The Stability Study of an Innovative Steel Dome

Global stability of an innovative dome comprising of double-layer space frame sections together with curved flexural members has been studied. The dome had both an outer flat and an inner spherical double-layer grid space frames and formed the roof over a joint ballroom and meeting space of 3,100 square metres. The relatively wide spans between the outer and the inner space structures were covered using thirty six curved flexural pipe members laid on a synclastic surface. These members were employed for architectural purposes to provide a clear glazed area for the roof. Introducing relatively large span flexural members joining the two lattice space frames together complicated the overall structural response of the dome. It also made the dome susceptible to different premature instability modes. The non-linear FE program ABAQUS [1] was utilised to study the global stability of the dome and to investigate fully both its pre and post failure behaviour. Different member configurations were considered for the dome and their effects on the behaviour; stability, snap through buckling and the collapse load of the structure were investigated. In the dome responses, several failure modes such as overall torsional buckling, in-plane ring buckling and symmetrical and non-symmetrical vertical snap through were identified. It was noted that the presence of restraints placed between the flexural members could prevent the occurrence of premature torsional and vertical snap through buckling in the dome. The global behaviour of the dome appeared to be very sensitive to both the type and configuration of the restraints applied along the flexural members. The dome was also found to be remarkably sensitive to non-symmetric loads.