钻石型轮辐结构构型与受力性能研究

Configuration and Mechanical Behavior of Diamond-Shaped Spoke Structure

本文给出了钻石型轮辐结构的构型规则,并对其预应力态和张拉成形方法进行了探讨.通过1∶15缩尺模型试验,考察钻石型轮辐结构施工张拉成型的可行性,检验屋盖结构的受力性能,验证数值模拟方法与试验结果的一致性.研究钻石型轮辐结构成形态的动力特性以及在活荷载、风荷载和温度作用下的结构变形和构件内力以及断索对结构性能的影响,重点考察中间撑杆高度变化对结构受力性能的影响.缩尺模型试验结果表明,提升下径索所需张拉设备数量较少,施工方便;对于结构的成形态和静力加载工况,实测与数值模拟得到的内环节点标高、索力、结构变形具有较好的一致性.有限元分析结果表明,中间撑杆高度对结构动力特性、构件内力和结构变形的影响较为显著.在结构的成形态,随着中间撑杆高度增大,上径索索力随之加大,内环撑杆由受压变为受拉,中间撑杆的压力迅速增大.大跨度轮辐结构刚度较小,设置中间撑杆后,有利于提高结构的竖向刚度,减小在竖向荷载、特别是在风荷载作用下的变形.此外,半跨荷载作用下结构的竖向变形大于满跨荷载,而正、负温差对结构的内力与变形均不起控制作用.断索引起紧邻径索索力突然增大,次邻径索与环索索力的变化幅度则很小.对于钻石型轮辐结构,中间撑杆高度不宜大于内环撑杆高度.

Herein,the configuration regulations of the diamond-shaped spoke structure are listed,and the prestressed state and tension forming method are discussed.Through a 1∶15 scale model test,the feasibility of tensile forming of the diamond-shaped spoke structure was investigated,the mechanical performance of the roof structure is examined,and the consistency between the numerical simulation method and the test results is verified.The dynamic characteristics of the diamond-shaped spoke structure at the forming state,structural deformation,and internal force of the components under the action of live load,wind load,and temperature difference,as well as the structural performance when the cable is broken,are comprehensively studied.Meanwhile,the influence of the change in the height of the middle strut on the structure’s mechanical performance is primarily investigated.The scale model test results show that less tensioning equipment is required to lift the lower diameter cables,facilitating con·venient construction.For the forming state of the structure under static loading,the inner ring node elevation,cable forces,and structural deformation obtained via measurement and numerical simulation are in good agreement.The finite element analysis results show that the middle strut’s height has a significant effect on the structural dynamic characteristics,the internal force of the member,and the structural deformation.At the forming state of the structures,with the increasing height of the middle strut,the cable force of the diameter cable increases accordingly,the inner ring strut force changes from compression to tension,and the pressure of the middle strut increases rapidly.The stiffness of the large-span spoke cable structure is relatively small.After setting the middle struts,it is conducive to increasing the vertical stiffness of the structure and reducing the deformation under a vertical load,especially under the wind load.In addition,the vertical structural deformation under the half-span live load is greater than that under the full-span live load,and the positive and negative thermal difference is not the key load case for internal forces and deformation of the structure.Cable breaking suddenly increases the cable force of the adjacent diameter cable,while the range of change of the cable force of the secondary adjacent diameter cable and the ring cable is considerably small.For the diamond-shaped spoke structure,the height of the middle strut should not be greater than the height of the inner ring strut.