提出一种新型的环箍穹顶全张力自平衡索杆结构,该体系以环形张拉整体为周边环梁,中部支承Lew型索穹顶结构。由于该环箍穹顶结构冗余度较低,该文研究了局部索失效情况下的结构抗倒塌性能。考察了环形张拉整体中局部拉索破断后索穹顶环向约束刚度的降低程度,以及整体结构力学性能的影响。基于显式动力积分法,运用变换荷载路径法,通过移除失效拉索单元,分析模拟了环形张拉整体不同部位的拉索断裂后剩余结构的响应,包括节点位移、索杆内力等指标。根据响应值将断索分成四种类型,并对四种类型的索破断后结构是否产生连续倒塌进行了探索。分析结果表明,提出的环箍-穹顶索杆结构具有较好的抗连续倒塌性能,相关结论将为此类结构的工程应用及安全评估提供借鉴。
A novel self-equilibrium cable-strut tensile strucuture called torus-dome was proposed. The system consists of a surrounding tensegrity torus and a central Levy type cable dome. Because of the low redundancy, the anti-collapse performance of torus-dome structures under local cable rupture is studied. Considering the rupture of cables in the tensegrity torus, the constraint reduction of tensegrity around the cable dome is systematically discussed. The impacts on the overall structural stiffness and the internal force redistribution of cables and struts are also discussed. Based on the explicit dynamic integration method, the behavior of the remaining structure was investigated by ANSYS/LS-DYNA software package. Alternative load path method was applied to simulate the structural responses, including the nodal displacements and the internal forces of cables and struts. The invalid cables are divided into four groups and the anti-collapse capacity of the remaining structure is evaluated. The results indicate that the structure has good performance to resist progressive collapse. The conclusions will provide a reference of engineering application and safety assessment for such structures.