Grade: summa cum laude
On 16 July 2026, Benedikt Strahm defended his doctoral research titled "Design for the Reuse of Concrete Slabs Through Optimized Segmentation and Reversible Jointing" with distinction in front of the doctoral committee. The doctoral committee consisted of Prof. Dr.-Ing. Ullrich Martin (IEV) as chair, Prof. Dr.-Ing. M.Arch. Lucio Blandini (ILEK) as supervisor and first examiner, and Prof. Dr. Corentin Fivet (SXL, EPFL Lausanne) as second examiner
Congratulations to Benedikt Strahm on his outstanding achievement
The reuse of concrete components can significantly reduce greenhouse gas emissions, waste volume, and natural resource consumption in concrete construction. In particular, the reuse of concrete slabs, which constitute the largest mass share of conventional concrete structures, has attracted considerable interest.
Currently, the design process for newly constructed concrete structures does not prioritize reuse. Most concrete structures are monolithic and cast in-situ, hindering the separation and recovery of individual components. Moreover, neglecting reuse in the initial design intent results in structures designed for a single specific scenario. This specificity limits the flexibility and potential applications of reclaimed components after deconstruction. This research addresses these key technical barriers for future reuse by investigating segmented, reversible concrete slabs.
In order to integrate future reuse scenarios into the initial design process, the thesis proposed a design method based on a multi-objective optimization algorithm. The design method facilitates the decomposition of concrete slabs into segments for application within a prescribed range of architectural functions and structural configurations. The potential of the design method was demonstrated using a case study, revealing that the intentional design for reuse facilitates the generation of a stock of segments for application in a variety of scenarios.
To join individual segments to a continuous structure, a demountable prestressed connection was proposed. The bending and shear load-bearing behavior, the influence of the level of prestress, and the disassembly and reassembly of concrete beam segments employing the connection were investigated. It has been demonstrated that the proposed connection facilitates joining the segments to a continuous structure that exhibits a load-bearing behavior comparable to that of a monolithic structure, while also allowing for the assembly, disassembly, and subsequent reassembly of individual segments.
Through the integration of design for reuse into the design process and the implementation of intentional design for dis- and reassembly, the research proposed a novel approach for designing segmented concrete slabs. The segmented slabs can be deconstructed, individual segments can be reclaimed, and subsequently be reused elsewhere, enabling substantial reductions in the environmental impact of concrete structures.
