Abstract
The object of this investigation is to review the rational and safe use of plain, reinforced and prestressed concrete as structural media. Developments in technology seem to precede science, which in turn has to explain these achievements systematically and rigorously. This order of events, in the case of concrete technology, stretches back thousands of years, yet only centuries to the beginnings of conscious scientific postulations. Therefore, it should not be surprising that even today many inconsistencies, or indeed contradictions, persist to cloud fundamental issues with regard to safety. Following a systematic historical review, and an explanation of the present State of the Art, the Author presents simple design recommendations based on a full recognition of the fundamental role of the tensile strength of concrete, bearing in mind its inherent elasto-plastic properties. These recommendations acknowledge the rationality of the current ultimate limit state concepts with respect to flexure and postulate straightforward yet safe proposals for resolving the continuing confusion with regard to combined shear and flexure.