大跨度纺锤形气撑式张弦梁找形分析

气撑式张弦结构是一种利用预应力建立初始刚度的新型结构体系,为研究结构在初始预应力作用下位形变化对其力学性能的影响,采用改进的逆迭代法对60 m跨度纺锤形气撑式张弦梁进行找形分析,研究了找形对结构初始态下内力分布和荷载态下极限承载力的影响,对比了该结构与桁架、传统张弦梁的力学性能和经济性.结果表明:找形后初始态上弦位形误差只有矢高的0.67%;经找形结构初始态下内力分布较未经找形结构发生明显改变,且荷载态下竖向承载力降低22.24%;气撑式张弦结构刚度较等跨度桁架和传统张弦梁要低,但用钢量要少34.80%.找形分析可有效控制大跨度气撑式张弦梁初始态位形误差,但对其力学性能影响较大.

Form finding analysis of large-span spindle Tensairity beam

Tensairity is a new kind of hybrid structure system using pre-stress to build the initial stiffness. To study the mechanical performance effected by structural deformation under the initial pre-stress, the form finding analysis of a 60 m span spindle Tensairity was conducted by the improved inverse iteration. The effects of form finding were discussed, and the mechanical performance and economics were compared with truss and beam string structure. The results show that: under the initial state the deformation tolerance could be reduced to 0.67% and the inner force distribution differs obviously, and under the load state the vertical bearing capacity decreases 22.24%. Compared with truss and beam string structure, the stiffness is weaker while the steel consumption is 34.80% less. Form finding analysis could effectively control the deformation tolerance under the initial state though having great impact on the mechanical performance, which holds remarkable economic efficiency and application properties.