高墩连续刚构桥刚度与开裂分析

发布时间：2018-02-04 10:11

本文关键词： 连续刚构桥开裂刚度数值分析静载试验　出处：《东北林业大学》2014年硕士论文　论文类型：学位论文

【摘要】：连续刚构桥在运营过程中普遍存在主梁开裂的问题,裂缝的产生与增长会造成主梁截面刚度和连续刚构桥整体刚度的降低,从而致使主梁跨中下挠,下挠又不断促进裂缝发展,两者相互耦合。目前,对于开裂与刚度对桥梁结构的影响及两者相互影响的研究较少,对在役多跨连续刚构桥开裂与刚度的分析成为一个亟待解决的问题。本文主要借助于有限元程序所具有的强大建模及分析功能,结合实桥开裂调查与静载试验,通过模拟计算的方法对多跨连续刚构桥开裂和刚度进行定量分析。首先,对多跨连续刚构桥主梁开裂及下挠基本理论进行介绍和分析；介绍箱梁结构的空间受力状态,以及箱梁受力状态的分析方法；接着介绍箱梁开裂的基本理论,包括裂缝产生的机理、预应力箱梁裂缝分类和箱梁开裂影响因素；又阐述了结构下挠机理、相关计算公式和挠度产生原因；为后续相关敏感性分析和开裂、挠度相互作用关系提供理论基础。在后续研究中分别通过各因素不同取值时主梁应力和挠度变化来分析其对结构开裂和刚度的影响。其次,本文依托实际工程红岭高架桥,对该五跨连续刚构桥进行了简要的工程概况介绍,利用Midas/Civil进行了空间梁元仿真分析,利用Ansys对0号块受力复杂部位进行局部实体分析；红岭高架桥为高墩连续刚构桥,墩梁刚度比决定内力分配,又因连续刚构桥为超静定结构,温度引起的附加内力在设计中所占比重很大,因此进行了预应力损失、墩身刚度以及温度梯度对主梁开裂和刚度的影响分析。再次,设定统计参数,对红岭高架桥三次裂缝调查进行统计,并分析裂缝开裂现状及发展规律；利用平面刚架模型对斜裂缝进行模拟,参照裂缝统计结果,分析多跨预应力混凝土刚构桥不同开裂位置以及裂缝相关参数对主梁刚度影响；采用平面刚架模型对三次开裂状态进行计算,分析三次调查中该桥受力状态及刚度折减情况；根据实桥开裂后刚度折减情况,研究了刚度降低对主梁开裂与下挠的影响。最后,为了验证红岭高架桥开裂状态下的实际承载能力与刚度,对该桥进行了静载试验。详述了该桥静载试验的试验方案,又利用空间梁单元模型计算出在设计荷载作用下各控制截面的应力和挠度的理论值,将各测试工况中控制断面的实测应变值和挠度值进行数据处理,同理论计算值进行比较,根据校验系数评定红岭高架桥的实际承载能力和现存刚度。
[Abstract]:Continuous rigid frame bridge in the operation process generally exists in the main beam cracking problem, the generation and growth of cracks will lead to the main beam section stiffness and continuous rigid frame bridge stiffness of the whole reduction, thus leading to the main beam in the deflection. At present, the influence of cracking and stiffness on bridge structure and the interaction between them are less studied. The analysis of crack and stiffness of existing multi-span continuous rigid frame bridge becomes an urgent problem. In this paper, with the help of the powerful modeling and analysis function of the finite element program, combined with the crack investigation and static load test of the real bridge. The cracking and stiffness of multi-span continuous rigid frame bridge are quantitatively analyzed by means of simulation calculation. Firstly, the basic theory of crack and deflection of multi-span continuous rigid frame bridge is introduced and analyzed. This paper introduces the spatial stress state of box girder structure and the analysis method of box girder stress state. Then the basic theory of box girder cracking is introduced, including the mechanism of crack generation, the classification of prestressed box girder crack and the influence factors of box girder crack. The mechanism of structure deflection, the formula of calculation and the cause of deflection are also discussed. For subsequent correlation sensitivity analysis and cracking. The deflection interaction provides a theoretical basis for the analysis of the influence of the stress and deflection of the main beam on the cracking and stiffness of the structure under different values of various factors in the subsequent studies. Secondly, based on the actual project Hongling viaduct, this paper gives a brief introduction to the five-span continuous rigid frame bridge, and carries out the spatial beam element simulation analysis by using Midas/Civil. Ansys is used to analyze the local entity of the complex part of No. 0 block. Hongling viaduct is a continuous rigid frame bridge with high piers. The stiffness ratio of pier beam determines the distribution of internal force, and because the continuous rigid frame bridge is statically indeterminate, the additional internal force caused by temperature occupies a large proportion in the design. Therefore, the effects of prestress loss, pier stiffness and temperature gradient on the cracking and stiffness of the main beam are analyzed. Thirdly, the statistical parameters are set up to make statistics on the three cracks of Hongling viaduct, and the current situation and development law of crack cracking are analyzed. The plane rigid frame model is used to simulate the oblique cracks. According to the statistical results of the cracks, the effects of different crack positions and crack related parameters on the stiffness of the main beam of multi-span prestressed concrete rigid frame bridge are analyzed. The plane rigid frame model is used to calculate the third cracking state, and the stress state and stiffness reduction of the bridge in the three investigations are analyzed. According to the stiffness reduction of the real bridge after cracking, the effect of stiffness reduction on the cracking and deflection of the main girder is studied. Finally, in order to verify the actual bearing capacity and stiffness of Hongling viaduct under cracking condition, the static load test of the bridge is carried out, and the test scheme of the bridge static load test is described in detail. Using the spatial beam element model to calculate the theoretical values of the stress and deflection of each control section under the action of design load, the measured strain value and deflection value of the control section in each test condition are processed. The actual bearing capacity and existing stiffness of Hongling viaduct are evaluated according to the check coefficient.
【学位授予单位】：东北林业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.23

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