Results are described of a theoretical and experimental investigation of the effects of collision damage in the form of elasto-plastic lateral bending and local indentations, on the stiffness and strength of tubular steel bracing members. Full-scale tests have been carried out on two pairs of nominally identical braces obtained from the BP West Sole Platform, recently removed from the North Sea following completion of service. One tube from each pair was tested to collapsl under compres sive load in an initially undamaged condition while the second was tested to collaple following application of simulated collis:·.on dama,.:,e, thus providing a direct indication of damage effects. Results were found to correlate satisfactorily with theoretical analysis and with four tests on small-scale tUbes representing as closely as possible the fullscale experiments. The relationship between collision loads and damage deformations was examined.

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Methods for measuring residual stresses and distortions in welded structures are described and initial results are given of a suwey being carried out during manufacture of warship hull sections. The stresses are determined by measuring the elastic strain induced in the plate and stiffeners due to contraction of the stiffener welds, and profiles of the stiffener and plating after welding have been obtained. The survey is intended to provide information for use in future design calculations of the buckling strength of ship hulls.