大跨径连续刚构桥底板崩裂机理及其影响研究

发布时间：2019-01-28 06:58

【摘要】：大跨径连续刚构桥是目前使用的较为广泛的桥型之一。由于设计理论不完善、施工质量缺陷等原因,该桥型在施工和运营阶段出现病害时常发生,底板崩裂就是其中之一。底板发生崩裂的主要原因在于低估了等效径向力的大小和影响,及对抗崩设计不合理。底板崩裂后会对结构的安全性、耐久性和正常使用等均产生十分不利的影响。工程界、学术界对该类型破坏已进行了长期、大量的事故原因分析,本文在参考大量文献和借鉴前人成果的基础上,运用数学计算和有限元程序模拟两种方法,对底板崩裂机理、箱梁空间效应的影响因素、底板抗崩设计进行了分析。首先,本文对大跨径连续刚构桥预应力束的等效径向力进行了系统研究,分析了竖向曲线线型、管道定位误差及节段施工对等效径向力的影响方式及影响程度,探讨了在此三项因素下如何控制等效径向力,也在此基础上对等效径向力计算公式提出了修正;研究了底板挖空率、温度梯度效应及混凝土泊松效应对箱梁底板应力的影响,并提出了相应的建议。其次,以典型的连续刚构箱梁桥为研究对象,通过有限元模型,对底板混凝土的抗崩设计进行了分析。总结了防崩钢筋和预应力管道保护层厚度的计算公式,并通过改变背景桥梁的孔肋厚度、管道的保护层厚度及底板的厚度,比较了这些变化对底板应力的影响。最后,对云南某实桥底板崩裂的问题,其成因进行了分析,验证了本文所提出等效径向力的修正和对抗崩设计分析的合理性。通过对该桥的加固方案进行的比选,也通过对国内外箱梁桥的设计和施工经验,总结了一些经验,以供借鉴。
[Abstract]:Long span continuous rigid frame bridge is one of the most widely used bridges. Because the design theory is not perfect and the construction quality is defective, the bridge is often damaged in the construction and operation stage, among which the floor crack is one of them. The main causes of floor collapse are that the magnitude and influence of equivalent radial force are underestimated, and the design of anti-collapse is not reasonable. The collapse of the floor will have an adverse effect on the safety, durability and normal use of the structure. The engineering circle and academic circles have carried on the long-term, massive accident cause analysis to this kind of damage, this article uses the mathematical calculation and the finite element program to simulate two methods, on the basis of referring to a large number of documents and drawing lessons from the predecessor's achievement. The mechanism of floor collapse, the influence factors of box girder spatial effect, and the design of floor slab anti-collapse are analyzed. Firstly, this paper systematically studies the equivalent radial force of prestressed beam of long-span continuous rigid frame bridge, and analyzes the influence of vertical curve line, pipeline positioning error and segment construction on the equivalent radial force. This paper discusses how to control the equivalent radial force under these three factors, and puts forward a correction to the formula of the equivalent radial force on this basis. The influence of hollowness ratio of bottom slab, temperature gradient effect and Poisson effect of concrete on the stress of bottom slab of box girder are studied, and the corresponding suggestions are put forward. Secondly, taking the typical continuous rigid frame box girder bridge as the research object, through the finite element model, the anti-collapse design of the floor concrete is analyzed. The formulas for calculating the thickness of caving steel bar and prestressed pipe cover are summarized. By changing the thickness of the hole rib of the background bridge, the thickness of the protective layer of the pipeline and the thickness of the bottom slab, the effects of these changes on the stress of the bottom slab are compared. Finally, the causes of the collapse of a real bridge floor in Yunnan Province are analyzed, which verifies the rationality of the correction of the equivalent radial force and the analysis of the anti-collapse design proposed in this paper. Through the comparison and selection of the reinforcement scheme of the bridge, and through the design and construction experience of the box girder bridge at home and abroad, some experiences are summarized for reference.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.23

【参考文献】