预应力混凝土梁桥剩余使用寿命预测

发布时间：2018-03-17 23:14

本文选题：预应力混凝土梁桥　切入点：抗力衰减　出处：《郑州大学》2014年硕士论文　论文类型：学位论文

【摘要】：预应力混凝土梁桥是大跨径桥梁常用的桥型，由于建造桥梁所用的建筑材料自身存在缺陷和不足，在桥梁运营阶段又要承受荷载等动力作用和自然环境侵蚀，必然会导致桥梁结构性能衰减，造成桥梁耐久性和承载能力不足。因此，研究预应力混凝土梁桥剩余使用寿命，可以为桥梁维修加固决策提供依据，具有重要的实用价值和理论意义。本文以郑少高速公路航海路连接线南水北调大桥辅线桥（以下简称辅线桥）为工程实例，研究造成预应力混凝土梁桥抗力衰减因素，预测桥梁剩余使用寿命，主要完成以下工作： 1.论述了引起钢筋混凝土梁桥以及预应力混凝土梁桥抗力衰减的因素，选择了混凝土碳化预测模型、钢筋锈蚀预测模型、混凝土强度变化模型和基于钢筋锈蚀的结构抗力衰减模型。 2.论述了规范中桥梁恒载、设计基准期与评估基准期内车辆荷载效应最大值的统计分析方法、荷载分布模型和参数估计；给出了车辆冲击荷载效应的计算方法和人群荷载的统计规律。 3.探讨了混凝土梁桥碳化寿命、锈胀开裂寿命和承载能力寿命终结的判定标准，为混凝土梁桥使用寿命的判定提供了依据；建立了预应力混凝土梁桥碳化寿命、锈胀开裂寿命和抗弯、抗剪承载能力寿命的极限状态方程，计算混凝土梁桥各使用寿命的可靠指标。 4.基于时变可靠度理论，计算了辅线桥主梁和桥墩混凝土碳化寿命和钢筋锈胀开裂寿命，得到辅线桥设计基准期内主梁跨中抗弯承载能力和主梁1/4跨抗剪承载能力可靠指标。计算结果表明：一般大气环境下，若辅线桥混凝土强度高，混凝土碳化和钢筋、预应力筋锈蚀就会非常缓慢，其承载能力的衰减可只考虑预应力损失和混凝土强度变化这两种因素，，在此种情况下，辅线桥设计基准期内的抗弯承载能力能够得到保证；只考虑碳化作用引起的钢筋锈蚀时，辅线桥抗剪承载能力在设计基准期内能够满足要求。
[Abstract]:Prestressed concrete beam bridge is a commonly used bridge type in long-span bridges. Because of the defects and shortcomings of the building materials used in the construction of bridges, it has to bear dynamic effects such as loads and natural environment erosion in the operation stage of bridges. Therefore, the study of residual service life of prestressed concrete beam bridge can provide the basis for bridge maintenance and reinforcement decision. It is of great practical value and theoretical significance. In this paper, taking the auxiliary line bridge of the South-to-North Water transfer Bridge (hereinafter referred to as the auxiliary line bridge) as an engineering example, the factors causing the attenuation of the resistance of the prestressed concrete girder bridge are studied. To predict the remaining service life of the bridge, the following work will be accomplished:. 1. The factors that cause the resistance attenuation of reinforced concrete beam bridge and prestressed concrete beam bridge are discussed. The prediction model of concrete carbonization and the prediction model of steel corrosion are selected. Concrete strength change model and structural resistance attenuation model based on steel bar corrosion. 2. The statistical analysis method, load distribution model and parameter estimation of the maximum value of vehicle load effect in the reference period, design reference period and evaluation period in the code are discussed. The calculation method of vehicle impact load effect and the statistical law of crowd load are given. 3. The criterion of carbonation life, rust expansion cracking life and bearing capacity life of concrete beam bridge is discussed, which provides the basis for the determination of concrete beam bridge service life, and establishes the carbonation life of prestressed concrete beam bridge. The ultimate state equations of the life of corrosion expansion cracking and bending and shear bearing capacity are used to calculate the reliable indexes of the service life of concrete beam bridges. 4. Based on the time-varying reliability theory, the carbonation life of main girder and pier of auxiliary bridge and the life of corrosion cracking of steel bar are calculated. The reliability indexes of the flexural bearing capacity of the main girder and the shear bearing capacity of the 1/4 span of the main beam during the design reference period of the auxiliary bridge are obtained. The calculation results show that if the concrete strength of the auxiliary line bridge is high, the concrete carbonization and reinforcement are obtained. The corrosion of prestressed tendons will be very slow, and the attenuation of its bearing capacity can only take into account the loss of prestress and the change of concrete strength. In this case, the flexural bearing capacity of auxiliary bridges can be guaranteed during the design reference period. Considering only the corrosion of steel bar caused by carbonation, the shear bearing capacity of the auxiliary bridge can meet the requirements in the design reference period.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.35;U441

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