Deformation based design of steel and composite structural elements

Steel and composite structures are traditionally designed through strength based calculations. An alternative approach is to consider deformation capacity. Deformation based design enables a more accurate allowance to be made for the spread of plasticity and allows strain hardening to be considered in a systematic manner. Importantly, the level of deformation required by the structure at ultimate limit state to reach the required design capacity can also be assessed. In composite construction, deformation based design enables a more rigorous assessment to be made of the development of strength in the structural system taking due account of the compatibility between the constituent materials. In this paper, recent developments to the deformation based continuous strength method for steel and composite design are described. Comparisons of capacities obtained from experiments and numerical simulations with those predicted using the continuous strength method are presented and discussed. Recommendations for future work on this topic are also set out.