Investigation of geometric imperfections and joint stiffness of support scaffold systems

This paper describes the findings from various site measurements of geometric imperfections of support scaffold systems, also known as falsework in industry. The measurements consist of out-of-straightness of the standards (uprights), out-of-plumb of the frame and loading eccentricity between the timber bearer and the U-head screw jack. The measurements were taken from different support scaffold construction sites before the pouring of concrete, representing actual initial geometric imperfections and loading eccentricity encountered in practice. The paper also reports the results of support scaffold joint tests. The tests were performed on randomly chosen used components to investigate the joint stiffness for rotations about vertical and horizontal axes. Tests were performed for various joint configurations (two-way, three-way, and four-way connections), bending axes, and loading directions. The statistical analysis of the data is presented in the paper for practical application in modelling and probabilistic assessment of support scaffold systems.

Research highlights
► Measurements of geometric imperfections of support scaffold systems are presented.
► A study of the joint stiffness of Cuplok scaffold systems is presented.
► The results are useful for the modelling of support scaffold systems.