大悬臂箱梁横向预应力长期性能及配置方式研究

发布时间：2018-12-09 12:02

【摘要】：近年来,随着城市交通的发展,普通箱梁桥已难以满足交通需求,越来越多的预应力混凝土连续梁桥采用大悬臂箱形截面。在大悬臂箱梁桥中,为避免箱梁顶板出现裂缝,箱梁的顶板往往会布置横向预应力钢筋。桥梁在使用阶段由于荷载的反复作用造成混凝土的老化,从而引起横向预应力损失增大,对其安全性产生威胁。本文以某大悬臂连续箱梁为工程背景,运用ANSYS软件建立空间模型,并结合应力试验和预应力损失试验,对大悬臂连续箱梁的横向预应力长期性能和配置方式进行研究,具有一定的理论价值及工程现实意义。主要工作和成果如下:1、使用ANSYS软件建立空间实体有限元模型,并结合应力试验进行对比分析,验证大悬臂箱梁桥模型的准确性。2、对大悬臂箱梁进行横向预应力损失试验,结合理论计算值,评估箱梁的预应力损失情况。结果表明:预应力损失试验值较设计值偏大,管道成孔质量有待提高。3、结合预应力损失试验,分析横向预应力的损失对桥梁结构的影响。结果表明:若桥面横向预应力损失过大,则在桥梁的运营过程中桥面可能会出现拉应力,影响结构的抗裂性和整体性。4、分析了不同的横向预应力配置方式对箱梁受力特性的影响,提出了合理的预应力配置方式。
[Abstract]:In recent years, with the development of urban traffic, it is difficult for ordinary box girder bridge to meet the traffic demand. More and more prestressed concrete continuous beam bridges adopt large cantilever box section. In large cantilever box girder bridge, in order to avoid cracks in the top plate of box girder, transverse prestressed reinforcement is often arranged on the top of box girder. The aging of concrete caused by repeated loads in the service stage of the bridge causes the loss of transverse prestress to increase and the safety of the bridge is threatened. In this paper, taking a large cantilever continuous box girder as the engineering background, using ANSYS software to establish a spatial model, and combining with stress test and prestress loss test, the long-term performance and configuration of transverse prestressing of large cantilever continuous box girder are studied. It has certain theoretical value and engineering practical significance. The main work and achievements are as follows: 1. The finite element model of space entity is established by using ANSYS software, and the accuracy of the model of large cantilever box girder bridge is verified by comparing and analyzing with stress test. 2. The transverse prestressing loss test of large cantilever box girder is carried out, and the prestressing loss of box girder is evaluated with the theoretical calculation value. The results show that the test value of prestress loss is larger than the designed value, and the quality of pipeline hole needs to be improved. 3. Combined with the test of prestress loss, the influence of transverse prestress loss on bridge structure is analyzed. The results show that if the transverse prestressing loss of the bridge deck is too large, the bridge deck may appear tensile stress during the operation of the bridge, which will affect the crack resistance and integrity of the structure. 4. This paper analyzes the influence of different transverse prestress allocation modes on the mechanical characteristics of box girder, and puts forward a reasonable prestress configuration mode.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.213;U445.57

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