| Structures such as bottom-founded petroleum exploration and production platforms and ice-breaking vessels are required to resist extreme loads. The loads, primarily due to ice, must be resisted by the hull or exterior wall that is generally made up of a rectangular grid of frames and stiffeners covered by steel plate. The results of the experimental work reported here, supported by the predictions of various analyses, show that thin steel plates with span to thickness ratios of between 65 and 155 are indeed suitable to resist extreme transverse loads without the need for stiffening elements when the resistance provided by membrane behaviour is utilized.;Four tests were carried out on plates with nominal thicknesses between 6 mm and 16 mm and having an aspect ratio, width/length, of 0.34. The plates were loaded transversely by fluid pressure until failure occurred. Deflections and strains at numerous locations were recorded throughout the loading history. The plates all failed at the edge near mid-length where the greatest bending occurred. Although they were considered to have failed prematurely within the heat affected zone of the weld at the plate edges, the plates were loaded for the most part into the inelastic flexural membrane range of behaviour. The failure loads were many times that corresponding to yield-line collapse mechanisms. Three failure mechanisms have been identified. |
