Visionary realism. Designing Sergio Musmeci’s bridge over the Niger river today

The structures created by Sergio Musmeci (1926 - 1981) feature an “expressive language” combined with mathematically proven static efficiency. These “organic structures” result from a form-finding process in which the quantity of material in the minimal surface form is reduced to counteract the potential energy of an external force system […] Rather than being driven by whim or intuition, the search for the structural form is the outcome of a process concerned with the optimal arrangement of matter in space to accomplish a specific structural task with the least amount of resources […] (Musmeci 1971). The concrete structure of the Niger Bridge, a double curved surface discretised into linear rods, is the focus of this article. Despite the use of prefabricated concrete components, the structural design, complexity of construction management and high labour costs limited its feasibility, even if it makes sense in terms of the spatial organisation of materials. However, recent digital developments in technical tools have opened up new possibilities for greater control over both design and construction. This article examines the design methodology of the Ajaokuta Bridge and, based on these considerations, analyses its modelling using state-of-the-art computational design techniques. In particular, spatial exploration based on a system of prismatic and antiprismatic elements (nodes) is discussed as a recurring key role. Furthermore, the research aims to apply Musmeci's form-finding methodology through an integrated digital workflow, aimed at construction strategies employing on-site 3D printing. To investigate the morphogenesis of three-dimensional structural creation in detail, graphical algorithms have been developed.