凯威特型索穹顶结构多种张拉成形方案模型试验研究

张拉成形技术属于索穹顶结构的关键技术。为分析比较各种张拉成形方案的施工可行性和方便性,同时深入理解预应力生成机理,对一凯威特型索穹顶结构模型进行了逐步张拉外圈斜索成形、一次性张拉外圈斜索成形及由外及里逐步调节压杆到原长成形等三种成形方案的张拉成形试验,跟踪了张拉成形全过程。试验研究表明：三种张拉成形方案都是可行有效的,其中一次性张拉外圈斜索成形方案施工较为方便;逐步调节压杆长度到原长成形方案精度相对较高;控制构件原长的张拉成形控制技术不仅适用于单整体自应力模态体系,也适用于多整体自应力模态体系;体系预应力伴随着构件的逐步张拉到位而逐步生成。

Experimental research on construction of a Kiewitt dome model pre-tensioned by different schemes

Construction technique is a key issue for cable domes. In order to compare the feasibility and convenience of every construction scheme and comprehensively understand the mechanism of the pre-stress process, a Kiewitt dome model is designed and three construction schemes, including pre-tensioning the outer diagonal cables step by step, pre-tensioning the outer diagonal cables only once and adjusting the length of struts from outer to inner hoop, are investigated and every whole construction process is tracked. The consistency of the model responses at every construction stage with the computation results indicate the above three construction schemes are all feasible and effective for construction, and the scheme of pre-tensioning the outer diagonal cables only once is more convenient and the scheme of adjusting the length of struts from outer to inner hoop has higher precision. The results also demonstrate the technique by controlling the original length is suitable not only for the cable domes with single overall self-stress mode but also for the cable domes with multi overall self-stress modes, and the pre-stress of the system is gradually produced along with the pre-tension of the members.