Creep Buckling of Long Columns

In 1969, a study was made of the results of tests on eighty steel-concrete composite beams in which longitudinal shear stress was high, and a new design method for transverse reinforcement in the slab was deduced. This gave a more uniform margin of safety than the method of CP 117 Part 1: 1965, and showed that the amount of reinforcement could be reduced by about 35 per cent.

A description is given of a system of interconnected beams representing a right simply supported multiple web cellular deck with no intermediate diaphragms, followed by an outline of a method of analysing the response of such a system to any externally applied loading. A short computer program using this method of analysis is described. Results produced by this program are compared with experimental results of a model test and show agreement to within a few per cent. Finally it is shown how this theory was applied to the design of the New Cattle Market Bridge now under construction which when completed will carry the new Derby Inner Ring Road over the River Derwent. J.G. Parkhouse

In a previous paper, full-scale and model tests on trough-shaped bunkers, rectangular in plan, were described, and experimental stresses were compared with those from conventional design and from an improved design method {which requires empirical allowances for the contribution of the plating to the longitudinal bending strength). This paper explains two theoretical solutions, the first allowing for shear panel action in the plating and overall hipped-plate behaviour in the bunker, the second utilizing a commercial space frame computer program allowing for in-filled panels. The results obtained compare favourably with those obtained previously by experiment and by the improved design method; either method may now be utilized to check and modify designs for this type of structure. E. Lightfoot and J.K. Withrington