It is concluded that S-RPSR-OF/FBG not only inherits the axial tensile properties of common prestressed steel strands, but also the sensing properties of fiber optic sensing elements to strain and temperature. It has the characteristics of simple construction and safe and reliable slow bonding technology. It is a new intelligent part of prestressing state monitoring which integrates force and sensor. Finally, through the application of curved and folded S-RPSR-OF/FBG to the prestressed concrete beam with large span in a class A theater building, the distribution law of the loss of prestressed tendons and the time-varying characteristics of effective stress are obtained. The actual effect of the factors of prestress loss (魏, 渭, 胃 an l f) is analyzed, the error of engineering practical and theoretical design index and the safety factor of actual internal force index are calculated, and the safety evaluation of long-span prestressed concrete structure is realized. The equivalent stress calculation method, the method of determining the friction coefficient of slow bond and the tensioning control measures are put forward, which provide a reference for the design and construction of slowly bonded prestressed concrete structure.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU378;TU317

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