Corentin Fivet

École Polytechnique Fédérale de Lausanne | EPFL · Institute of Architecture

Extracting pieces of concrete from obsolete buildings and reusing them, as is, in new assemblies is today rarely considered a strategy for improving the sustainability of the construction sector. By delaying the crushing of concrete into aggregates and avoiding the need for fresh cement in new buildings, the circular strategy is however expected to...

Discrete sizing and topology optimization of truss structures subject to stress and displacement constraints has been formulated as a Mixed-Integer Linear Programming (MILP) problem. The computation time to solve a MILP problem to global optimality via a branch-and-cut solver highly depends on the problem size, the choice of design variables, and t...

About 9% of anthropogenic greenhouse gas emissions worldwide are due to the production of cement, key constituent of concrete. Concrete also contributes to a large share of demolition waste, usually coming from building structures that are discarded because of functional obsolescence rather than of technical deficiency. Current practice for treatin...

Focusing on the cross-matching supply and demand for reused building components and related services, the paper analyses existing Digital Reuse Market Solutions (DRMS) in the European construction sector. A collection of 746 DRMS is built from major online circular economy platforms and custom online search queries. A taxonomy of 9 categories and 2...

As the most widely used construction material worldwide, concrete is the main cause of greenhouse gas emissions, material depletion, and waste generation by the construction industry. Typically, concrete waste is crushed and, at best, reclaimed into recycled aggregate or used as gravel. This process is energy-intensive and results in a reduction in...

The design and construction of doubly-curved structures often reveals to be challenging and can result in complex manufacturing and assembly. A recent strategy to tackle this difficulty consists in exploiting the connection between discrete differential geometry and constructive properties to identify curve networks with good fabrication or mechani...

Today, concrete is the most widely used construction material worldwide. Strong, versatile, durable, and vector of economic development, this exceptional material is also the principal cause of greenhouse-gas emissions, material depletion and waste generation by the construction industry. Hence, reusing concrete elements extracted from obsolete bui...

Stahl, ein wiederverwendbarer Werkstoff Die zerstörerischen Auswirkungen der Bauindustrie auf den Planeten und seine Bewohner sind inzwischen unbestritten. Der Klimawandel, die Abfallwirtschaft, die Verknappung der Bodenschätze, die Luft‐ und Bodenverschmutzung – all dies sind Themen, die dringend angegangen werden müssen. Sie stellen zudem eine He...

With the aim to reduce the environmental footprint of buildings, this paper presents an original structural system concept for two-way slabs in residential and office buildings. The proposed system extends the best practice in terms of modularity, versatility, demountability, reusability, and durability. A finite set of elements can be used to form...

Geodesic gridshells are shell structures made of continuous elements following geodesic lines. Their properties ease the use of beams with anisotropic cross-sections by avoiding bending about their strong axis. However, such bending may arise when flattening arbitrary geodesic grids, which forbids their initial assembly on the ground. This study pr...

Structural engineers play an increasing role in ensuring the transition towards a more sustainable construction sector: a) they are responsible for the design of the most resource- and energy-intensive part of buildings and infrastructure, and b) they regularly interact with architects, contractors, and clients, and hence are full stakeholders in t...

This paper presents a generative approach for the conceptual design of structures, which aims at exploring alternative bar networks in static equilibrium by means of a grammar rule. Operating on incomplete networks of bars in interim static equilibrium, the incremental rule application imposes the iterative introduction of a new node, some bar elem...

Designing structures from reused elements is becoming an increasingly important design task for structural engineers as it has potential to significantly reduce adverse environmental impacts of building structures. To allow for a broad application of this design approach, this paper presents an interactive computational tool to design structures fr...

The reuse of structural components in new buildings has great potential to reduce the environmental impacts of the construction sector but remains uncommon practice. An obstacle to its wider implementation is the lack of robust assessment methods and decision-making tools that consider the full spectrum of benefits and drawbacks. This paper propose...

Reusing structural components for multiple service cycles has potential to lower building structures environmental impact because it reduces material resource use, energy consumption, and waste production. One strategy to reuse structural components is to design structures that can be assembled, taken apart, and reassembled in new configurations. T...

This paper shows a computational workflow to design a kit of parts consisting of linear bars and spherical joints that can be employed to assemble, take apart and rebuild diverse reticular structures, e.g. gridshells and space frames. Being able to reuse bars and joints among different structures designed with this method reduces the material deman...

The design of envelopes with complex geometries often leads to construction challenges. To overcome these difficulties, resorting to discrete differential geometry proved successful by establishing close links between mesh properties and the existence of good fabrication, assembling and mechanical properties. In this paper, the design of a special...

Current load-bearing systems for buildings rarely have a beneficial end of life. Modular design is a proven solution for revalorizing obsolete structures, but it hardly competes with conventional solutions: the range of future spatial configurations that the modules will accommodate is usually too limited to balance additional upfront costs due to...

Design exploration frames the process of understanding design as a challenge and helps taming its complexity. It is a creative, but also paramount, process, that flourishes diversity, emergence and variability. The approaches used during this exploration stage can widen, or narrow, the domain where design variants can be found. Computational tools...

The building industry is responsible for 35% of all solid waste in Europe and more than a third of greenhouse gas (GHG) emissions. To address this, applying circular economy principles to the building sector is crucial, for example by reusing building elements from demolition sites rather than extracting and producing new materials. However, most c...

This paper presents optimization methods to design frame structures from a stock of existing elements. These methods are relevant when reusing structural elements over multiple service lives. Reuse has the potential to reduce the environmental impact of building structures because it avoids sourcing new material, it reduces waste and it requires li...

An important share of building environmental impacts is embodied in load-bearing structures because of their large material mass and energy-intensive fabrication process. To reduce substantially material consumption and waste caused by the construction industry, structures can be designed and built with reused elements. Structural element reuse inv...

Current studies and performance labels focus mainly on the operational energy demand of buildings due to heating, cooling, ventilation, lighting, and hot water, but they rarely account for embodied impacts. Performing a life cycle assessment (LCA) on an entire building structure, let alone a building, requires time and data, both of which are often...

Structural designers’ efforts to reduce environmental impacts traditionally consist of developing systems that minimise material quantities or use low-impact materials. A third strategy is currently (re)emerging: the reuse of structural components over multiple service lives and in new layouts. Still in its infancy, this circular economy strategy d...

This work proposes a new direction in structural design: the synthesis of structures through the reuse of elements. Reusing structural elements reduces the environmental impacts of building structures because it avoids sourcing new material, it reduces waste and it requires little energy. Designing structures from reused elements is unlike conventi...

This work fully investigates a specific timber joinery connection via experimental, analytical, and numerical methods. The selected joint is the Nuki joint: a mortised column with through-beam tenon. The experimental approach takes advantage of digital fabrication to reduce variations introduced by hand fabrication while the analytical approach bui...

A force-driven generative grammar rule is proposed as a design exploration method for planar networks in static equilibrium within non-convex domains. The aim is to enrich the catalog of unconventional structural typologies. Empty or partial networks in equilibrium are used as the starting point of the process. The rule's successive application alw...

Historic timber structures feature timber joinery connections that use interlocking geometries rather than fasteners. While timber construction since has gradually favored metallic fasteners, the longevity of historic timber structures utilizing joinery connections demonstrates their feasibility in structural systems and potential to enable sustain...

This paper presents structural optimization techniques to design truss structures that make best use of a given stock of structural components. Still little explored, the reuse of structural components over multiple service lives has the potential to significantly reduce the environmental impact of building structures. Structural design and constru...

This paper discusses the design of load-bearing systems for buildings with regard to their current lack of open-ended reusability. The reason for dismantling load-bearing systems today tends to be less related to material degradation than to a loss of functional fit with an evolving building program. It can therefore be expected that load-bearing c...

Load-bearing systems of buildings are poorly valued when they reach functional obsolescence. Still, they contribute the most to the material weight and embodied impacts of buildings and infrastructures. The reuse of structural components therefore offers great potential to save materials, energy and resources. While historic and contemporary projec...

This article develops a vector-based 3D graphic statics framework that uses synthetic and intuitive graphical means for the analysis and design of spatial structures such as networks of bar elements in static equilibrium. It is intended to support the collaborative work of structural engineers and architects from the conceptual phase of the design...

Historic timber structures feature timber joinery connections that use interlocking geometries rather than fasteners. While timber construction since has gradually favored metallic fasteners, the longevity of historic timber structures utilizing joinery connections demonstrates their feasibility in structural systems and potential to enable sustain...

This paper provides parametric estimates of embodied carbon reductions when structural components are reused in a typical office building. First, a lower bound of structural material quantities is estimated for a typical steel frame structure in a low-rise office building. The embodied carbon of this conventional design is then compared with values...

This case study applies life-cycle assessment methods to the preliminary design of an office building in order to quantify the benefits achieved when reusing its load-bearing components. Results show that the production of the load-bearing system would account for 40% of the global warming potential indicator. The slabs are responsible for 65% of t...

A known challenge of modular structural systems is to avoid the oversizing of its elements while allowing a wide variety of spatial layouts. Considering any given floor outline and the availability of square slab elements with three discrete bending and shear stiffness, this paper explores: 1) the minimal geometric and topological rules that ensure...

This paper investigates the structural performance of traditional moment-resisting interlocking timber joints for modern building construction. Gradually improved over generations, traditional Japanese and Chinese interlocking connections have proven structural integrity. In this paper, first, an overview of the development of historical Japanese a...

The building sector is one of the major contributors to material resource consumption, greenhouse gas emission and waste production. Load-bearing systems have a particularly large environmental impact because of their material and energy intensive manufacturing process. This paper aims to address the reduction of building structures environmental i...

This paper presents the design and construction of a 36m 2 gridshell, the rigidity of which is achieved through the bending of an initially flat grid of 210 reclaimed skis. The generated waste for its production is near zero as it is mostly built from discarded material. Its construction process is such that it can be disassembled and reassembled m...

The reciprocity between form and force diagrams in 2D graphic statics makes it possible to manipulate the form diagram while directly evaluating the redistribution of the forces within the force diagram. Conversely, after modifying the force diagram, the consequent transformation of the form diagram can be assessed at once. In the case of vector-ba...

This paper presents an extension of the Combinatorial Equilibrium Modelling (CEM) design framework. CEM gives the possibility to generate and explore multiple spatial equilibrium solutions in the early conceptual design phase. In addition to the form and force diagrams of graphic statics, CEM introduces a topological diagram, which allows to adjust...

One of the most crucial components of a tall building is its lateral loading system. In this paper, we provide the development of a lateral bracing system that results in bracing material savings of up to 50% relative to a traditional X-Bracing system, as well as lighter corner columns due to the more efficient load paths of the lateral forces to t...

The evaluation of the equilibrium of a system of forces that fulfills specified boundary conditions is a core question of theory of structures. This paper reviews three methods, related to procedures introduced at the end of the 19 th century, to evaluate the global equilibrium in three dimensions using graphic statics. The paper is specifically fo...

This paper presents an extension of the graphic-statics-based framework called Combinatorial Equilibrium Modelling (CEM). CEM allows for the generation of topologically and combinatorially different spatial equilibrium solutions in the early explorative design phase. In addition to the form and the force diagrams, CEM introduces a topological diagr...

This paper presents an approach to the extension of graphic statics force diagrams to the third dimension. The main focus is to build 3D force diagrams out of vectors, so that each edge in the form diagram corresponds to two parallel vectors in the force diagram; this pair of vectors can generally be overlapped to form one single edge. The issue of...

Direct methods that transform the geometry of a structure and conserve its static equilibrium are of particular interest for designers. They allow the exploration of alternative solutions at minimum computational cost. While parallel transformations (stretch, contraction, and skew) are easily understood and have been in use since long, nonparallel...

Structural robustness is related to the insensitivity of a structure to local failure, which is linked to the ability of force redistribution. Current approaches—probabilistic, risk-based, deterministic, and energetic—are poorly suited to inform the design of a structure at conceptual stage. Yet robustness issues must be addressed early in the desi...

This article presents a computational design methodology that integrates generative (architectural) and analytical (engineering) procedures into a simultaneous design process. By combining shape grammars and graphic statics, the proposed methodology enables the following: (1) rapid generation of diverse, yet statically equilibrated discrete structu...

This paper shares the authors’ experience regarding the Forces Frozen workshop developed in MIT’s Building Technology Program, within the Department of Architecture. This one-week outdoor workshop invites students to physically explore the world of structural ice shells. Ice shells are primarily created by a procedure that takes advantage of the sy...

Graphic statics has been strongly employed as a method to analyze and design structures. Whereas the former use is well documented in literature, the latter has been rarely discussed. Based on a close investigation of original working-drawings, this paper focuses on the graphical methods adopted by Luis Moya Blanco for the design of one of his most...

2016 Taylor & Francis Group, London. This paper shares the authors’ experience regarding the Forces Frozen workshop developed in MIT’s Building Technology Program, within the Department of Architecture. This one-week outdoor workshop invites students to physically explore the world of structural ice shells. Ice shells are primarily created by a pro...

This paper presents an extension of the graphic-statics-based framework called Combinatorial Equilibrium Modelling (CEM). CEM allows for the generation of topologically and combinatorially different spatial equilibrium solutions in the early explorative design phase. In addition to the form and the force diagrams, CEM introduces a topological diagr...

The evaluation of the equilibrium of a system of forces that fulfils specified boundary conditions is a core question of theory of structures. This paper reviews three methods, related to procedures introduced at the end of the 19th century, to evaluate the global equilibrium in three dimensions using graphic statics. The paper is specifically focu...

Graphic statics has been strongly employed as a method to analyze and design structures. Whereas the former use is well documented in literature, the latter has been rarely discussed. Based on a close investigation of original working-drawings, this paper focuses on the graphical methods adopted by Luis Moya Blanco for the design of one of his most...

In 1909, Rafael Guastavino Jr. designed the 93 feet diameter dome of the Cathedral of St John the Divine, Harlem; NY. As the thinnest brick shell in the world, the dome is also a clear example of construction efficiency and material optimization. This paper refutes the common idea that the original calculation notes are lost by showing that the pre...