ABSTRACT
The first Code of Practice for concrete wholly based on limit-state principles, caused shock waves to pass through the structural engineering profession. In 1934, the Code of Practice published by the Department of Scientific and Industrial Research permitted axially loaded columns to be designed by summing the individual resistances of the concrete and the reinforcement. The implementation of the limit-state design method presented in CP 110 extends the logic of load-factor design, by permitting the relative uncertainty by which each individual type of load and material strength can be assessed to be considered individually, instead of needing to adopt a single global factor of safety to cater for all the possible uncertainties. The limit-state concept is the rational outcome of a rethinking of the fundamental purpose of structural design, which is to produce structures that are safe, serviceable and economic. Limit-state design is carried out in terms of characteristic loads and characteristic strengths of materials.
