曲线连续钢箱梁剪力滞效应研究及结构受力性能分析

发布时间：2018-01-20 03:31

本文关键词： 曲线箱梁剪力滞荷载作用位置受力分析　出处：《苏州科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着城市道路的不断扩大,由于城市建设的需要,大量曲线桥迅速兴起。曲线桥在弯扭耦合作用下受力十分复杂,而箱形梁由于其优秀的抗弯和抗扭的特性,在曲线桥的应用中愈加广泛。曲线桥在受力中还存在一个重要的现象,即剪力滞效应,如若在设计中忽视剪力滞效应,将会给结构的稳定带来很大的影响。目前,针对直线箱梁桥剪力滞效应的研究已经较为成熟,而对于曲线箱梁桥的剪力滞效应的探讨还需要继续深入,大部分学者研究曲线箱梁剪力滞时,都是从截面的特性和结构的几何参数的变化入手,但是由于曲桥存在弯扭耦合的受力特征,荷载作用的形式和位置对其剪力滞效应也有很大的影响。本文用能量变分法推导了曲线箱梁考虑了约束扭转和自由扭转应变能、约束扭转翘曲应变能的剪力滞系数表达式,并以苏州市中环快速路高新区段的一座三跨曲线连续钢箱梁桥为实例,应用有限元分析软件ANSYS建立有限元模型,针对桥梁模型在受不同纵向位置的对称荷载和不同的横向位置的偏心荷载作用的情况下,分析截面剪力滞系数的分布及变化,并得出截面的剪力、弯矩及扭矩值,从而得出曲桥所受的弯、剪、扭作用对其剪力滞效应的影响,最后将直线箱梁剪力滞效应与本文曲线箱梁剪力滞效应进行对比。由分析结果可以看出,不同荷载位置作用下,曲线箱梁剪力滞系数的横向分布波动较大,不断经历着正负剪力滞的切换;荷载的横向变位下,剪力滞效应总是在荷载作用点附近波动较大;荷载的纵向变位只对荷载所作用的截面的剪力滞效应影响较大;弯、剪、扭作用均对剪力滞效应都有较大的影响,其中偏载加载时扭矩变化相较剪力和弯矩更明显,对剪力滞效应的影响不容小视;与直线箱梁相比,曲线箱梁的横向分布规律不具有直线箱梁的对称性和偏载加载时的递减性。
[Abstract]:With the continuous expansion of urban roads, due to the needs of urban construction, a large number of curved bridges rise rapidly. Curved bridges are subjected to complex forces under the action of bending and torsion coupling, while box beams have excellent bending and torsional characteristics. In the application of curved bridge, there is still an important phenomenon, that is, shear lag effect, if the shear lag effect is ignored in the design of curved bridge. At present, the research on the shear lag effect of the straight box girder bridge has been more mature, but the research on the shear lag effect of the curved box girder bridge needs to be further studied. Most scholars study the shear lag of curved box girder from the characteristics of section and the change of geometric parameters of the structure, but due to the bending and torsional coupling of the curved bridge force characteristics. The form and position of load also have great influence on the shear lag effect. In this paper, the constrained torsion and free torsional strain energy of curved box girder are derived by energy variation method. The expression of shear lag coefficient of constrained torsional warpage strain energy is given, and a three-span continuous steel box girder bridge in the section of Suzhou Central Expressway High-tech Zone is taken as an example. The finite element analysis software ANSYS is used to establish the finite element model. The bridge model is subjected to symmetrical loads in different longitudinal positions and eccentric loads in different transverse positions. The distribution and variation of shear lag coefficient of section are analyzed, and the shear force, moment and torque of section are obtained, and the influence of bending, shear and torsion on shear lag effect of curved bridge is obtained. Finally, the shear lag effect of linear box girder is compared with the shear lag effect of curved box girder in this paper. From the analysis results, it can be seen that the transverse distribution of shear lag coefficient of curved box girder fluctuates greatly under different load positions. Constantly experiencing positive and negative shear lag switching; Under the lateral displacement of the load, the shear lag effect always fluctuates greatly near the load action point. The longitudinal displacement of load only has a great effect on the shear lag effect of the section acted by the load. Bending, shear and torsion all have great influence on shear lag effect. The change of torque is more obvious than that of shear force and bending moment under eccentric loading, and the influence on shear lag effect should not be ignored. Compared with the linear box girder, the transverse distribution of the curved box girder does not have the symmetry of the straight box girder and the decreasing of the partial load.
【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441

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