行车荷载作用下混凝土曲线箱梁剪力滞效应研究

发布时间：2018-04-16 07:47

本文选题：行车荷载 + 曲线桥　；参考：《武汉工程大学》2014年硕士论文

【摘要】：曲线箱梁是一种常见的桥梁结构形式。它不仅能够满足各个方向的交通连接，也能实现公路线形的要求，其截面形式还能满足预应力混凝土结构的空间部署以及各类管线等公共设施的安装的需要。此外，箱型截面自重轻、截面抗弯和抗扭刚度大的优点使箱型梁在施工和使用过程中具有非常好的稳定性，其顶板和底板具有足够的混凝土面积，能够有效地满足配筋的要求，因此在桥梁结构工程中被广泛应用。然而，在箱梁中，由于剪切变形沿箱梁翼缘板宽度非均匀分布会引起剪力滞效应，从而对桥梁的安全造成一定的影响。工程实践证明，对剪力滞效应的忽略，是造成一些重大工程事故的主要原因。目前，静荷载作用下截面形式相对比较简单的曲线箱梁剪力滞效应已经进行了大量充分研究，取得了一些研究成果；在静荷载作用下的曲线箱梁剪力滞效应除了具备一般直线箱梁剪力滞效应的一般规律外，由于曲线箱梁截面形式及受力状况的复杂性，使其更具有特殊性，在一定程度上也会加剧剪力滞效应的影响。对于动荷载作用下曲线箱梁的剪力滞效应，还少有研究成果。为此，本文以简支曲线箱梁为研究对象，采用大型通用三维有限元软件ANSYS，分析了曲线箱梁在行车荷载作用下的剪力滞效应。主要内容有：（1）行车荷载的数值模拟。从动荷载作用下桥梁的动力响应出发，，提出既能对曲线箱梁剪力滞效应进行分析，又能使用有限元方法进行分析计算的荷载模型。在有限元分析中，将行车荷载简化为四个点荷载沿着顶板与腹板交接线运动。（2）曲线箱梁行车荷载作用下不同结构参数对剪力滞效应的影响规律。通过采用有限元方法，利用ANSYS软件，建立行车荷载作用下简支曲线箱梁分析模型，分析了箱梁高度h、腹板厚度t、曲率半径r与腹板间距d等参数对简支曲线箱梁剪力滞效应的影响规律，总结出在各种不同的结构参数影响下曲线箱梁剪力滞效应的变化规律。结果表明，几个参数对曲线箱梁剪力滞效应都有影响，影响大小各不相同，而箱梁高度h的对曲线箱梁剪力滞效应的影响最明显。（3）探讨了不同的行车荷载速度对简支曲线箱梁剪力滞效应的影响变化。采用五种不同的行车速度，速度由静止逐渐加倍，即由0m/s变化到8m/s，研究不同速度的变化对曲线箱梁在同一行车荷载作用下产生的剪力滞效应的影响，得到简支曲线箱梁在行车荷载作用下不同的速度对剪力滞效应的影响变化。结果表明，当行车荷载速度在0~6m/s之间时，外侧的剪力滞系数逐渐增加，内侧的剪力滞系数逐渐减小；当行车荷载速度超过6m/s时，外侧的剪力滞系数开始减小，内侧的剪力滞系数开始增加，速度对曲线箱梁剪力滞效应的影响比较明显。（4）探讨了不同的行车荷载作用位置对简支曲线箱梁剪力滞效应的影响。在通常采用的荷载作用位置的基础上，即荷载沿着顶板与腹板交接线移动，增加另外的两种不同荷载作用位置，分别是：行车荷载分别靠近内侧移动与靠近外侧移动，在有限元模型中为分别向内侧和外侧移动两个网格距离。通过三种不同的荷载作用位置，对比行车荷载作用位置分别由外侧向内侧移动这三种情况下曲线箱梁的剪力滞效应变化情况。分析表明荷载作用位置对曲线箱梁剪力滞效应的影响非常明显。（5）曲线箱梁与直线箱梁剪力滞效应的对比分析。曲线箱梁结构参数化分析结果显示，曲线箱梁高度对剪力滞效应影响最为明显，因而设置三种不同箱梁高度建立有限元模型，分析了简支曲线箱梁和简支直线箱梁在1/4L、1/2L、3/4L横截面位置处，顶板的应力分布随高度变化的规律及内外侧的剪力滞系数变化特征，结果表明在顶板与腹板的两条交接线位置处，简支曲线箱梁的外侧剪力滞系数大于内侧的剪力滞系数，简支直线箱梁交接处的剪力滞系数处于两者之间，1/4L与3/4L顶板横截面处的应力分布较为类似，而1/2L横截面处的应力分布与1/4L和3/4L横截面处的应力分布非常不同，1/2L处应力曲线更为平缓。
[Abstract]:Curved box girder is a kind of common bridge structure form . It can not only meet the traffic connection in all directions , but also can meet the requirement of highway alignment .
In addition to the general rule of shear lag effect of curved box girder under the action of static load , the shear lag effect of curved box girder under the action of driving load is analyzed .

( 1 ) Numerical simulation of the driving load . Based on the dynamic response of the bridge under the action of dynamic load , this paper puts forward the load model which can not only analyze the shear lag effect of the curved box girder , but also can use the finite element method to analyze the load model . In the finite element analysis , the driving load is simplified into four point loads along the joint line between the top plate and the web .

( 2 ) The influence of different structural parameters on the shear lag effect of the curved box girder under the action of driving load of the curved box girder is analyzed . The influence of the parameters on the shear lag effect of the curved box girder under the influence of various structural parameters is analyzed . The results show that the effect of several parameters on the shear lag effect of the curved box girder is different , and the influence of the height h of the box girder on the shear lag effect of the curved box girder is most obvious .

( 3 ) The effect of different driving load speed on the shear lag effect of simply supported curved box girder is discussed . The influence of different speeds on the shear lag effect of the curved box girder under the same driving load is studied by means of five different driving speeds . The results show that the shear lag coefficient of the curved box girder increases gradually and the shear lag coefficient of the inner side decreases gradually when the driving load speed is between 0 and 6m / s .
When the speed of driving load exceeds 6m / s , the shear lag coefficient of the outer side starts to decrease , the shear lag coefficient of the inner side starts to increase , and the effect of the speed on the shear lag effect of the curved box girder is obvious .

( 4 ) The influence of different load acting positions on the shear lag effect of the simply supported curved box girder is discussed . In this paper , the load acting on the basis of the load acting position , i.e . the load is moved along the boundary between the top plate and the web , and the other two different loading positions are added .

( 5 ) The shear lag effect of the curved box girder and the straight box girder is analyzed . The results of the parametric analysis of the curved box girder show that the shear lag coefficient of the curved box girder is most obvious to the shear lag effect , and the stress distribution of the top plate is similar to that of the inner lateral shear lag coefficient at the position of 1 / 4L , 1 / 2L and 3 / 4L . The stress distribution at the intersection of the simple supported curved box girder is very similar with the stress distribution at the cross section of 1 / 4L and 3 / 4L , and the stress curve at 1 / 2L is more gradual .

【学位授予单位】：武汉工程大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441;U448.213

【共引文献】