PC箱梁桥施工及成桥剪力滞特性研究

发布时间：2018-03-08 10:30

本文选题：连续梁　切入点：剪力滞效应　出处：《湖南科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：大跨径预应力混凝土箱形连续或刚构桥多采用自平衡施工工艺,其刚度和荷载随着悬臂施工进程逐步形成,因此剪力滞效应必须考虑施工过程的累积效果。与此同时,目前剪力滞的研究多数没有考虑荷载横向作用位置产生的影响。本文旨在对PC箱梁桥自平衡施工累计剪力滞效应以及成桥汽车荷载横向变位对剪力滞特性的影响进行系统的理论分析和实测研究。通过理论、实测以及有限元对比分析,得到的主要内容和成果如下:1、采用广义力与广义位移的概念,对箱梁顶板、悬臂板、底板分设不同的剪力滞广义纵向位移,采用二次抛物线作为翼板的翘曲位移函数,运用能量变分原理,建立了箱梁剪力滞控制微分方程。算例分析显示荷载横向变位对箱梁剪力滞效应基本没有影响,而对承载位置的纵向应力分布影响很大。2、基于腹板剪切变形修正箱梁剪力滞翘曲位移函数,统一全截面广义位移,运用能量变分法建立箱梁弯曲剪力滞控制微分方程。以微分方程的齐次通解为一维剪力滞梁段单元的位移模式,建立了单元刚度方程,演算了单元刚度矩阵与荷载列阵计算式,在此基础上采用Fortran语言编制了计算程序,建立了一种考虑腹板剪切变形的剪力滞效应有限梁段模型。算例分析表明考虑腹板剪切变形的单剪滞位移算法比按传统铁木辛柯梁考虑平均剪切变形的三剪滞位移算法的精度高,特别是使得主梁变形更加接近块体元模型。3、通过有限梁段模型、Midas FEA块体元模型以及现场采集的试验数据分析,归纳出连续梁施工过程剪力滞效应的一般规律以及汽车荷载横向变位对箱梁剪力滞产生的影响,验证了理论算法在工程实际运用中的准确性和可操作性。
[Abstract]:Long span prestressed concrete box continuous or rigid frame bridges adopt self-balanced construction technology, and their stiffness and load are gradually formed with the cantilever construction process, so the effect of shear lag must be taken into account in the process of construction. At present, most of the researches on shear lag do not take into account the influence of the transverse position of load. The purpose of this paper is to study the accumulative shear lag effect of PC box girder bridge in self-balance construction and the influence of the lateral displacement of vehicle load on shear lag characteristic of the bridge. To carry out systematic theoretical analysis and practical research. The main contents and results obtained are as follows: 1. By using the concept of generalized force and generalized displacement, different shear lag generalized longitudinal displacements of box girder roof plate, cantilever plate and bottom plate are established. The quadratic parabola is used as the warping displacement function of the wing plate, and the governing differential equation of the box girder shear lag is established by using the energy variational principle. The analysis of the example shows that the lateral displacement of the load has no effect on the shear lag effect of the box girder. However, the longitudinal stress distribution of the bearing position is greatly affected. Based on the web shear deformation, the shear lag warpage displacement function of the box girder is corrected, and the generalized displacement of the whole section is unified. The differential equation of bending shear lag control of box girder is established by energy variational method. The element stiffness equation is established by taking the homogeneous general solution of differential equation as the displacement model of one-dimensional shear lag beam, and the element stiffness matrix and load matrix are calculated. On this basis, the calculation program is compiled by using Fortran language. In this paper, a finite beam segment model with shear lag effect considering web shear deformation is established. An example analysis shows that the single shear lag displacement algorithm considering web shear deformation is better than the traditional Timuxinko beam with three shear hysteretic positions considering average shear deformation. The accuracy of the shift algorithm is high, In particular, the deformation of the main beam is closer to that of the block element model. 3. Through the finite beam segment model, the Midas FEA block element model and the experimental data collected in the field are analyzed. The general law of shear lag effect during construction of continuous beam and the influence of lateral displacement of vehicle load on shear lag of box girder are summarized. The accuracy and maneuverability of the theoretical algorithm in engineering practice are verified.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441;U448.213

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