Study on extreme cases for large-span retractable roof structure

The retractable roof structure of the stadium located in Nantong Sport Center under assumed abnormal loads was analyzed to investigate the risk of progressive failure due to accidental events.Three events were considered,including unsymmetrical motion of movable roofs,fracture of one traction cable,as well as slippage and impact of movable roof due to malfunction of electromechanical devices.The effects of geometric large deformation and impact action were taken into account in dynamic analysis.The study shows that main structure can preserve its bearing capacity under unsymmetrical motion of movable roof or fracture of traction cable,but the slippage and impact action of whole movable roof may be detrimental to the structure.Abnormal cases,which are beyond the framework of the current design codes based on structural reliability theory, should be presumed according to structural specialties and then be evaluated for structural safety.