变截面混凝土薄壁箱梁剪力滞效应研究

【作者】 万颖君；

【导师】 杜时贵； 彭卫；

【作者基本信息】 浙江工业大学 ， 固体力学， 2003， 硕士

【摘要】 本文以工程中常用的变截面箱梁桥为研究对象，分别采用平面有限元和空间有限元两种方法计算了各种荷载组合下控制截面的剪力滞系数和有效宽度比，对该类箱梁的剪力滞效应进行了分析。并用工程实桥的空间有限元分析结果比较了各国规范(中国、德国、美国)中有效宽度规定的精度。文中还分析了宽跨比、梁高比、荷载类型、截面位置等参数对变截面箱梁剪力滞效应的影响。 研究结果表明： (1)空间有限元模型能够较准确地反映出箱形梁桥实际结构截面的受力情况，箱形梁的剪力滞效应不容忽视； (2)用平面杆系分析方法进行设计计算时，对于剪力滞效应的影响，可按德国规范(DIN1075)的规定以有效宽度的形式计入，而我国现行规范(JTJ023-85)中的有关规定过于保守，不经济； (3)剪力滞效应严重地受到宽跨比、梁高比、荷载类型及截面位置的影响，而横截面悬臂长度、腹板倾斜程度等截面几何参数对剪力滞效应的影响不大； (4)对于翼缘净悬出宽度与跨径之比小于0.05的连续箱梁桥，剪力滞效应对结构的影响并不明显，设计时可不考虑翼板有效宽度的折减； (5)集中力作用处剪力滞效应与其它截面相比明显增大，我国现行桥规(JTJ023-85)中关于有效宽度取全桥等宽的说法需要进一步研究。更多还原

【Abstract】 Based on theoretical analysis and finite element method, the paper investigates the shear lag effect of box girder bridges with variable cross sections. It concentrated on calculating the shear lag coefficient and effective flange width coefficient in different combinations of loading. Two examples of prestressed concrete continuous box girder bridges with variable cross sections are involved. The result of example 2 is presented to compare the precision of effective flange width in the standards of China. Germany and US. Moreover, some sensitive factors such as width-length ratio, girder height ratio, loading arrangement and the section’s location are analyzed.The conclusions are as follows:The spatial FEM can relatively accurately reflect the stress of the practical structure. The shear lag effect of box girder bridges can’t be neglected. With regard to effective flange width, the standard of Germany (DIN 1075) is more accurate, however National Standard (JTJ023-85) is apt to be exaggerated. The shear lag effect is seriously effected by width-length ratio, girder height ratio, loading arrangement and the section’s location. The shear lag effect of the continuous box girder bridges with width-length ratio less than 0.05 is not obvious, whose effective flange width can be ignored. The shear lag effect of the section under concentrated load is more remarkable than that of other sections. National Standard (JTJ023-85) is worth discussing further.更多还原