Resumen
This article proposes an progressive-collapse mechanism for suspended-dome structures subjected to cable rupture, based on experimental and finite element results. The anti-collapse mechanism can be succinctly described as a node-buckling mechanism: the potential for node buckling in a local arch-like spatial grid centered on unsupported node directly determines whether progressive collapse will occur in the overall structure. Subsequently, based on this anti-collapse mechanism, a node-buckling model is further proposed, and the factors affecting the anti-collapse bearing capacity of suspended domes are quantitatively expressed through the construction of a resistance index, which can be used to judge the sensitivity of hoop cables. Further, using Ribbed and Lamella suspended domes as examples, extensive calculations demonstrate the applicability and accuracy of the node-buckling model and resistance index to other types of suspended domes. Finally, the resistance index is used to analyze two important but easily overlooked factors that affect the anti-collapse bearing capacity of suspended domes. Initial geometric imperfections result in a rise?span ratio too small for the local arch-like spatial grid, while the lack of lateral stiffness at the supports will weaken the axial stiffness of the outermost radial or diagonal members. Both of these factors significantly reduce the stability of the local arch-like spatial grid, making it more likely to trigger progressive collapse in suspended-dome structures.