Design concept for high strength composite members subjected to exceptional loads

Recent developments of the global political situation have led to new challenges for the design of buildings for exceptional loads. The design of buildings subjected to impact and blast loads is normally related to heavy concrete structures. Nevertheless, for general buildings two different engineering concepts are already used: the Key element method and the Alternate load path method. For ductile steel- composite structures, resisting dynamic loads more effectively through plastic defor- mations, a novel method based on residual strength of damaged key elements is intro- duced. Those key elements are designed to resist the dynamic short term actions utiliz- ing plastic deformations. In a second step the global structural stability is checked considering the residual strength of the deformed key element. Partial load redistribu- tion may be considered. The Residual strength method guides a way towards a more realistic and hence economic design.