为了解新型Kiewitt型索穹顶结构的受力性能,采用节点平衡理论和平衡矩阵理论对该结构的自应力模态进行了详细分析,并对这类具有多个整体自应力模态的索穹顶结构采用非线性规划、以初应变能最小为优化目标进行了预应力优化.研究表明,考虑结构对称性后体系超静定次数等于基于平衡矩阵理论运用奇异值分解法求得的整体白应力模态数,且其整体模态数随环索数的增加而呈规律性增加,预应力优化后的合理初始预应力分布在一定的荷载工况作用下由于部分索临近松弛而达到极限状态.
In order to investigate the structural behavior of a new type of cable domes-Kiewitt domes, the selfstress modes of Kiewitt domes were analyzed by equilibrium matrix theory and node equilibrium theory respectively. Taking the minimum initial-strain energy of the structure as the objective function, optimal prestress design of the structures with multi-overall selfstress modes was carried out by nonlinear programming algorithm. Numerical results show that the number of the overall selfstress modes is equal to the re- dundant order of the dome after considering the symmetry of the structure, and it increases regularly with increase of the hoop number. The optimal initial prestress distribution reaches the limiting state by some cables slack under certain load condition.