What was truly innovative about Maillart's designs using reinforced concrete?

This paper attempts to reveal the specific nature of the work of Robert Maillart [1872-1940], after carefully reviewing the historical context of concrete design. Maillart's favourite material was reinforced concrete, and he devised forms that synthesised all the characteristics of a relevant structure. He succeeded by establishing a clear status for each material used – concrete and reinforcement steel – which allowed him to define the geometry of his structures correctly. This is demonstrated here by an analysis of the design drawings for the Salginatobel Bridge and the Chiasso Shed. These examples offer clarification of the use he made of calculation and graphic statics for design purposes. We conclude with the specificity of his approach as a singular vision of how (reinforced) concrete can be used within a structural scheme, which in turn allows an original, expressive structure to be produced of great relevance and reliability.