The continuous strength method for steel and composite design

Steel and steel–concrete composite construction is employed in a substantial proportion of low-rise and multi-storey buildings. Design codes for these forms of structure have evolved over many years, but are currently essentially founded upon the assumption of elastic-plastic or rigid-plastic material behaviour and largely disregard the beneficial influence of strain hardening. This simplificaton can result in overly conservative predictions of capacity, particularly in the case of stocky, bare steel cross-sections and composite beams under sagging bending moment. The continuous strength method is an alternative deformation-based design approach that allows for strain hardening, provides more accurate predictions of member capacities and, thus, enables more efficient structural solutions to be achieved. In this paper, the development and application of the continuous strength method to steel structures is explained and extension of the method to steel–concrete composite design is outlined.