Public thesis defense Martin STEINMETZ - LAB
sst |
Engineering Reciprocal Structures : Applications to Floors and Domes.
Friday July 3rd, 2026 - 4pm - Auditorium BARB91 - Place Sainte-Barbe, 1 - 1348 Louvain-la-Neuve
Reciprocal structures (RS) are often likened to a game of pick-up sticks because of their lack of a clear hierarchy. An RS consists of one or more modules, each comprising at least three beams, enabling an infinite number of associations and, thus, geometric freedom. It combines architectural appeal with the ability to span long distances using relatively short structural elements, which is particularly relevant when built with logs, as they are naturally limited in length. However, wider adoption remains limited due to uncertainties about their structural efficiency, geometric stability, and the numerical predictability of the connections. The objective of this thesis is to establish a reliable design framework for reciprocal structures by addressing these barriers.
The structural efficiency of RS is demonstrated by comparing RS log floors with conventional timber floor patterns. The research shows that a reciprocal pattern yields a material-efficient, thin floor solution for square layouts, sometimes outperforming conventional patterns.
Geometric stability is then examined using existing connection systems and stability assessment methods. A universal approach is identified to detect unstable configurations at the early design stage, thereby enabling consistent preliminary design rules.
Finally, modelling reliability is addressed through a novel spherical hinge connection for spatial RS. Experimental tests on large-scale prototypes show strong agreement with numerical predictions, confirming that accurate modelling is possible when the connection behaviour is properly represented.
Jury members
Prof. Luca Sgambi (UCLouvain), Supervisor
Prof. Pierre Latteur (UCLouvain), Supervisor
Prof. Denis Zastavni (UCLouvain), Chairperson
Prof. Joao Almeida (UCLouvain), Secretary
Prof. Elsa Garavaglia (Politecnico di Milano, Italy)
Prof. Cyril Douthe (Ecole nationale des ponts et chaussées, France)