Experimental study on the construction shape-forming process and static behaviour of a double strut cable dome

Abstract

A double strut cable dome structural system was presented to improve the mechanical behaviour of a cable dome. This structure has good stability and is convenient to construct. To investigate its construction method and static performance, a structural model with a 6-m diameter was designed. From the nodal equilibrium equation, the calculation formulas for the prestress distribution with self-weight considered were deduced. Two types of construction methods, namely, assembling at high altitude and integral lifting, were adopted in the shape-forming process of the double strut cable dome, monitoring the internal force of the cable-strut components and the structural deformation. According to loading tests under full-span load and half-span load, the static behaviour of the structure was obtained and compared with the results from finite element analysis. Using the formulas deduced in this paper, the actual initial prestress considering self-weight for a double strut cable dome can be obtained accurately. This structure was suitable for tensioning the outer diagonal cables to apply prestress. Combined with the construction method for integral lifting, the difficulty and workload of the construction process can clearly be reduced, making the structure favourable for engineering application. Under an external load, the internal force of the ridge cables and inner diagonal cables decreases and the internal force of the other components increases. The results of the model tests were in good agreement with those of the finite element analysis.

中文概要

目的

提出一种稳定性好、便于张拉施工的双撑杆索穹 顶结构,以解决该结构的找力分析问题,并考察 其施工方法和静力性能,为工程实践提供参考依 据。

方法

1. 通过节点平衡方程,推导出考虑结构自重时的 双撑杆索穹顶结构的预应力分布计算公式;2. 通 过模型试验,比较采用空中组装和整体提升两种 施工方法时,结构的内力和位形变化;3. 进行满跨荷载和半跨荷载的加载测试,并与有限元分 析结果进行了对比。

结论

1. 本文所得公式可以准确得到双撑杆索穹顶结构 考虑自重后的实际预应力分布。2. 该结构适合通 过张拉外斜索施加预应力;结合整体提升的施工 方法,可以显著降低施工难度,使其更适用于实 际工程。3. 在外荷载作用下,双撑杆索穹顶结构 中脊索和内斜索的内力减小,其他斜索和环索的 内力增大。