地锚式预应力混凝土独斜塔斜拉桥安全性能研究

发布时间：2018-12-07 14:06

【摘要】：地锚式预应力混凝土独斜塔斜拉桥是近年来逐渐发展起来的一种新型的组合体系斜拉桥。地锚式独斜塔斜拉桥其倾斜的塔身可以平衡主梁的一部分自重,使结构的受力更加合理,而且斜塔可以达到更好的景观效果。然而,这种类型的桥梁施工过程的稳定性较差,结构体系新颖,受力复杂,关于该类桥梁安全性能研究的文献相对较少,桥梁工作者急需了解地锚式独斜塔斜拉桥的受力特性和安全性能,因此,对该类桥梁的安全性能进行分析和研究是非常有必要的。本文以某地锚式预应力混凝土独斜塔斜拉桥为工程背景,通过查阅大量相关文献,对斜拉桥安全性能理论和分析方法进行了归纳和总结,采用ANAYS有限元软件建立了该斜拉桥的实体单元模型和梁单元模型,对该斜拉桥进行数值模拟分析。本文选取最大悬臂阶段和桥面二期铺装阶段作为典型的施工阶段,考虑非线性因素的影响对典型施工阶段的稳定性和极限承载力进行分析。论文研究了斜拉桥在运营阶段设计荷载作用下的受力特性,并计算了不同工况作用下斜拉桥的极限承载力,分析中考虑了汽车中载和汽车偏载的影响,得出斜拉桥的不同工况作用下的安全系数和及其破坏形式。论文选取拉索断裂、斜塔倾角、横梁间距和结构体系作为影响因素,分析不同参数对斜拉桥极限承载力的影响。研究表明:斜拉桥在施工阶段的稳定安全系数较大,安全性能良好。运营阶段在设计荷载作用下,结构的受力状态合理。考虑汽车荷载不同的布载方式,该桥在达到极限承载力时具有较大的安全系数,斜拉桥具有较大的安全储备。背塔侧的斜拉索发生断裂对斜拉桥极限承载力的影响程度要大于主跨侧斜拉索发生断裂的情况。在原斜塔倾角基础上,斜拉桥的极限承载力随斜塔倾角的减小而减小,随斜塔倾角的增大先增大后减小。横梁间距对斜拉桥承受汽车偏载作用时的极限承载力有重要影响,对于地锚式预应力混凝土独斜塔斜拉桥,应优先选用刚构体系。
[Abstract]:Ground anchor prestressed concrete single inclined tower cable-stayed bridge is a new type of composite cable-stayed bridge developed gradually in recent years. The inclined tower can balance part of the weight of the main beam, make the force of the structure more reasonable, and the inclined tower can achieve better landscape effect. However, the stability of this type of bridge during the construction process is poor, the structure system is novel, the force is complex, and the literature on the safety performance of this kind of bridge is relatively few. Bridge workers urgently need to understand the mechanical characteristics and safety performance of ground-anchored single-tower cable-stayed bridge. Therefore, it is very necessary to analyze and study the safety performance of this kind of bridge. Taking a ground anchor prestressed concrete single inclined tower cable-stayed bridge as the engineering background, this paper sums up and summarizes the theory and analysis method of the safety performance of the cable-stayed bridge by consulting a large number of relevant documents. The solid element model and beam element model of the cable-stayed bridge are established by using ANAYS finite element software, and the numerical simulation of the cable-stayed bridge is carried out. In this paper, the maximum cantilever stage and the second deck paving stage are selected as the typical construction stages, and the stability and ultimate bearing capacity of the typical construction stage are analyzed considering the influence of nonlinear factors. In this paper, the stress characteristics of cable-stayed bridge under design load in operation stage are studied, and the ultimate bearing capacity of cable-stayed bridge under different working conditions is calculated. The influence of vehicle load and vehicle bias load is considered in the analysis. The safety factor and failure form of cable-stayed bridge under different working conditions are obtained. In this paper, cable fracture, inclined tower angle, beam spacing and structure system are selected as the influencing factors to analyze the influence of different parameters on the ultimate bearing capacity of cable-stayed bridge. The results show that the stable safety coefficient of cable-stayed bridge is high and the safety performance is good. In the operation stage, the stress state of the structure is reasonable under the action of design load. Considering the different distribution modes of vehicle load, the bridge has a large safety coefficient when it reaches the ultimate bearing capacity, and a large safety reserve for the cable-stayed bridge. The influence of cable fracture on the ultimate bearing capacity of cable-stayed bridge is greater than that of main span cable. The ultimate bearing capacity of the cable-stayed bridge decreases with the decrease of the inclined angle of the inclined tower, and increases first and then decreases with the increase of the inclined angle of the inclined tower. The distance between beams has an important effect on the ultimate bearing capacity of cable-stayed bridges under the action of vehicle deflection. The rigid frame system should be preferred for the single-tower prestressed concrete cable-stayed bridges with ground anchors.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.27

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