Simulation on Load-Carrying Capacity of Scaffold Structures with Imperfections

The coupler-type formwork support system is extensively adopted in China’s construction industry owing to its structural efficiency and cost-effectiveness. However, quantitative design methods for such systems remain challenging due to computational inaccuracies in characterizing semi-rigid coupler joints and imperfections in practical implementations. This study investigates the load-carrying capacity of scaffold structures with inherent defects through advanced numerical simulations. A hybrid FE modelling approach was developed, integrating 3D shell elements for critical coupler regions and beam elements for structural members. The model incorporated semi-rigid joint behaviour for right-angle couplers, with experimental validation confirming its accuracy. Parametric analyses evaluated three key factors, i.e. steel grade, coupler casting material properties, and steel tube wall thickness. Results demonstrate that steel strength and tube thickness significantly enhance structural performance, Q450 steel increased ultimate load capacity by 34.35% versus Q235, while 3.6 mm wall thickness improved capacity by 23.78% compared to 3.0 mm. Crucially, coupler material properties exhibited negligible impact on system-level behaviour.