预应力混凝土箱梁桥纵向预应力对顶板的横向影响研究

发布时间：2018-03-31 01:17

本文选题：箱梁　切入点：泊松效应　出处：《湖南科技大学》2014年硕士论文

【摘要】：预应力混凝土箱梁桥发展至今，已成为最常用的一种桥梁结构，然而在箱梁中却普遍存在着开裂现象，很多设置了横向预应力的箱梁桥仍然产生顶板纵向裂缝，这表明横向预应力的设置并没有达到设计时的预期效果。研究纵向预应力在泊松效应作用下对顶板产生的横向影响，以及横向预应力受腹板框架效应产生的削弱作用，对预防顶板纵向裂缝具有一定指导意义。本文主要针对泊松效应和框架效应对顶板的横向受力影响，应用Midasfea有限元软件以陡下大桥为工程背景建立实体模型进行分析。通过张拉顶板横向不同位置的纵向预应力束来研究泊松效应在顶板产生的横向影响，以及横向应力的分布规律；通过张拉腹板竖向不同位置纵向预应力束来研究在框架效应和泊松效应共同作用下顶板产生的横向影响和横向应力的分布规律。同时，按照陡下大桥实际图纸计算了0#块到跨中合拢段纵向预应力张拉沿纵向对顶板中心的累加横向应力，，研究纵向预应力的累计效应，分析了累计效应所产生横向应力的分布规律。最后，研究了横向预应力在腹板框架效应下受到的的削弱作用，并结合箱梁自重，车辆荷载及纵向预应力三者产生的顶板横向应力分析了横向预应力的储备应力值能否抵抗顶板的纵向裂缝产生，对横向预应力的布置和设计及纵向裂缝的预防提出了建议。
[Abstract]:With the development of prestressed concrete box girder bridge, it has become one of the most commonly used bridge structures. However, there is generally cracking phenomenon in the box girder. Many box girder bridges with transverse prestressing force still produce longitudinal cracks on the roof.This indicates that the lateral prestressing force has not achieved the desired effect in the design.The study of the transverse influence of longitudinal prestress on roof under Poisson effect and the weakening effect of transverse prestress by web frame effect have certain guiding significance to prevent the longitudinal crack of roof.In this paper, aiming at the influence of Poisson effect and frame effect on the transverse force on the roof, Midasfea finite element software is used to establish the solid model of the steep-down bridge as the engineering background.The transverse effect of Poisson effect on the roof and the distribution of transverse stress are studied through the longitudinal prestressing of different transverse position of the tensioned roof.The transverse effect of roof and the distribution of transverse stress are studied by means of vertical longitudinal prestressing in different positions of web tensioning under the joint action of frame effect and Poisson effect.At the same time, according to the actual drawing of steep-down bridge, the accumulated transverse stress of longitudinal prestressing tensioning along the longitudinal side of roof center is calculated, and the accumulative effect of longitudinal prestress is studied.The distribution of transverse stress caused by accumulative effect is analyzed.Finally, the weakening effect of transverse prestress under web frame effect is studied, and combined with the weight of box girder,The lateral stress of roof caused by vehicle load and longitudinal prestressing is analyzed. Whether the reserve stress of transverse prestress can resist the longitudinal crack of roof is analyzed, and some suggestions on the arrangement and design of transverse prestress and the prevention of longitudinal crack are put forward.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441;U448.35

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