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提出一种新的预应力空间结构体系——弦支筒壳结构体系,它是基于弦支梁(或弦支桁架)和柱面网壳的复合空间结构,并给出其预应力设计方法。研究了弦支筒壳结构的稳定特性,并重点讨论了长跨比、矢跨比、垂跨比、撑杆数以及初始缺陷和半跨荷载等几个重要参数对弦支筒壳结构稳定性能的影响。研究表明,弦支筒壳的屈曲特征值和非线性屈曲临界荷载值均比单层筒壳大幅度提高;长跨比对弦支筒壳结构稳定性影响较小;在一定范围内增大矢跨比和垂跨比均可改善弦支筒壳的稳定性,但同时会对局部撑杆的稳定性产生不利影响;撑杆较少时,增加撑杆数会在一定程度上改善结构的稳定性,但随着撑杆数的增加,这种改善作用不再明显;初始缺陷对结构的稳定性有不利影响,增大初始缺陷会加剧这种不利影响,尤其当初始缺陷超过跨度的1/300时,这种不利影响会充分展现,不容忽视;半跨荷载对结构的稳定性不利,但这种不利影响较弱。
A new prestressed spatial structure system, chord support shell and shell structure system, is proposed, which is based on the composite space structure of chord beam (or chord support truss) and cylindrical reticulated shell, and gives the prestressing design method. The stability characteristics of chord support shell structure are studied. The stability of chord support shell structure with several important parameters such as long-span ratio, sag-to-span ratio, vertical / span ratio, strut number, initial defect and semi- Impact. The results show that both the buckling characteristic value and the nonlinear buckling critical load value of the chord support shell are significantly higher than that of the monolayer shell. The long-span ratio has less influence on the stability of the chord support shell structure. In a certain range, Both the ratio and the vertical-span ratio can improve the stability of the chord support shell, but at the same time it will adversely affect the stability of the local support bar. When the support bar is small, increasing the support bar will improve the stability of the structure to a certain extent , But with the increase in the number of struts, the improvement effect is no longer obvious; the initial defects have an adverse effect on the stability of the structure. Increasing the initial defects exacerbates this adverse effect, especially when the initial defect exceeds 1/300 of the span , This adverse effect will be fully demonstrated and can not be ignored; half-load is not conducive to structural stability, but this adverse effect is weaker.