节段预制拼装混凝土桥墩静力行为研究

发布时间：2018-02-08 21:22

本文关键词： 节段预制拼装墩静力试验破坏特征有限元分析设计优化　出处：《北京交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：为了缓解大城市交通量增加而导致的交通拥堵路况,增建城市高架桥梁是一种有效手段。节段预制拼装墩作为桥梁的下部结构,具有施工快速、对既有交通影响小等特点,在近年来备受国内外关注。预制节段之间连接构造与整体式结构相比,存在一些不确定性,影响了这种结构在实际施工中的应用。针对节段预制拼装墩进行试验及理论研究十分必要。本文进行了2个节段预制拼装混凝土桥墩模型的静载试验并进行了数值模拟分析,主要工作和相关结论如下： 1.进行了节段预制拼装混凝土桥墩模型静载试验,得到了墩顶水平荷载-位移曲线及相关应变数据,详细记录了试件破坏过程。利用简化力学模型和基于平截面假定的横截面双向受弯计算程序,对试验数据进行分析。理论分析表明,模型墩的破坏始于墩底素混凝土薄弱面受拉区的受弯裂缝,最终破坏为受压区混凝土压碎,破坏过程中构件发生了以墩底受压边缘为转轴的刚体运动。 2.使用结构有限元分析软件ABAQUS对节段拼装模型墩进行了数值模拟,将计算结果与试验数据进行了对比分析。结果表明,在模型受力全过程中胶黏层材料的应力状态始终处于弹性阶段,接缝处的开裂破坏实际上为与之相近的素混凝土开裂,预制节段中的钢筋对结构整体开裂荷载及极限承载力贡献较少。 3.进行了墩柱受力行为的简化理论分析。讨论了墩底受压区塑性铰的形成,编制了MATLAB程序进行了模型受弯全过程分析。 4.研究了墩顶竖向荷载大小对节段拼装墩受力行为的影响。数值模拟计算结果表明,随着竖向力增大结构整体的开裂荷载和极限承载力均增大,但竖向力增长到一定程度时,结构破坏由弯曲破坏转变为压、弯、剪三者共同作用下的复杂破坏。 5.基于前述试验及数值模拟研究,提出了3种改善节段预制拼装桥墩受力行为的构造措施：(1)钢筋伸入连接键位中；(2)钢筋伸入键位同时增加连接键位高度；(3)连接键位布置于节段周边。有限元分析结果表明,三种改进方案均能使结构整体开裂荷载与极限承载力提升,并且使结构延性增加。 6.论文进行了节段拼装墩截面抗弯承载力计算方法的初步探讨。
[Abstract]:In order to alleviate the traffic congestion caused by the increase of traffic volume in large cities, it is an effective means to build more urban elevated bridges. As the substructure of the bridge, the precast piers are constructed quickly and have little influence on the existing traffic. In recent years, much attention has been paid at home and abroad. There are some uncertainties in connection construction between prefabricated segments and integral structures. The application of this structure in practical construction is affected. It is necessary to carry out experiments and theoretical studies on segmental precast assembled piers. In this paper, static load tests of two segmental precast assembled concrete pier models are carried out and numerical simulation analysis is carried out. The main work and related conclusions are as follows:. 1. The static load test of precast precast concrete pier is carried out, and the horizontal load-displacement curve and related strain data are obtained. The failure process of the specimen is recorded in detail. The test data are analyzed by using the simplified mechanical model and the calculation program based on the assumption of plane cross section. The failure of the model pier begins with the flexural crack in the tensile area of the weak surface of plain concrete at the bottom of the pier, and the ultimate failure is the crushing of the concrete in the compression zone. During the failure process, the rigid body movement with the compression edge of the pier bottom as the rotation axis occurs. 2. The finite element analysis software ABAQUS is used to simulate the segmental assembly model piers, and the calculated results are compared with the experimental data. The results show that, The stress state of the adhesive layer material is always in the elastic stage during the whole process of the model loading, and the cracking failure at the joint is actually similar to the plain concrete cracking. The steel bars in the precast segment contribute little to the overall cracking load and ultimate bearing capacity of the structure. 3. The simplified theoretical analysis of the stress behavior of the pier column is carried out, the forming of plastic hinge in the compression zone of the pier bottom is discussed, and the MATLAB program is compiled for the analysis of the whole bending process of the model. 4. The influence of the vertical load on the behavior of the pier is studied. The numerical simulation results show that the cracking load and ultimate bearing capacity of the whole structure increase with the vertical force increasing, but the vertical force increases to a certain extent. The structural failure is changed from bending failure to complex failure under the combined action of compression, bending and shear. 5. Based on the foregoing experimental and numerical simulation studies, In this paper, three kinds of structural measures to improve the behavior of precast assembly piers are put forward: 1) the steel bar is extended into the connecting key position and the joint height is increased at the same time, the connection key position is arranged around the segment. The finite element analysis results show that the steel bar is placed in the connection key position, and the finite element analysis results show that the finite element analysis results show that the finite element analysis shows that the finite element analysis shows that. The three improved schemes can increase the cracking load and ultimate bearing capacity of the whole structure and increase the ductility of the structure. 6. The calculation method of section flexural bearing capacity of segmental assembly pier is discussed in this paper.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441;U443.22

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