索端弹簧刚度对索网受力性能的影响分析

Effect of Spring Stiffness at One End of Cable on the Force Behavior of Cable Net

由于关于索网幕墙端部加弹簧装置的研究很少,因此,对如何选取索端弹簧刚度以及弹簧在索受力过程中有何种作用是索网幕墙设计工作十分关注的问题。为此,基于北京奥体南区3号地项目前期索网计算模型,在保证外荷载和各索预应力或索网最大挠度不变的条件下,分析了弹簧刚度对索网受力性能的影响。结果表明:在外荷载相同时,弹簧刚度越小,竖索的轴力和竖向支座反力越小,对满足竖索及与竖索相连主体结构的承载力要求越有利,但同时会引起横索轴力和竖索最大挠度或竖索初始预应力的增大;弹簧刚度越小,竖索的内力越不均匀,并且这种不均匀程度主要与竖索承受的重力荷载有关,而与初始预应力和挠度变化无关;弹簧刚度越小,弹簧参与整体受力的程度越大,但不能以弹簧与索的线刚度比值1作为划分弹簧参与整体受力程度的依据;满足设计要求的弹簧刚度不唯一。

Very few research is done on curtain wall supported by cable net with spring mechanism, so how to select spring stiffness and what role the spring does in the process of bearing becomes the focus of curtain wall designer. Based on the previous calculation model of No. 3 building in the southern district of Beijing Olympic, the effect of spring stiffness on the force behavior of cable net is analyzed with the condition that the load and pre-stress or maximum deformation is the same. It shows that： the smaller the spring stiffness is, the smaller the vertical axial force and its support reaction are, which will be benefit for satisfying the bearing capacity of the vertical cable itself and the main structure connected with it, but it will also increase the axial force of horizontal cable and the maximum deformation or the pre-stress of vertical cable; the smaller the spring stiffness is, the more uneven the internal force of vertical cable is, of which the even degree is mainly related with gravity load that the vertical cable bears and has no relationship with the pre-stress and the deformation; the smaller the spring stiffness is, the greater degree that the spring takes part in the whole cable net is, but the degree can＇ t be divided by the ratio value 1 gotten by the spring stiffness divided by the linear stiffness of cable ; the design requirement can be met by several kinds of spring stiffness.