Structural Design from Reclaimed Material Sauvabelin – The Never-Ending Story

This thesis is developed as part of the final year project that must be completed to obtain the MCs degree in Civil Engineering at EPFL. It follows up the pre-study project carried out during the last semester of the course. The environmental crisis that our society is currently facing is no longer a surprise to anyone. While a shift of mindsets can slowly be observed in many fields of activity, the construction sector remains one of the most energy-intensive sectors that consumes enormous quantities of materials resulting in an important amount of waste and relative emissions. The shift of paradigm from an oil-based economy toward a material economy will progressively enforce the daily use of reclaimed materials within our infrastructures. Designing from reclaimed materials, however, reverse the usual design process and not only requires new tools but also requires new regulations. The project is developed around the concept of reuse and aims to assess the potential to reuse in the timber construction domain. The first part of this report is dedicated to the assessment of the potential and limitations of such strategy while the second part is centred around the development of a fictitious case study. The case study aims to propose a feasible design for the new lookout tower of Sauvabelin considering that its load bearing structure could be built from reclaimed elements of the existing tower. The project is intended to be used as a banner to reuse by demonstrating the early-stage feasibility and benefit of implementing a reuse strategy. It is further hoped that the project can be used as a discussion tool to initiate reflection on the future of the Sauvabelin Tower. The project therefore brings together structural, architectural, and environmental considerations that need to be balanced out to obtain a sustainable design. The project involves the use of the decision support tool Phoenix 3D, developed at the Structural Xploration Lab in Fribourg, which provides the assignment of an available stock and new elements to member positions of truss structures. A parametric design of the load bearing system is implemented in the Rhinoceros 3D – Grasshopper environment to be able to perform some optimization regarding its environmental impact and other quantities assessed through Phoenix 3D. The project proves the feasibility of the pursued strategy and show that a load bearing structure with similar height can be constructed only from the reclaimed elements of the current Sauvabelin Tower. It was, furthermore, assessed that the environmental impact of the load bearing structure can theoretically be reduced of about 45% in implementing a reuse strategy. The retained design and final look of the tower are finally presented in the last part of this report.