Stabilitätsbemessung dünnwandiger, druck- und biegetorsions-beanspruchter Elemente unter Berücksichtigung örtlicher Instabilitäten

The design of thin-walled structural components according to the modern standards is based essentially on formulas that either represent the theory very simplified or have a clearly empirical basis. The reason for this is the absence of practicable numerical analysis methods until recently. The lack of tools which are reliable and able to be used in practice for the deisgn of thin-walled asymmetrical members in accordance with the standards is particulary obvious. Torsion moments caused by loading eccentric to the shear centre (inherent torsion moments), lack of symmetry in the cross section and different forms of elastic restraints can not be modelled in a simple practicable way. The use of analysis systems based on an 2 nd order flexural torsional theory could provide valuable extended design opportunities in the future. Local instabilities may be considered within this method using effective widths and reduced cross section capacities. The consideration of small elastic spring stiffnesses caused by action of connected structural members such as roof cladding systems leads to a more economic design. The influence of geometrical imperfections should be estimated. In addition numerical calculations, using shell elements, were carried out to verify the concept.