高层筒体结构剪力滞后研究

重点讨论了筒体结构剪力滞后效应(SLE:shear lag effect)的产生机理,提出与SLE的力传递说有较大差异的新看法,认为引起筒体结构SLE的原因是沿翼缘方向上的抗侧力刚度不均(称为横向刚度):角柱由于腹板的作用使其抗剪刚度增大,中柱则相对抗剪刚度减小。刚度低的中柱产生较大弯曲变形,使裙梁及楼板也跟着变形,中柱抗弯能力降低,轴力减小,由于腹板的作用而刚度增大的角柱轴力自然会增大。利用大型有限元软件ANSYS对高层筒体结构在水平风荷载作用下进行计算分析,得出:角柱截面变化只是对其本身轴力影响很大,考虑到角柱在筒体结构中的重要性应适当增大其截面面积;去除角柱不但不能降低甚至消除SLE,反而使结构整体性降低。

Shear Lag Effect in Tall Tubular Structures

The causation of the shear lage effect(SLE) in tall tubular structures was investigated.That is the rigidity of lateral load resistance(the transverse rigidity) on the flange way is imbalance,therefore,the shear bearing stiffness of the angle post increases under the effect of the web plate,but that of the neutral post decreases comparatively.The neutral post with low stiffness becomes bended and distorted,causing the deformation of the beam and joist.Its flextural capacity and axial force reduce.Then because the stiffness of the angle post grows under the effect of the web plate,the axial force of it will certainly increase.This is greatly different from the supposition of force transmission.The finite element analysis software(ANSYS) was used to caculate and analyze tall tubular structure affected by horizontal wind load.The results showed that the variational section of the corner column act on its own axial force mainly.Its sectional area should be increased considering its main effect in tubular structure;the SLE of the structures without corner columns can not be weakened or removed,on the contrary,the whole stability will be lowered.