An ultimate limit state theory for stressed skin design

摘要

The stressed skin (diaphragm) design of steel framed structures is now well established. It is embraced by many national and international design standards and widely used in practice. The design expressions in current use were established many years ago on the basis of approximate elastic distributions of internal force. Both the seam fasteners between adjacent panels of steel sheeting or decking and the fasteners which connect these elements to the supporting primary structure play a crucial role in stressed skin design. Although other failure modes are considered, the critical mode of failure is nearly always a fastener mode. These fasteners exhibit non-linear behaviour from an early stage of loading and it is a requirement that they fail in a ductile manner. It follows that strength design on the basis of elastic distributions of force is not rational and is unlikely to be economic. This paper shows that the plastic distributions of fastener force at failure for a wide variety of practical situations are statically determinate and can be readily predicted by manual methods.