Probabilistic study of the strength of steel scaffold systems

Steel support scaffold systems are characterised by the large variations of geometric and mechanical parameters, notably joint stiffness, initial geometric imperfections, yield stress and load eccentricity. This paper investigates the effects of these uncertainties on the ultimate strength of multi-storey steel support scaffold frames through a rational statistical framework and a second-order inelastic finite element analysis (advanced analysis). A series of stick type steel scaffold systems with cuplok joints were studied. The statistical data for the basic random variables were acquired through field measurements and laboratory tests. By comparison to load tests, the bias and variability of advanced analysis were estimated. The basic random variables and the model uncertainty are propagated through Monte Carlo simulation to obtain the statistics of system strength. The first-order reliability method is then employed to estimate the reliability of steel scaffold systems designed by advanced analysis.