The Strength of Scaffold Towers under Vertical Loading

Several single-storey model scaffold towers were loaded to collapse to indicate the effects of different bracing arrangements and couplers. They were also analysed for
overall elastic instability by means of a modified finite displacements program, which added deflexions to co-ordinates as the loading was increased. No allowances were made for elastic connections or for eccentricity of bracing. The finite displacements method was also used to analyse two three-storey Millshore towers which had previously been tested. Several conclusions are drawn about the effects of different bracings and couplers. The overall elastic instability predictions were found to be within 20 per cent for the model tubular scaffolds and close enough for design, i.e. within about 10 per cent, for the full-scale towers. Failure by lateral-torsional buckling of the second Millshore tower which incorporated open section puncheons was correctly predicted. A design recommendation is made for the effective lengths of scaffold columns.

H.S. Harung, E. Lightfoot and D.M. Duggan