中小跨径混凝土桥梁疲劳荷载模型及疲劳性能研究

发布时间：2018-01-23 18:40

本文关键词： 混凝土中小跨径桥梁疲劳荷载疲劳性能铰缝铰接板梁法荷载横向分布时变可靠度　出处：《浙江大学》2015年硕士论文　论文类型：学位论文

【摘要】：在当前的桥梁结构设计与维护管理中,人们往往重视钢结构的疲劳问题,而忽视混凝土结构的疲劳性能。随着交通荷载的增长,其承载力随时间退化,也会产生疲劳安全问题。尤其是像多梁式混凝土梁桥的横向连接铰缝,属于结构的薄弱部位,在环境腐蚀和疲劳荷载作用下,容易出现各类病害。本文在浙江省交通运输厅科技项目“中小跨径混凝土桥梁性能维护的关键技术及应用研究”的资助下,对衢州地区典型的国省道交通状况进行调研统计,对标准疲劳车辆模型进行了推导,同时对预应力空心板梁桥开裂机理展开研究与讨论,结合考虑铰缝抗剪刚度的铰接板梁法,对横向分布时变规律和疲劳时变可靠度进行了研究。主要研究工作及成果如下： 1)根据对衢州地区典型国省道交通状况的统计,提出了疲劳车辆荷载谱和对应的交通量；依据疲劳损伤等效原则,推导了适用于不同道路类型的标准疲劳车辆模型,具有较高的准确性和适用性,并和其他标准疲劳车辆模型进行了对比分析。 2)在标准疲劳车辆模型基础上,从静力和疲劳角度对多梁式混凝土桥梁结构开裂机理进行了分析研究,提出了基于铰缝疲劳破坏的预应力空心板梁桥寿命预测方法。结果显示在新规范静力设计荷载作用下桥面不会开裂；疲劳车辆作用下,混凝土铰缝疲劳损伤将加速结构的早期开裂；通过对疲劳影响因素的探讨,发现适当加大铺装层厚度和施加横向预应力可以提高这类结构的疲劳寿命。 3)基于混凝土、钢筋材料特性及板梁铰缝粘结刚度的劣化模型,得到环境腐蚀和疲劳作用下不同形式混凝土铰缝的抗剪刚度退化模型；通过对铰缝抗剪承载力的数值分析,发现构造较浅的混凝土铰缝的抗剪承载力远小于构造较深的混凝土铰缝,铰缝钢筋虽然对弹性阶段受力影响不大,但能显著提高构件的抗剪承载力。 4)根据得到的多梁式混凝土铰缝抗剪刚度退化模型,对桥梁横向分布影响线的时变规律进行了研究,将考虑铰缝抗剪刚度的铰接板梁法计算结果和梁格法以及有限元实体模型的分析结果进行了对比,结果吻合良好；在此基础上将有关成果进一步应用到混凝土桥梁结构疲劳时变可靠度的计算中。
[Abstract]:In the current bridge structure design and maintenance management, people often pay attention to the fatigue problem of steel structure, but ignore the fatigue performance of concrete structure. With the increase of traffic load, its bearing capacity degenerates with time. Especially the transverse joint joint of multi-beam concrete beam bridge belongs to the weak part of the structure under the action of environmental corrosion and fatigue load. This paper is supported by "key Technology and Application Research on performance maintenance of medium and small Span concrete Bridges", Science and Technology Project of Zhejiang Transportation Department. The traffic situation of typical provincial roads in Quzhou is investigated and statistics, the standard fatigue vehicle model is deduced, and the cracking mechanism of prestressed hollow slab girder bridge is studied and discussed. Combined with the hinged slab beam method considering the shear stiffness of hinged joints, the time-varying rule of transverse distribution and the time-varying reliability of fatigue are studied. The main work and results are as follows: 1) according to the traffic statistics of typical provincial roads in Quzhou, the fatigue vehicle load spectrum and the corresponding traffic volume are put forward. According to the principle of equivalent fatigue damage, the standard fatigue vehicle models suitable for different road types are derived, which have higher accuracy and applicability, and are compared with other standard fatigue vehicle models. 2) on the basis of standard fatigue vehicle model, the cracking mechanism of multi-beam concrete bridge structure is analyzed and studied from static and fatigue point of view. The life prediction method of prestressed hollow slab girder bridge based on hinge joint fatigue failure is proposed. The results show that the bridge deck will not crack under the static design load of the new code. Under the action of fatigue vehicle, the fatigue damage of concrete hinge joints will accelerate the early cracking of the structure. It is found that the fatigue life of this kind of structure can be improved by increasing the thickness of pavement and applying transverse prestressing force. 3) based on the deterioration model of concrete, steel bar material characteristics and bond stiffness of slab beam hinge joint, the degradation model of shear stiffness of different forms of concrete hinge joints under the action of environmental corrosion and fatigue is obtained. Through the numerical analysis of shear bearing capacity of hinged joints, it is found that shearing capacity of shallower concrete joints is much smaller than that of deeper concrete joints, and the reinforcement of hinged joints has little effect on the stress in elastic stage. But it can significantly improve the shear capacity of the members. 4) according to the degradation model of shear stiffness of multi-beam concrete hinge joints, the time-varying law of the influence line of bridge transverse distribution is studied. The calculation results of hinged plate beam method considering the shear stiffness of hinged joints are compared with those of the beam method and the finite element solid model, and the results are in good agreement. On this basis, the related results are further applied to the calculation of fatigue time-varying reliability of concrete bridge structures.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441.4

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