Tools

South Sudan – State-of-the-Art on Flood Resilient Shelters

A. Ullal; X. Estrella

One of the most observable consequences of climate change is the abrupt increment in the number and intensity of seasonal floods. This has a special impact on vulnerable communities and developing countries that experience a strong impact on their housing infrastructure, leading to the displacement of communities on a seasonal basis. As a consequence, there is an imperative need for developing flood resilient solutions for housing in flood-prone areas. Therefore, this report presents the results of a comprehensive analysis of the current literature on flood resilient solutions so as to provide the basis for further research and development on the topic. Academic and practice reports were covered, aiming at providing a wide glance over the current developments on flood-resilient housing. The main aim of the work presented in this report is to provide an extensive review of constructions solutions developed to deal with seasonal floods, as well as common materials and detailings to reach such an objective. Besides, this document aims at presenting a first general glance to researchers and practitioners before developing specific solutions for a given region, acknowledging that due to cultural and material constraints, one-fits-all proposals are not a realistic solution in humanitarian scenarios.

2022-03-08

p. 20.

Test construction of first prototype with architecture students of Juba University, prior to field deployment (© Markus Zorn, November 2022)

on-site assessment

Concrete contributes to an important part of the total mass and embodied carbon in buildings. Regretfully, concrete building structures are rarely valued when they reach functional obsolescence. The reuse of reinforced concrete components from obsolete structures is therefore a promising strategy for reducing the material environmental impacts. One main challenge of this practice is to match new building projects with the available stock of reusable elements. We develop protocols for analyzing obsolete reinforced concrete structures, assess the reuse potential of their cut elements, and provide adequate information that eases the integration of these reused elements in new construction projects.

Facade of the Zürich Stadtspital Triemli Personalhäuser. Resource assessment with Zirkular.

Zürich Stadtspital Triemli Personalhäuser – Resource assessment of structural elements

J. R. Devènes; M. Bastien Masse; C. M. Küpfer; C. Fivet

The Triemli Personalhäuser are three equal 15-story buildings located on the Zürich Triemli Stadtspital campus and erected between 1964 and 1969. Cast-in-place reinforced concrete (RC) slabs and walls form the building cores and their surrounding corridors. The rooms are arranged around these cores. The load-bearing intermediate walls, made of prefabricated masonry, support thin precast slabs used as permanent forms. A RC layer is cast over these precast slabs and connects the room slabs with the cast-in-place slabs of the corridors and cores. The self-supporting facade consists of precast RC panels. The City of Zürich plans the deconstruction of these three buildings, thus making available a large amount of RC elements composing the structure and the facades of these buildings.
Little-known and rarely implemented, the reuse of concrete elements from obsolete buildings in new projects is a sustainable approach that promotes a circular economy. When reusing, the components of obsolete buildings are carefully dismantled without being crushed. They are then cleaned, possibly repaired or trimmed, and reused without many transformations in a new project, maintaining their shapes, technologies, and mechanical properties. In addition to maintaining the embodied energy and history of the reused components, reuse allows the construction industry to reduce demolition waste, greenhouse gas emissions, and material consumption.
This report is a preliminary resource assessment and aims at inventorying and assessing all structural elements of the Triemli Personalhäuser, focusing on their potential value for reuse. Both precast and cast-in-place RC elements are included. They are part of the load-bearing structure or are self-supporting such as the precast facade elements. The proposed methodology allows identifying all properties needed to evaluate the potential for reuse of an element: geometry, material properties, current condition, aesthetics, accessibility, resistance, future durability and environmental impacts. After reviewing available reports and drawings on the buildings, onsite visits are carried out to complete the information and visually inspect the structural elements. During the inspection, the elements are assessed with regards to their suitability for reuse and their condition is classified into a five-grade scale. The investigations are completed with destructive and non-destructive testing of the material properties.
Together, Buildings A, B and C are made up of approximately 7 000 m3 of materials constituting their load-bearing system, with approximately 2 500 m3 of precast concrete, 3 400 m3 of cast-in-place concrete and 1 100 m3 of masonry. Of this total, approximately 4% of the volume is dropped from the analysis due to the bad condition of the elements, namely the balcony slabs, the roof slab, and the external stairs. The other elements are in a good or acceptable condition and ae inventoried and analysed in detail.
The inventoried elements are divided into 5 categories: (1) facade elements; (2) slab elements; (3) wall elements; (4) column elements; and (5) staircases. Each of these categories are subdivided into a certain number of element types for which a complete factsheet is prepared, including pictures, drawings and useful information on their condition. The volume and weight of each element types are given, as well as their share of the total material volume. The embodied global warming potential (in kgCO2eq) for fabrication and demolition of the elements is also calculated. The results of the investigation on material properties confirm sufficient compressive strength for all elements. The carbonation depths measured on the cores are lower than the cover thickness of the reinforcement. Thus, the concrete is not carbonated in the reinforcement areas and the risk of corrosion is kept low, insuring a good durability of the elements.
This document should serve as a base for designing and planning future reuse applications for the concrete elements extracted when deconstructing the Triemli Personalhäuser. The information presented here will help the planners to prioritize the reuse strategy on the elements in the best conditions, with the largest volume share and thus with the largest embodied global warming potential.

2022

p. 90.

In collaboration with Charlotte Bofinger and Kerstin Müller from Zirkular.

Work in progress.
Contact: Maléna Bastien-Masse & Julie Devènes

reuse of cut concrete

Reinforced concrete is a wonderful construction material, enabler of the many technical feats that led to the creation of the built environment as we know it. Yet, cement is today responsible for about 9% of all man-made greenhouse gas emissions and concrete constitutes a major portion of waste. Urban densification worldwide leads to the premature demolition of too many reinforced concrete buildings that have yet to reach their design service life. Today, obsolete concrete parts are, at best, crushed and recycled into new concrete, which requires new cement production. We are exploring the potential of an alternative circular pathway in which obsolete reinforced concrete is cut with diamond-saws and/or dismembered with high-pressure water-jet, before being reused as fully operational load-bearing members.

The RE:CRETE footbridge is our prototype serving as a proof-of-concept. Funded by an ENAC Innovation Seed Grant, it uses 25 concrete blocks that were cut from a cast-in-place building currently under renovation in the region. The blocks were then assembled on a centering and with mortar in-between, in order to counteract with the wide variability in the block dimensions, which is characteristic of the reuse approach when compared with traditional manufacturing. Before removal of the centering, the thrust in the 10-m long arch was further increased with two post-tensioning cables running through the blocks centroids.

In terms of life-cycle assessment, the resulting arch provides a new lower-bound of global warming potential, far below any variant made of new material (concrete, steel, or even timber). The prototype also demonstrates that large amounts of concrete waste can be avoided by leveraging its load-bearing capabilities, while achieving a similar structural quality as a newly-produced concrete arch. This prototype opens up new directions to build with reinforced concrete … without pouring concrete.

Re:Crete – Reuse of concrete blocks from cast-in-place building to arch footbridge

J. R. Devènes; J. Brütting; C. M. Küpfer; M. Bastien Masse; C. Fivet

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 treating end-of-life concrete is to landfill it or crush it into aggregates used in new concrete mixes. Instead, a little-explored strategy consists in extending the service life of concrete elements by reusing them in new constructions. Following this paradigm, this paper presents a proof-of-concept prototype that reuses blocks cut out of obsolete cast-in-place concrete walls for a new structural application: a 10 m-long post-tensioned segmented arch footbridge. The paper details the design, material sourcing, and construction processes while highlighting the unusual features of the approach. The structural behavior is verified with a finite element analysis model and validated by load testing. A comparative life cycle assessment shows that the arch construction presents a significantly lower global warming potential then recycled concrete (−71%) or steel (−74%) alternatives and is very competitive to a timber one (+9%). In conclusion, the project proves the feasibility of a new circular economy application for the construction industry, in which new and reliable concrete structures are built with little to no cement inputs.

Structures

2022-09-01

Vol. 43 , p. 1854-1867.

DOI : 10.1016/j.istruc.2022.07.012

Short presentation by Maléna Bastien Masse (April 29th, 2022)

press kit download

EPFL mediacom article

EPFL mediacom video

Re:Crete in the news!

Construction process: cut on demolition site

Construction process: centering (back) and cut sections (front)

Construction process: placement of sections

Construction process: removal of the centering

Vernissage, October 11th, 2021, Smart Living Lab

Installation in Conthey, Wallis (April 14th, 2022)

Team:

design:
- Jan Brütting
- Maléna Bastien Masse
- Julie Devènes
- Maxence Grangeot
life-cycle assessment:
- Célia Küpfer
direction:
- Corentin Fivet
video:
- Maxence Grangeot
construction support:
- Claude-Alain Jacot
- Barbara Lambec
- Jonas Warmuth
- Raphäel Wegmann
- Xavier Estrella
- Numa Bertola
- Stéphane Pilloud
- Gavin Waddell
- Matias Cesari
- Augustin Pol

Funding:

ENAC Innovation Seed Grant
Canton of Wallis, CH
technical support from the Smart Living Lab

Industrial Partners:

More information will soon be released in scientific literature.

selective deconstruction / reversible construction

Selective deconstruction and reversible construction, i.e. the fact of ensuring on the one hand the dismantling of a pre-existing or future construction and on the other hand, the potential recovery of its spaces and elements beyond the first cycle of use of the building, are two necessary – but not sufficient – conditions for the construction industry to fully adopt a sustainable circular economy. As opposed to the usual practices of demolition and reconstruction, these two approaches encourage a safe and responsible attitude towards natural resources and ecosystems. On their own scale, they offer a better use of spaces and building elements at the end of their use cycle, a drastic reduction of demolition waste, a reduction in the extraction of raw materials, a contribution to the reduction of anthropogenic global warming and a guarantee of local job security.

Dismantling of the Rive's granary in Geneva, Switzerland, 1897 (credits: Boissonnaz, Geneva Library)

book download FR | Déconstruction sélective – Construction Réversible: recueil pour diminuer les déchets et favoriser le réemploi dans la construction

book download DE | Selektiver Rückbau – Rückbaubare Konstruktion: Studie zur Förderung der Abfallreduktion und der Wiederverwendung in der Baubranche

“Selective deconstruction – reversible construction: Compendium to decrease waste and encourage component reuse in the construction industry” is a book mandated by the Swiss Federal Office for the Environment (FOEN). Through a literature review, 32 case studies, and interviews with practitioners, the 160-page long book:

synthesises the fundamental principles of both approaches;
documents and disseminates feedback and good practice;
provides contractors, designers and clients with technical references;
provides stakeholders with a detailed, state-of-the-art theoretical background and a set of references to take them further;
outlines the prospects for development and opportunities applicable to the Swiss building sector.

The book is available in French and German, free to download on the FOEN’s official libraries (FR, DE) on waste management .

Déconstruction sélective – Construction Réversible: recueil pour diminuer les déchets et favoriser le réemploi dans la construction

A travers une revue de la littérature, ainsi que 32 études de cas et des entretiens avec des praticiens, ce recueil: › synthétise les principes fondamentaux des deux approches; › documente et diffuse les retours d’expériences et les bonnes pratiques; › apporte aux entrepreneurs/entrepreneuses, concepteurs/conceptrices et maîtrises d’ouvrage des références techniques; › procure aux parties prenantes un bagage théorique à la pointe et détaillé ainsi qu’une série de référence pour aller plus loin; › esquisse les perspectives d’évolution et opportunités applicables au bâti suisse.

Lausanne, Switzerland: EPFL, 2021-09-01.

DOI : 10.5281/zenodo.4314325

Selektiver Rückbau – Rückbaubare Konstruktion: Studie zur Förderung der Abfallreduktion und der Wiederverwendung in der Baubranche

Diese Sammlung stützt sich auf eine Literaturrecherche sowie 32 Fallstudien und Interviews mit Fachkräften und: › fasst die Grundprinzipien beider Ansätze zusammen; › dokumentiert und gibt Erfahrungsberichte und bewährte Verfahren weiter; › liefert technische Referenzen für Bauunternehmen, Entwerferinnen/Entwerfer und Bauherrschaft; › bietet einen aktuellen und detaillierten theoretischen Hintergrund sowie Referenzen für die weitere Entwicklung; › skizziert die Möglichkeiten zur Weiterentwicklung und Umsetzung für Schweizer Bauten.

Lausanne, Switzerland: EPFL, 2021-09-01.

DOI : 10.5281/zenodo.5131243

direction:

Corentin Fivet, EPFL

drafting:

Célia Küpfer, EPFL
Corentin Fivet, EPFL

new illustrations & copyright queries:

Julie Allémann, EPFL
Maxence Grangeot, EPFL
Célia Küpfer, EPFL

reviewing:

Julien Grisel, bunq architectes
Catherine de Wolf, EPFL
Maléna Bastien Masse, EPFL
Barbara Lambec, EPFL
Jan Brütting, EPFL

translation to German:

Nina Haftka, EPFL
Jan Brütting, EPFL

mandator:

Office Fédéral de l’Environnement ∙ http://www.ofev.ch
Division Déchets et Matières Premières
Section Cycles matières premières
CH-3003 Berne, Suisse
Dr. David Hiltbrunner (contact person)

Phoenix3D

Phoenix3D is a new open source Rhino3D + Grasshopper tool to design optimum truss structures made of new and reused components. It aims to support a more circular design approach in the structural design process. Thus, Phoenix3D enables to intuitively create and explore optimum structures in terms of environmental impact and other design goals. Its underlaying concept allows for real time feedback and fast design variations. Rather than one closed design loop, this tool is tailored to synergize with other Grasshopper components to guarantee a smooth design workflow.

Download

The tool is a plugin for Grasshopper3D, the interactive parametric environment within Rhino3D, a 3D modelling software widely used in architecture and structural design firms. The plugin is available via the PackageManager of Rhino3D. It is also available for download on Food4Rhino.

Installation

To install the plugin just search for “Phoenix3D” inside the PackageManager of Rhino3D. Then press the install button and re-launch Rhino. You’re all set up, enjoy!

Principle

Designing with reclaimed components swaps the conventional structural design process: rather than manufacturing components based on a preliminary design of the full structural system, the geometry and topology of the structural system is constrained by the availability of reused components. Hence the plugin demands the prior definition of two element stocks, one with the characteristics of elements that are available for reuse and the other with the characteristics of new elements regularly available on the market. The choice between both stocks when assigning the elements onto a predefined base structure is then processed through Best-Fit heuristics, allowing for the minimization of adverse environmental impacts or other objectives. The result is a structure whose topology and geometry is optimized for reusing the given stock of elements.

Tutorials

Tutorial 1: Basics

Tutorial 2: Parametric truss (coming soon)

Tutorial 3: Topology optimization (coming soon)

File examples

How to reference the tool

“Phoenix3D”, J. Warmuth, J. Brütting, C. Fivet, EPFL, 2021 (http://sxl.epfl.ch/Phoenix3D)

About the authors

The plugin is a product of the Structural Xploration Lab, EPFL. It is developed and coded by Jonas Warmuth & Jan Brütting following research results from Jan Brütting’s PhD thesis.

About the name

The phoenix is the immortal bird arising from the ashes of its predecessor. No other animal symbolizes better the extension of service lifespans of structural components through their reuse in new buildings.

Related publications

Computational Tool for Stock-Constrained Design of Structures
IASS Symposium, 2021 (detailed record)
Design of Truss Structures Through Reuse
Structures, 2019 (detailed record)

Open positions

Dismantling of a warehouse for reuse in the Halle 118 building, by Baubüro In Situ, Switzerland, 2019.

Postdoc Position on Robotic Reconfiguration of Timber Structures

As part of a collaborative research project between CRCL and SXL, we are looking for a highly motivated Postdoc Researcher starting Fall 2023. The 2-year project has been awarded the ENAC Interdisciplinary Cluster Grant and aims at combining the two labs’ expertise to develop sustainable construction methods. It particularly focuses on bringing together structural design, robotic construction and material reuse to successfully decrease construction waste. The project will focus on the reconfiguration of existing timber structures and investigate new methods of planning, designing, sequencing and robotic diss- and reassembly. The research will be conducted through a continuous feedback between digital design and physical prototyping at various scales. CRCL and SXL offer a robotics lab with several small-scale and large-scale industrial robots. The Postdoc Researcher will be hosted by both labs continuously.

We are looking for a Postdoc Researcher with a background in architecture or engineering (PhD degree) and experience in digital design and fabrication. The candidate should have good programming skills and enjoy working in a design related field.
The candidate should be self-driven and motivated to develop independent research in a collaborative environment. Excellent communication skills in English (both written and spoken) are mandatory. Experience with robots (industrial robots or bespoke robotic systems), sensing (computer vision and other sensors) and software development are a plus, but not mandatory.

Application link: https://recruiting.epfl.ch/Vacancies/2915/Description/2

Joint PhD Position with TU/Eindhoven on design tools to boost the uptake of reused materials in circular building.

Are you eager to work on advancing the transition to the circular building sector by developing new design tools and upscale the digital integration of reused materials and components in building design?

Do you have a master’s degree (or an equivalent university degree) in architecture, architectural engineering or related, with research experience? Are you familiar with computational design and modelling tools? Are you familiar with issues related to sustainability, such as life-cycle assessments, circular economy and other aspects?

As part of the Eurotech Universities Alliance, the TU/Eindhoven opens a PhD position with a secondment at the Structural Xploration Lab, EPFL. The PhD candidate will be co-advised by Torsten Schröder (TU/e) and Corentin Fivet (EPFL).

Application link: https://jobs.tue.nl/nl/vacature/phd-on-design-tools-to-boost-the-uptake-of-reused-materials-in-circular-building-993090.html
Screening starts on May 7th, 2023.

The SXL is always looking for bright-minded, talented, and passionate individuals to take part in its world-leading efforts in making component reuse techniques a new reality for sustainable construction. They are invited to submit spontaneous applications.

vernacular timber

We reexamine vernacular interlocking timber joinery.
Interlocking timber joinery (in opposition to geometries using fasteners) has been widely used in history thanks to a number of benefits that they provide: cuts are tailored for given geometries and load transfers; connections are reversible; timber elements are disassembled and cut again for new purposes; hence allowing their reuse in new configurations. However, all available geometries for post-and-beam applications are results of incremental refinement through the ages. How should one adapt them for today’s needs? Also, what can we learn from discontinued technical solutions in vernacular timber architecture?

The zaojing: review of a unique wooden construction typology

J. Ye; C. Fivet

The zaojing is an ancient Chinese construction system consisting of a dome-shaped assembly of interlocked wooden pieces. These structures are placed above live performance spaces to enhance sound diffusion while creating background scenery. Existing zaojings in China display a diverse range of geometric expressions, construction details, and structural behaviours. Despite their uniqueness and historical interest, very little literature about the zaojing is known to exist, and what does is not comprehensive. Building on recent field investigations in rural China, this paper sheds new light on zaojings. Following a summary of ancient Chinese construction practice, a comprehensive list of publications on zaojings is first reviewed. The paper then identifies differences between various zaojings and suggests a typological classification. Construction details and repair practices are eventually described. In conclusion, the study brings forward the typological diversity of the zaojing, a unique wooden ceiling system whose significance in the history of wood joinery construction has not yet been fully appreciated.

International Journal of the Construction History Society. 2020-06-30. Vol. 35, num. 1, p. 23-49. DOI : 10.5281/zenodo.3941502.

Renovation of a Zaojing built in 1829 in Ninghai, China. Credits: Xiaodong Chai

Related publications:

The caisson – review of a unique wooden construction typology in China
International Congress on Construction History 2018 (detailed record)
Restoration of ancient Chinese opera spiral wooden domes, accounts of field practice
IIWC Symposium 2018 (detailed record)
The ancient Chinese opera spiral wooden domes
CHS conference 2019 (detailed record)

Modern timber design approaches for traditional Japanese architecture: analytical, experimental, and numerical approaches for the Nuki joint

D. Fang; J. Moradei; J. Brütting; A. Fischer; D. K. Landez et al.

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 builds on state-of-the-art embedment stress models. Material tests are used to calibrate the non-linear finite element model and analysis of the connection. Furthermore, the difference in behavior between prototypes of various beam thicknesses is examined across analysis approaches. This work not only sets out a workflow for digital fabrication, physical testing, and structural analysis for more complex joinery geometries, but also discusses the challenges and relevance of its application towards a reference library of joinery connections for modern timber construction.

2019-10-07. 60th-Anniversary Symposium of the International Association for Shell and Spatial Structures, Barcelona, October 7-10, 2019. p. 2911-2918.

Nuki joint: experimental testing, analytical model, and numerical simulation.

Related publications:

Rotational stiffness in timber joinery connections: Analytical and experimental characterizations of the Nuki joint
ICSA conference 2019 (detailed record)
Reconsidering traditional timber joinery for sustainable structures
RCA conference 2019 (detailed record)
Structural Characterization of Traditional Moment-Resisting Timber Joinery
IASS symposium 2018 (detailed record)

multi-purpose kits of parts

We develop algorithms to synthesize kit-of-part structures whose components can be reused in diverse shapes.
Structures today are designed for a single life cycle. When they become obsolete, their components are lost and all adverse environmental impacts related to their existence becomes meaningless. What if structural components were designed not for one application but for a series of applications? What if they could be reassembled to form extremely diverse geometries and topologies, without large oversizing?

Synthesis of Kit-of-parts Structures for Reuse

J. Brütting; G. Senatore; A-M. Muresan; I. Mirtsopoulos; C. Fivet

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 demand compared to one-off construction. The input of the method is a set of different reticular structures intended to be built from a common kit of parts. In a first step, the structure geometries are optimised such that the structures share groups of members with identical lengths to allow the placement of same bars in all structures. In a second step, the kit-of-parts joints are optimised to allow their reuse in different structures as well. This is achieved by merging the specific connection patterns of nodes from different structures into one joint. The potential of the proposed method is demonstrated via its application to two case studies: 1) the design of three temporary space frame roofs, and 2) the realisation of three pavilion-scale prototypes serving as a proof of concept. The latter case study also shows the robotic fabrication of the bespoke joints.

2021-04-29. Advances in Architectural Geometry 2020, Paris, France, April 26-29, 2021.

Reusable spherical joint for space frame applications.

Design and fabrication of a reusable kit of parts for diverse structures

J. Brütting; G. Senatore; C. Fivet

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. This paper presents a new computational workflow to design a bespoke kit of parts that can be employed to build structures of diverse typologies and that are not restricted to repetitive modular arrangements. Key to this method is the optimization of structural members and joints (i.e. the kit of parts) that fit multiple geometries and different structural requirements. The proposed method includes form finding and digital fabrication and it applies to the design of trusses, gridshells, and space frames. This method has been successfully applied to build three pavilion-scale prototypes from only half the number of parts compared to one-off construction.

Automation in Construction. 2021-03-04. Vol. 125, p. 103614. DOI : 10.1016/j.autcon.2021.103614.

Kit-of-parts design and fabrication. (a) a kit of parts to build three structures – bars and joints are reused among structure assemblies, (b) realized pavilion-scale prototypes.

Form follows availability – Designing structures through reuse

J. Brütting; G. Senatore; C. Fivet

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 conventional structural design because stock element availability is a design input. In other words, structures must be designed subject to availability of given element characteristics such as length and cross-section type, which have a major influence on the optimal structure layout and form. In this new paradigm structural form follows availability. In this work new computational methods for the synthesis of reticular structures through reuse are formulated to address two scenarios: a) reuse of reclaimed elements from a given stock, and b) design of an element stock which is used as a kit of parts to build diverse structures. Case studies are presented to demonstrate the potential of the proposed methods. It is shown that structures produced by these methods have a significantly lower environmental impact than minimum weight structures made of new elements.

Journal of the International Association for Shell and Spatial Structures. 2019. Vol. 60, num. 4, p. 257-265. DOI : 10.20898/j.iass.2019.202.033.

Designing structures through reuse: three trusses made from one kit of parts.

Optimal kit-of-parts design: (top) optimal geometries and element assignment, (bottom) element assignment and stock description, ordered by cross-section size

Other publications:

Exploration of spatial structures made from reused elements and the design of optimal kits-of-parts
ICSA conference 2019 (detailed record)

optimum reuse

We develop algorithms to synthesize structural layouts with optimized reuse rate.
Reusing structural elements entails reversing the conventional structural design process. The mechanical and geometric properties of available elements predetermine the layout of a structure, in other words: form follows availability. The operation is one that can be optimized computationally. What is the best way to assign reclaimed members into a structural system? What is the best topology and geometry of a system in order to best reuse a given stock of elements? How much savings can be achieved in terms of environmental damage?

The Material Testing Facility (Busby and Associates, Fast+Epp, 1999, Vancouver, Canada) reclaims heavy timber structural members from former warehouses on the site.

See also our page on Phoenix3D for the interactive Grasshopper plugin that builds on the algorithms described on this page.

Environmental impact minimization of reticular structures made of reused and new elements through Life Cycle Assessment and Mixed-Integer Linear Programming

J. Brütting; C. Vandervaeren; G. Senatore; N. De Temmerman; C. Fivet

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 involves: element sourcing and deconstruction, reconditioning and transport. As these processes also generate environmental impacts, reuse might not always be preferred over new construction. This paper presents a method to design reticular structures with minimal environmental impact made from reused and new elements. The formulation given in this paper is based on a combination of Life Cycle Assessment (LCA) and discrete structural optimization. The LCA carried out in this work accounts for impacts generated from sourcing reclaimed elements to the assembly of the structure. Structural optimization is subject to stress constraints on element capacity and deflection limits for serviceability. Typical loading scenarios are considered. The method is applied to the design of three single-span steel trusses of different topology subject to 100 simulated stocks of reusable elements that have varying cross-sections and lengths. Benchmarks against minimum-weight solutions made solely from recycled steel show that this method produces structures with up to 56% lower environmental impact. Depending on stock availability, the lowest environmental impact is achieved through a combination of reused and new elements.

Energy and Buildings

2020

Vol. 215 , p. 109827.

DOI : 10.1016/j.enbuild.2020.109827

Optimal design of structures from reused and new elements (primary and secondary steel)

Shares of environmental impact for each structure and scenario.

Design of Truss Structures Through Reuse

J. Brütting; J. Desruelle; G. Senatore; C. Fivet

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 construction based on reuse avoids sourcing new material, it reduces superfluous waste, and requires little energy. However, designing a structure from a stock of reclaimed elements entails a change of design paradigm: in contrast to conventional design practice, the structural geometry and topology depends on element stock characteristics, e.g. available cross sections and lengths. This paper presents discrete structural optimization formulations to design truss systems from stock elements. The approach taken in this work is iterative: 1) element assignment and topology optimization are carried out, and 2) geometry optimization follows thereafter to best-fit the system geometry to the length of assigned stock elements, for instance to reduce cut-off waste. Two case studies are presented: a) a cantilever of simple layout used to explain the details of the design methodology, and b) a train station roof structure of complex layout made from elements reused from disassembled electric pylons. For these case studies, Life Cycle Assessment confirms that an up to 63% environmental impact reduction is possible when comparing structures obtained with the proposed method against weight-optimized solutions made of new elements.

Structures. 2019. Vol. 18, p. 128-137. DOI : 10.1016/j.istruc.2018.11.006.

Schematic view of the intended roof truss design, using elements from electric pylons.

Optimum design of frame structures from a stock of reclaimed elements

J. Brütting; G. Senatore; M. Schevenels; C. Fivet

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 little energy. When reusing elements, cross-section and length availability have a major influence on the structural design. In previous own work, design of truss structures from a stock of elements was formulated as a mixed-integer linear programming (MILP) problem. It was shown that this method produces solutions which are global optima in terms of stock utilization. This work extends previous formulations to stock-constrained optimization of frame structures subject to ultimate and serviceability limit states hence expanding the range of structural typologies that can be designed through reuse. Fundamental to this method is the globally optimal assignment of available stock elements to member positions in the frame structure. Two scenarios are considered: A) the use of individual stock elements for each member of the frame, and B) a cutting stock approach, where multiple members of the frame are cut from a single stock element. Numerical case studies are presented to show the applicability of the proposed method to practical designs. To carry out the case studies, a stock of elements was inventoried from shop drawings of deconstructed buildings. Results show that through reusing structural elements a significant reduction of embodied greenhouse gas emissions could be achieved compared to optimized structures made of new elements.

Frontiers in Built Environment. 2020-05-27. Vol. 6, num. 57, p. 1-18. DOI : 10.3389/fbuil.2020.00057.

a) locations of the stock elements, building site, new steel supplier and steel manufacturer; b) disassembly of a steel structure at location S1; c) stockpile of reclaimed steel elements.
Map (a) by (Tschubby, 2005) CC-BY-SA 3.0; pictures (b) and (c) courtesy of baubüro in situ, Basel, Switzerland.

Optimal cross-sections and cutting pattern of reused stock elements.

Form follows availability – Designing structures through reuse

J. Brütting; G. Senatore; C. Fivet

Journal of the International Association for Shell and Spatial Structures. 2019. Vol. 60, num. 4, p. 257-265. DOI : 10.20898/j.iass.2019.202.033.

A spatial truss made from a stock of reclaimed elements

Optimum spatial designs from given stocks: system definition, optimal solutions from stocks A, B, and C, minimum weight solution with new elements.

Other publications:

Computational Tool for Stock-Constrained Design of Structures
IASS symposium 2021 (detailed record)
Form follows availability – Designing structures through reuse
IASS symposium 2019 (detailed record)
Exploration of spatial structures made from reused elements and the design of optimal kits-of-parts
ICSA conference 2019 (detailed record)
The reuse of load-bearing components
SBE 2019 (detailed record)
Optimum Truss Design with Reused Stock Elements
IASS symposium 2018 (detailed record)
Optimization Formulations for the Design of Low Embodied Energy Structures Made from Reused Elements
EG-ICE conference 2018 (detailed record)

Circular Structural Design

We delineate the circular future of structural design (and its past).
Circular Economy concepts are gaining momentum worldwide. Their benefits for the environment and employment have been demonstrated. Still, their implementation in the construction industry is yet to be explored. What would a circular construction industry be like? What are the new opportunities and challenges for building designers? To what extent can circular economy be achieved? How far does it affect the design of load-bearing systems in buildings? What can we learn from past attempts?

Crystal Palace (Richard Paxton, 1851) (Photograph by Philip Henry Delamotte) — Although meant for reuse, the Crystal Palace (Richard Paxton, 1851) suffered from inappropriate technological details. (Photograph by Philip Henry Delamotte)

Nothing is lost, nothing is created, everything is reused: structural design for a circular economy

C. Fivet; J. Brütting

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 disrupts structural design practice in many ways: rather than manufacturing components after the design of a system, the system is synthesised from a given stock of reclaimed components; versatility, reversibility and transformability become hard requirements for all loadbearing systems and components; costs, performance and environmental assessments span multiple service lifecycles. There is consequently a sudden lack of expertise, design tools, technological solutions and relevant metrics. This article contextualises the effects of the circular industrial economy upon structural design practice and reviews recent and future developments in the field.

The Structural Engineer. 2020-01-02. Vol. 98, num. 1, p. 74-81.

We identify reusable components as a new design mean
to reduce the adverse environmental impacts of building structures.

A 100 yr-old barn built with 200 yr-old beams

Other publications:

Corentin Fivet : Sortir de l’esthétique du bricolage
Tracés magazine, 2019 (detailed record)
Design of Load-Bearing Systems for Open-Ended Downstream Reuse
SBE conference 2019 (detailed record)
The reuse of load-bearing components
SBE conference 2019 (detailed record)

environmental indicators

We quantify reusability and material usage in building structures.
Buildings represent over a third of global anthropogenic greenhouses emissions. Load-bearing elements are the biggest contributor to the embodied carbon of buildings. New pathways for its reduction are to be found in order to avoid extreme climate catastrophes. However, the task of designing buildings remains very complex and environmental measures often contradict each other. How good is a new design? Is it actually better and more appropriate than previous ones? How can we objectively assess the environmental benefits gained when reusing load-bearing components over multiple life-cycles?

mapping Geneva’s embodied carbon legacy

Decisions on future developments too often result from no to little understanding of the historical development that has led to that current situation. Understanding the past to better shape the future is a known adage that is however harder and harder to apply because of data proliferation. Any synthetic, user-friendly, representation of the past is therefore key to its interpretation. Compared to other productions of the humankind, the built environment has a particular grip on space and time: built artefacts have a long service life and they shape the spatial context of human activities in many ways. As of today, little is available when it comes to assess the embodied carbon related to urban developments. We here apply a new, bottom-up methodology, to assess the embodied carbon over time and space, in the limits of the canton of Geneva. This project is carried within the Habitat Research Center and contributes to the DHLab Time Machine.

Publication under review.

Corentin Fivet
Catherine De Wolf
Thibaut Menny
Serena Vanbutsele

Decision Framework to Balance Environmental, Technical, Logistical, and Economic Criteria When Designing Structures With Reused Components

C. Küpfer; N. J. Bertola; J. Brütting; C. Fivet

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 proposes a multi-criteria decision framework that builds on a simulated set of design alternatives with varying ratios of reused and new structural components. A set of performance criteria is presented, addressing procurement risks, construction technique complexity, environmental impacts, and project costs. As the independent criterion evaluations often deliver conflicting results, a multi-criteria decision analysis helps identify the most appropriate solution. The design of a steel Pratt truss is used as a case study to demonstrate the applicability of the framework. Different alternatives with reuse rates above 65% are recommended for each preference scenario, reducing between 35 and 45% of adverse environmental impacts in comparison to an equivalent design made of new elements only. The study underpins the principle that there is no trivial and unique best option when designing with reused components. Multi-criteria decision analyses applied to structures with varying reuse rates constitute a promising tool to support decision-makers.

Frontiers in Sustainability

2021

Vol. 2 , p. 689877.

DOI : 10.3389/frsus.2021.689877

Comparison of reuse alternatives. A Summary of the design options. Gray bars correspond to reused components and blue bars to new components; B evaluation of the four options for different performance criteria.

Comparison of environmental assessment methods when reusing building components: a case study

C. E. L. De Wolf; E. Hoxha; C. Fivet

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 current life-cycle assessment (LCA) tools are not appropriate to evaluate the environmental impact of a building when its components originate from prior buildings and/or will be used in future unknown ones. Still, robust measurement is needed to demonstrate the benefits of reuse towards environmentally sustainable cities. This paper compares existing methodologies to quantify the global warming potential (GWP, expressed in kgCO2e/unit) of recycled/recyclable and reused/reusable products, selected within widely recognised standards, rating schemes, and academic studies, such as the cut-off method, the end-of-life method, the distributed allocation (PAS-2050) method, the Environmental Footprint method, the Degressive method and the SIA 2032 method. Based on these recognised approaches for assessing the GWP of products, new equations are written and applied to buildings with reused/reusable materials for each of the methods. The Kopfbau Halle 118 building (Winterthur, CH, 2021), which is designed with reclaimed elements from local demolition sites, is chosen as a case study. Discrepancies in LCA methods are highlighted by applying them to three different life cycles corresponding to the first, intermediate, or final use of building components. This paper shows that current quantification methods to assess reuse give wide-ranging results and do not address the full spectrum of the reuse practice, that their boundaries are too limited, and that a number of critical features are currently hardly quantifiable, such as embedded use value, versatility, storage and transformation impacts, user-owner separation, dis/re-mountability, or design complexity.

Sustainable Cities and Society

2020

Vol. 61 , p. 102322.

DOI : 10.1016/j.scs.2020.102322

[email protected]
+41 21 693 71 42

Global Warming Potential per gross floor area of the entire studied building for each typical life-cycle.

Other publications:

Database of Embodied Quantity Outputs: Lowering Material Impacts Through Engineering
Journal of Architectural Engineering 2020 (detailed record)
Embodied Carbon Benefits of Reusing Structural Components in the Built Environment: a Medium-rise Office Building Case Study
PLEA conference 2018 (detailed record)
Environmental Benefits when Reusing Load-Bearing Components in Office Buildings: A Case Study.
PLEA conference 2018 (detailed record)
Can timber lower the environmental impact of tall buildings?
ICSA conference 2019 (detailed record)

Contact

direction:

[email protected]

administration:

mailing address:

smart living lab / EPFL Corentin Fivet
Passage du Cardinal 13B
CH-1700 Fribourg
Switzerland

visits in Fribourg:

smart living lab · room HBL-3C and room HBL-0-42A
directions once on the Blue Factory site

visits in Lausanne:

EPFL main campus · room BP 3 224

Team

Corentin Fivet · Professor / Lab Head

Corentin’s research and teaching are driven by the need for more sustainable building systems. Merging architecture, structural design, and construction science, his work explores new circular implementations of load-bearing systems and new design methods for resource-efficient structural typologies.

Assistant Professor @ EPFL since 2016 | Postdoctoral researcher & lecturer @ MIT 2014-2016 | PhD in Engineering Sciences @ UCLouvain 2009-2013 | Architecture internship @ Charles Vandenhove, Belgium 2008-2009 | Bachelor and Master in Architectural Engineering @ UCLouvain 2003-2008.

Maléna Bastien Masse · Scientific Collaborator

Malena’s research interest covers the preservation and strengthening of existing structures as well as sustainable and circular solutions for the construction industry. At the Structural Xploration Lab, Malena works on the reuse potential of architectural components in the Swiss building stock

Project leader, structural and civil engineer @ INGPHI SA 2016-2020 | PhD in civil engineering @ EPFL 2011-2015 | M.A.Sc. and B.Eng in civil engineering @ PolyMontréal 2004-2010.

Xavier Estrella · Postdoctoral Researcher

Xavier’s research interests span a wide range of fields in structural engineering, such a structural dynamics, non-linear modeling, seismic protection solutions, mid- to -high-rise timber buildings, eco-friendly structural solutions, circular economy, among others.

PhD in Engineering Sciences @ Pontifical Catholic University of Chile 2016-2020 | Master in Quality Management and Evaluation in Higher Education @ Universitat Oberta de Catalunya 2018-2019 | Bachelor of Engineering: Civil Engineering, Administration and Construction Management @ University of Azuay 2010-2015.

Léa Boulic · Lecturer

Léa’s interests include the interplay of forces and forms in architectural design and how the structural dimension of a project can contribute to defining and strengthening its architectural concept.

Lecturer @ EPFL since 2021 | Postdoc @ ETHZ 2020 | PhD in Architecture @ ETHZ 2016-2019 | Diplôme d’Etat d’Architecture @ ENSA Nantes 2009-2014 | Diplôme d’Ingénieur @ Ecole Centrale de Nantes 2009-2012

Pierre Zurbrügg · Lecturer

Building on his own practice, Pierre teaches construction technology, building materials, building services and building renovation to bachelor and master students in Architecture. He joined SXL in September 2021.

Teresa Messina · Administrative Assistant

Teresa joined EPFL in September 2022. At SXL she ensures the success of every administrative process.

Jingxian Ye · PhD Candidate

Jingxian is interested in the research of architectural and structural principles, and their construction logics. Inspired by master builders and learning from the past, Jingxian is pursuing a PhD on component reuse in traditional construction systems and its relevance for contemporary and future applications.

PhD candidate in Architecture @ EPFL since 2019 | member of the ICOMOS International Wood Committee since 2018 | Professional architect since 2016 | Master in Architecture @ ETHZ 2011-2015 | Bachelor in Architecture @ Tongji University 2005-2010

Célia Küpfer · PhD Candidate

Célia nurtures an interest for reuse in architecture since her master thesis, which was awarded an Orlando Lauti Foundation Award. She has been awarded a Doc.ch grant to pursue doctoral research on novel evaluation methods for reuse in architecture.

PhD candidate in Architecture @ EPFL since 2020 | Bachelor and Master in Architecture @ EPFL 2012-2019 | Architect Intern @ Atelier Bow-Wow Tokyo 2016 | Exchange year @ University of Montreal 2014-2015.

Barbara Lambec · PhD Candidate

Barbara developed a passion for banal architecture and its necessary ingenuity linked to the economy of means. She is currently pursuing research on evaluating the reuse potential of architectural components in the Swiss building stock.

PhD candidate in Architecture @ EPFL since 2020 | DSA Patrimoine @ ENSA Paris Belleville 2013-2015 | Licence, ADE, and HMONP @ ENSA Marne la Vallée 2007-2013 | Année d’échange @ TU Eindhoven 2010-2011.

Raphaël Wegmann · PhD Candidate

Raphaël’s research interests span a variety of fields, such as Computer Simulation, Statistical Learning, and Circular Economy. He is currently pursuing a PhD on evaluating the reuse potential of architectural components in the Swiss building stock.

PhD candidate in Civil Engineering @ EPFL since 2020 | MRes in Engineering @ University of Cambridge 2018-2019 | MSc in Civil Engineering @ ETHZ 2014-2017 | BSc in Civil Engineering @ EPFL 2011-2014.

Jonas Warmuth · PhD Candidate

Jonas is interested in form-finding and optimization techniques for the conceptual design of structures. He concentrates his research on the development of computational tools and methods intended to support architects and engineers in early design stages.

PhD candidate in Civil Engineering @ EPFL since 2020 | Master in Structural Engineering @ TU Munich 2017-2020 | Exchange master project @ ETHZ 2019-2020 | Bachelor in Structural Engineering @ Erfurt Institute of Technology 2013-2017.

Maxence Grangeot · PhD Candidate

Maxence’s research explorations relate to digital-analog fabrication and structural reuse. At SXL, he participates to various research and teaching activities, and conducts a PhD thesis on new means of fabrication for upcycling structures.

Maria Sivers · Affiliated PhD Candidate

Maria is passionate about the circular economy ideas and reuse in the construction sector, combined with entrepreneurship and innovations. She is a fellow of the EPFLInnovators Programme co-funded by Marie Skłodowska-Curie.

PhD candidate in Architecture @ EPFL since 2019 | Project manager & entrepreneur since 2011 | Internship @ Parliament of Ukraine | Research assistant @ KNUBA 2009-2019 | Research exchange @ TU Munich 2008-2009 | Professional architect since 2005 | Bachelor & Master in Architecture and Reconstruction @ KNUBA/ University of Kyiv 1999-2005.

Julie Devènes · Scientific assistant

Julie is interested in solutions to reduce construction’s environmental impact, especially in the field of concrete structures. During her master’s project her focus was in the reuse of concrete for the design of pedestrian bridges. She continues to explore the subject through a Master Valorization at the Structural Xploration Lab.

Master Valorization @EPFL since 2021| Master in Civil Engineering with a specialization in Structural Engineering @EPFL 2018-2021| Bachelor in Civil Engineering @EPFL 2015-2018.

Nicole Widmer · Scientific assistant

Nicole aims at developing structural solutions to reduce the environmental impact of construction and implement a circular economy, in particular in the field of concrete structures. Her master’s project focused on load-bearing structures made of reused concrete elements. She continues to explore the subject through a Master Valorization at the Structural Xploration Lab.

Master Valorization @EPFL since 2022| Master in Civil Engineering with a specialization in Structural Engineering @EPFL 2020-2022| Bachelor in Civil Engineering @EPFL 2017-2020.

alumni

postdocs

Jan Brütting (2016-2021 | struct.eng. @ Schlaich Bergermann P.)
Catherine De Wolf (2017 – 2020 | professor @ ETH Zürich)
Endrit Hoxha (2017 | professor @ Aalborg University)
Sofia Colabella (2016 – 2017 | lecturer @ Univ. of Melbourne)

PhDs

Ioannis Mirtsopoulos (2018-2022)
Jan Brütting (2016-2021)

scientific collaborators

Alex Muresan (2017-2020 | founder at Aeternum Technologies)

interns

Augustin Pol (Spring 2022 – arch. UCLouvain)
Nina Haftka (Spring 2021 – arch. EPFL)
Julie Allémann (Summer 2020 – arch. EPFL)
Maxence Grangeot (Summer 2020 & Winter 2021 – arch. EPFL)
Joar Chouaki (Winter 2019 – master ENPC)
Thibaut Menny (Winter 2018-2019 – arch. EPFL)
Kevin Mureno (Spring 2019 – master UPC, ES)
Tess Hegarty (Summer 2018 – PhD Stanford University, USA)
Berenice Vallance (Summer 2018 – INSA Strasbourg, FR)
Federico Broggini (Summer 2018 – arch. Mendrisio, CH)
Luca Sironi (Summer 2018 – Politecnico di Milano, IT)
Javier Cañada (Spring 2018 – ETSI CCP Madrid, ENPC Paris)
Joseph Desruelle (November 2017 to March 2018 – EPFL)
Jingru Zhong (August to November 2017, China)
Setare Seraj (September 2017 – bachelor AUT, Iran)
Shayegan Shakeri (September 2017 – bachelor AUT, Iran)
Julieta Moradei (June & July 2017 – UC Berkeley, USA)
Jacopo Orlandi (March to June 2017 – master Roma Tre, Italy)
Valeria Didonna (Dec. 2016 to June 2017 – Univ. of Bari, Italy)
Mélanie Lacroix (September 2016 – Arch. EPFL)
Yann Junod (September 2016 – Arch. EPFL)

Publications

Books

Selektiver Rückbau – Rückbaubare Konstruktion: Studie zur Förderung der Abfallreduktion und der Wiederverwendung in der Baubranche

Lausanne, Switzerland: EPFL, 2021-09-01.

Déconstruction sélective – Construction Réversible: recueil pour diminuer les déchets et favoriser le réemploi dans la construction

Lausanne, Switzerland: EPFL, 2021-09-01.

C. M. Küpfer; M. Bastien Masse; C. Fivet

Reviews

Reuse of concrete components in new construction projects: Critical review of 77 circular precedents

J. Ochsendorf; T. Helbig; C. Fivet; J. Yoon

Detail Structure. 2016. Vol. 2016, num. 1, p. 67-73.

Design and exploration of externally post-tensioned structures using graphic statics

L. Todisco; C. Fivet; H. Corres Peiretti; C. Mueller

Journal of the International Association for shell and Spatial Structures. 2015. Vol. 56, num. 4, p. 249-258.

A geometrical approach to evaluating constitutive elements of structural robustness

A. Deschuyteneer; D. Zastavni; C. Fivet

IABSE Report. 2015. num. 103, p. 210-217.

A fully geometric approach for interactive constraint-based structural equilibrium design

Computer-Aided Design. 2015. Vol. 61, p. 42-57. DOI : 10.1016/j.cad.2014.04.001.

Constraint-Based Graphic Statics: New paradigms of computer-aided structural equilibrium design

Journal of the International Association for Shell and Spatial Structures. 2013. Vol. 54, num. 4, p. 271-280.

Robert Maillart’s Key Methods From the Salginatobel Bridge Design Process (1928)

Journal of the International Association for shell and Spatial Structures. 2012. Vol. 53, num. 1, p. 39-47.

B. Jacot; D. Pagonakis; M. Shope; C. Fivet; J. Ochsendorf

D. Zastavni; J-F. Cap; J-P. Jasienski; C. Fivet

2014. IASS-SLTE 2014 Symposium, Brasilia, Brazil, September 15-19, 2014.

Various perspectives on the extension of graphic statics to the third dimension

J-P. Jasienski; C. Fivet; D. Zastavni

2014. IASS-SLTE 2014 Symposium, Brasilia, Brazil, September 15-19, 2014.

Constraint-Based Graphic Statics: New paradigms of computer-aided structural equilibrium design

2013. International Association for Shell and Spatial Structures (IASS) Symposium 2013: Beyond the Limits of Man, Wroclaw University of Technology, Poland, September 23-27, 2013.

UCLouvain.be, 2013.

Patents

Load bearing device

C. Fivet; D. Redaelli; A-M. Muresan; J. Brütting

2012

AR-128 Building Technology I, II

Education

The Structural Xploration Lab is involved in the teaching of architectural structures at ENAC. Our teaching philosophy places the focus on design processes rather than problem solving, at the border of synthetic and analytic thinking. We provide students with the required tools, methods and theories that will allow them to confidently steer the decision process related to the shaping of construction systems. We emphasize a clear understanding of the principles and their assumptions, with the goal of letting students develop their creativity at full scale but within safe bounds with regards to effective constructability and environmental challenges. We believe in the full collaboration of building professionals at every stage of the design process, as well as during the education of architects and engineers.

bachelor topics

Introduction to the art of building: environmental and societal challenges, functional and technical requirements of buildings, static behavior of structures, construction materials and their geometric implementation, historico-cultural contextualization of the construction practice, sustainability strategies and circular economy.

AR-241/AR-242 Building Technology III & IV

Theoretical and case-based developments on the practice of building construction. Analysis and synthesis of the fields of building physics, structural design, building materials and technical installations.

PENS-212 Constructive Second-Hand

ENAC week workshops bring together bachelor students in architecture, civil engineering and environmental engineering. Constructive Second Hand considers circular economy as an opportunity to better design while reclaiming wasted elements. For a whole week, students are invited to the Smart Living Lab in Fribourg, CH. Each group has one goal: to build a piece of furniture while reusing discarded elements from local industries. The week gives full autonomy to the student groups and is comprises three steps: material collection, design & construction, and demonstration. A jury eventually discusses how embedded functional and technical qualities are reclaimed, as well as the potential for large-scale repeatability.

master topics

AR-497 Building Design in the Circular Economy

Circular economy consists in maintaining and/or improving the value of products as long as possible, i.e. by extending or renewing their service live while minimizing resource depletion, waste generation, and greenhouse gas emissions. When it comes to building design, a series of sometimes contradicting strategies emerges: to limit the quantity of used materials, to limit their ecological impact, to enhance the versatility of buildings, and to ensure the future repair, reuse, or recycling of their components. The class delves into recent literature and practice, aiming at providing the necessary expertise to adopt these strategies in a pragmatic state of mind.

AR-483 Interactive Conceptual Design of Structural Forms

The class exposes students to the geometric design of unconventional low-carbon architectural structures. The focus is placed on the conceptual exploration of a rich and diverse solution set rather than on the analytical sizing of a given system. Hand-controlled methods and computational tools are mixed, as well as strategies to rapidly take key decisions. The open-ended problem assignment gravitates around the use of graphic statics within Grasshopper (Rhino3D). Additional lectures review exemplary early-stage structural design processes through history.

AR-440 (UE-K) Architecture and Sustainability: Performance Studies

This course evolves around the team design of a temporary, mobile and sustainable pavilion, a pedagogical approach which will focus on the introduction of the concepts of sustainability applied to the multi-disciplinary design of a project with a short life span.

AR-497 “Building Design in the Circular Economy” is integrated in the following multidisciplinary ENAC minors:

master projects

Proposals for master theses in Architecture or Civil Engineering can be addressed to Corentin Fivet.

We are currently looking for master students to help us with specific lab projects.

2023

Piscine Tournesol – Sauvegarde et reconversion d’un objet technique et social

2021.

Logement en terre crue pour l’Ouest Lausannois

C. Dindault

2021.

Pensée globale, construction locale: stratégies d’adaptation d’une culture du bâti individualiste aux contraintes communautaires de la vie contemporaine et du développement durable

D. Bustion

2021.

Projet de coexistance territoriale entre espèce humaine et avifaune: renaturation de millieux humides et retour des oiseaux d’eau dans les espaces riverains urbains de la baie de la Chamberonne

M. Aubert

2021.

Microferme communautaire

J. Allémann

2021.

Entre terre et mer – Une communauté flottante au coeur d’Helsinki

S. Aeschimann; N. Otti

T. Beuret

2020.

À la croisée des chemins. Résidence étudiante, convergence de la vie domestique et collective

A. Marrucho Nunes

2020.

Une architecture de la promotion immobilière? Contre-projet d’un bâtiment de logements collectifs à Annemasse, France

E. Exposito

2020.

Conception d’un complexe ou une série de modules durables de logements et activités comme activateurs de durabilité d’une ville suisse

A. Genton

2020.

L’hybridation, catalyseur de mixité fonctionnelle et sociale pour le quartier de Grosselin

A. Montessuit

2020.

Logements en construction composite en bois dans la région des Apennins

A. Settimi

STRUCTURAL FORM-FINDING FROM RECLAIMED BAR ELEMENTS

J. Desruelle

2018.

ready-for-reuse building structures

We pioneer technical solutions that foster reuse loops.
Building uses evolve but construction material remains. In order to keep up with the constantly updated needs of our society, we renovate our buildings. More precisely, we replace their envelope or inner wall partitioning. And we try to keep their structural skeleton in place as long as possible. Despite modern developments in modularity, however, market requirements will sooner or later push the structural skeleton to be demolished as well and to leave room for a brand new one. But processing raw material for the construction industry has substantial environmental costs. Whereas solutions exist to design new building envelopes, finishing and equipment that allow their reuse, no robust and global solution exists to effectively reuse structural load-bearing systems after deconstruction.

Our aim is to design a highly-versatile load-bearing system for 6-story-high office buildings that can be disassembled and reassembled in new spatial configurations two to three times over a life-span of 200 years. While fulfilling certain boundary rules (maximum span, etc.), we allow the positioning of columns to be as open as possible in order to allow any unpredicted use and transformation of the building.

Full-scale prototypes have been tested. A patent request has been submitted. We will soon be delighted to publish more about it.

Sustainability through reuse: a reconfigurable structural system for residential and office buildings

A-M. Muresan; J. Brütting; D. Redaelli; C. Fivet

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 necessary oversized elements and extra connections. Through a review of building demolition cases, this paper first presents motives, challenges and requirements for overcoming adverse end-of-life environmental impacts of building structures. Then a new structural system addressing the specified design constraints is introduced. The system is a highly versatile kit of slab and column elements. Contrary to existing modular solutions, its element dimensions do neither constrain the positioning of columns nor the shape of floor plans. Slab elements are stacked vertically to tune bending and shear stiffnesses locally and ensure serviceability requirements for a wide range of column and load cases layouts. All connections between elements are reversible and ready for reuse. Accordingly, the proposed structural system is well-suited for multiple service cycles and architectural needs, mitigating the detrimental effects that buildings have on the environment.

2020-11-02. Beyond2020 – World Sustainable Built Environment, Online, November 2-4, 2020.

Design Space of Modular Slab Systems with Discrete Stiffness Distribution and Irregular Column Layout

A. Mureșan; J. Brütting; J. Cañada; D. Redaelli; C. Fivet

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 a positioning of columns satisfying serviceability requirements; and 2) for a given satisfying positioning of columns, the distribution of slab elements that minimizes the overall weight of the system. This study is part of a larger project aimed at developing a highly flexible floor system whose element dimensions do not constrain the positioning of the columns nor the shape of the floor plan. Hence, the structural system could be adapted over time to changing architectural needs.

2018-07-16. IASS Symposium 2018, MIT, Boston, Massachusetts, USA, July 16-20, 2018.

Redistribution of strength and stiffness according to new needs.

Other publications:

Design of Load-Bearing Systems for Open-Ended Downstream Reuse
SBE conference 2019 (detailed record)

waste upcycling

We prototype state-of-the-art structural applications with reclaimed waste.
The reuse of discarded components allows material to be saved from the landfill and the manufacturing of new components to be prevented. Still, reuse is only worthwhile if it reclaims the technology originally embedded in the material in the best way possible, turning a moral issue into an engineering one. This engineering issue is of a new kind: instead of detailing components from a predefined system, the system must be found from predefined components whose composition and past history is unknown. The overall stability of the new system must be ensured although inner mechanical characteristics of components remain partially unspecified.

GeoGami pavilion, Smart Living Lab, 2021.

We have designed and constructed to pavilions with reclaimed skis:

The GeoGami pavilion (summer 2021)
The ski gridshell (spring 2017)

The GeoGami pavilion (summer 2021)

The GeoGami pavilion is a blend of differential geometry, upcycling reuse, and digital fabrication. It consists in GEOdesic lines of reclaimed skis working in collaboration with a discrete Voss surface of laced timber panels, smoothly unfolded like an oriGAMI.

The pavilion is a demonstration that careful structural design and computational methods can help recover the technology embedded in waste, in unforeseen ways, hence creating new circular flows.

Due to their composite nature, skis are waste that is rarely valued, except for energy recovery through incineration. Yet, their unique mechanical behavior, i.e. good bending behavior in one direction and great stiffness in the other one, is comparable to timber laths used in conventional elastic gridshells. The form-finding process ensures that the curves of skis can be assembled from initially straight lines, that there is no torsion in the skis, that every intersecting lines of skis present a flat contact, that the edges of adjacent quad panels perfectly coincide, and that series of panels can be assembled folded, flat on the ground and fit the freeform geometry of the gridshell once unfolded.

Nicolas Montagne (design and construction lead)
Corentin Fivet, Olivier Baverel, Cyril Douthe (direction)
Maxence Grangeot, Charles Haskell, Claude-Alain Jacot, Krittika Walia (construction & pictures)
Sofia Villegas, Barbara Lambec (additional pictures)
Atelier PopUp, Smart Living Lab (facility)
Structural Xploration Lab and Laboratoire Navier, Ecole des Ponts, ParisTech) / Thinkshell (institutions)

Related publications:

Discrete Voss surfaces: Designing geodesic gridshells with planar cladding panels, Automation in Construction 2022 (detailed record)
Generation of elastic geodesic gridshells with anisotropic cross sections, International Journal of Space Structures 2021 (detailed record)
Voss Surfaces: A Design Space for Geodesic Gridshells, Journal of the International Association for Shell and Spatial Structures 2020 (detailed record)

The ski gridshell (spring 2017)

Introduced as a proof of concept, this 11*6m² elastic gridshell from 200 reclaimed skis demonstrates that the technology embedded in discarded sport equipment can perform better than conventional materials in specific high-demanding structural purposes. The pavilion has been presented at the first Architecture Biennale in Lyon, summer 2017, at the 2017 international symposium of the IASS, and is currently on display in French ski resorts.

Elastic gridshells are special structures that can be assembled without scaffolding. They gain their rigidity thanks to the permanent bending of their elements after being pre-assembled on a flat surface. Pioneered by Frei Otto and Ted Happold in Mannheim (1975), elastic gridshells have since been then commonly built with small, high-strength timber laths.

Sometimes, reclaimed material from other sectors are good alternatives to conventional material. Skis, as many other high-end sport equipment, have a very short lifespan and cannot be cheaply recycled because of their composite nature. However, even after years of second-hand cycles, skis maintain valuable mechanical properties: high curvature capacity in one direction and great rigidity in the transverse direction.

On the one hand, skis greatly vary in stiffness. On the other hand, the geometric stiffness of the shell is not uniform. Part of the designer’s role is therefore to assign the diverse skis at the most appropriate locations on the gridshell, in order to ensure overall stability and minimize deflections.

Corentin Fivet (project investigator)
Sofia Colabella (gridshell designer & worksite manager)
Bernardino D’Amico (form-finding)
Claude-Alain Jacot (procurement & construction)
Jan Brütting (detailing & construction)
Valeria Didonna, Jacopo Orlandi, Julieta Moradei (construction)
Endrit Hoxha (life-cycle analysis)

Structural Design with Reclaimed Materials: an Elastic Gridshell out of Skis

S. Colabella; B. D’Amico; E. Hoxha; C. Fivet

This paper presents the design and construction of a 36m2 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 multiple times without scaffolding and by means of traditional tools only. After a brief introduction on the need for reducing embodied carbon and waste in structures through reuse, the paper sets up the constraints that have driven the definition of the pavilion, the main one being the extension of the lifetime of high-performance sport equipment by reclaiming their intrinsic mechanical properties. The paper then details the encountered unusual aspects in the design process and how they have been overcome – i.e. sporadic material supply, categorization of mechanical properties, physical alteration of these properties, and uncertainties in the numerical modelling of both the structural analysis and the construction process. Eventually, we conclude that reclaimed skis as a material have the potential to be as good as conventional timber when designing elastic gridshells. A series of future directions for this emerging field of research are also laid out.

2017. IASS Annual Symposium 2017 “Interfaces: architecture.engineering.science”, Hamburg, Germany, September 25-28, 2017.

Variation of bending stiffness in all reclaimed skis

Ski sorting along the arch, as a consequence of the geometry stiffness of the gridshell, bracing system, and ski assembly detail.

Other publications:

EPFL Mediacom (video and news)
Experimental investigation of beams under coupled bending and torsion
IASS conference 2019 (detailed record)

applications of graphic statics

We showcase exemplary practices of graphical explorations of equilibrium shapes.
Developed during the second-half of the 19th Century, graphic statics quickly became a method of choice for analyzing stresses inside truss systems. Today, this structural analysis process is better achieved with faster and more comprehensive numerical methods. However, graphic statics remains a tool of choice for early-stage structural design, i.e. when the geometry of the system is not decided yet and is to be explored simultaneously with the load-paths related to it. Moreover, the range of applications of graphic statics has expanded beyond planar trusses and the automation of graphic statics procedures is now easily implemented into computational parametric environments. The application of graphic statics to early-stage design explorations has never been as relevant as today.

Robert Maillart’s Key Methods From the Salginatobel Bridge Design Process (1928)

This paper sheds light on some of the graphical methods used by Robert Maillart to design the Salginatobel Bridge, a three-hinged concrete structure spanning 90 meters. Built in 1929, this masterpiece has since received extensive recognition both for its structural elegance and its efficiency. However investigations into the design process enabling this degree of perfection remain incomplete. Studying Maillart’s original working drawings, this paper reviews the earliest stages chronology of the Salginatobel Bridge design process. It focuses on three methods: the use of graphically controlled parabolas, the minimization of bending moments within the bridge and the geometrical definition of the foundation block. These graphical methods reveal how Maillart simultaneously dealt with geometry and the flow of forces throughout using a straightforward, handy and efficient form-finding process which is still relevant today.

Journal of the International Association for shell and Spatial Structures. 2012. Vol. 53, num. 1, p. 39-47.

The Graphic Statics behind the Collier Memorial

C. Fivet; J. Ochsendorf

This paper reviews the various graphic statics methods applied during the early structural design of the Collier Memorial, Cambridge, MA. Built in 2015 to honor fallen MIT Police Officer Sean Collier, the monument is a vaulted assembly of massive granite blocks. They are held together with pure compression contact when under the action of gravity alone. This non-conventional structural typology has only rare contemporary precedents and its design consequently innovates in various areas. In particular, assumptions of plastic theory and graphic statics have been combined to explore the design space, to assess stability, to study collapse mechanisms and to provide factors of safety related to maximum allowed displacements and maximum allowed live load. These methods proved to be a faster and sounder alternative to conventional discrete-element methods during the conceptual design stage.

2018-07-16. IASS Symposium 2018, MIT, Boston, Massachusetts, USA, July 16-20, 2018.

Design and exploration of externally post-tensioned structures using graphic statics

L. Todisco; C. Fivet; H. Corres Peiretti; C. Mueller

Funicular structures, which follow the shapes of hanging chains, work in pure tension (cables) or pure compression (arches), and offer a materially efficient solution compared to structures that work through bending action. However, the set of geometries that are funicular under common loading conditions is limited. Non-structural design criteria, such as function, program, and aesthetics, often prohibit the selection of purely funicular shapes, resulting in large bending moments and excess material usage. In response to this issue, this paper explores the use of a new design approach that converts non-funicular planar curves into funicular shapes without changing the geometry; instead, funicularity is achieved through the introduction of new loads using external post-tensioning. The methodology is based on graphic statics, and is generalized for any two-dimensional shape. The problem is indeterminate, meaning that a large range of allowable solutions is possible for one initial geometry. Each solution within this range results in different internal force distributions and horizontal reactions. The method has been implemented in an interactive parametric design environment, empowering fast exploration of diverse axial-only solutions. In addition to presenting the approach and tool, this paper provides a series of case studies and numerical comparisons between new post-tensioned structures and classical bending solutions, demonstrating that significant material can be saved without compromising on geometrical requirements

Journal of the International Association for shell and Spatial Structures. 2015. Vol. 56, num. 4, p. 249-258.

I. Mirtsopoulos; C. Fivet

other related publications:

Guastavino design of the 1909 thin brick dome of the Cathedral of St John the Divine
CHS journal 2017 (detailed record)
Graphic statics and interactive optimization for engineering education
Structures Congress 2015 (detailed record)
Graphical methods for the design of Catalan vaults: the case of Luis Moya Blanco’s Nuestra Señora de la Araucana in Madrid
ICSA conference 2016 (detailed record)
What Maurice Koechlin’s scientific contribution tells about his life (1856-1946)
ICCH conference 2015 (detailed record)
An Optimized Bracing System for Distributed Lateral Loads
ACE conference 2016 (detailed record)
数字化图解静力学设计方法 — 建筑师和结构工程师共享的设计工具 (Digital Graphic Statics – Shared Design Tools for Architects and Engineers)
Architecture Journal 2017 (detailed record)

generative grammars

We unlock the interactive exploration of structural equilibrium shapes.
Design is an ill-structured and costly problem whose complexity can significantly increase during the process due to emerging requirements. How can the computer help the designer during the early-stage design of structures? How should they communicate together? How can the machine provide instant feedback on performance requirements, allow for fast generative exploration of alternative solutions and be capable of unveiling unexpected structural typologies?

Design space exploration through force-based grammar rule

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 have shown their great potential to explore design in a fast way. However, the digitalization of the process is not sufficient to ensure the generation of radically new designs and subsequently not guaranteed to explore the full range of the design space. The design of architectural forms, that are structurally relevant, shares the same challenges and risks. Additionally, it introduces equilibrium constraints.This paper presents a design framework, which fuses force-driven grammar rules for the generation of unprecedent spatial structural systems that go beyond any existing catalogues of mathematically known structural typologies. Operating on a rule-based level rather than on a variable-based level, allows the incremental transformation of the model and the backtracking to previous steps, while static equilibrium is always retained. The acquired transformations are possible to be slightly or highly constrained along with the designer’s intended exploration preferences.

archiDOCT. 2020-07-01. Vol. 8, num. 1, p. 50-64.

I. Mirtsopoulos; C. Fivet

Grammar-based generation of trusses within non-convex domains

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 always leads to complete networks but ensures static equilibrium throughout the process. Overall, it operates as a form-finding engine for planar trusses and helps designers to gain knowledge and develop intuition about structural design. A number of case studies highlight the factors that affect: the number of iterations, the exploratory power, as well as the additional parameters that are required to apply a rule. Extension of the method to more general applications is eventually suggested.

2019-09-27. International fib Symposium on Conceptual Design of Structures, Madrid, Spain, September 26-27, 2019. p. 193-200.

Alternative designs resulting from an increasing number of initial diverging rules (from top to bottom) and from a various set of positions for each new point P (from left to right).

Automatic generation of diverse equilibrium structures through shape grammars and graphic statics

J. Lee; C. Mueller; C. Fivet

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 structures; (2) exploration of various design alternatives without any biases toward pre-existing typologies; (3) customization of the framework for unique formulations of design problems and a wide range of applications; and (4) intuitive, bidirectional interaction between the form and forces of the structure through reciprocal diagrams. Design tests presented in this article illustrate the creative potential of the proposed approach and demonstrate the possibility for unbiased explorations of richer and broader design spaces during early stages of design, with much more trial and less error.

International Journal of Space Structures. 2016. Vol. 31, num. 2-4, p. 146-163. DOI : 10.1177/0266351116660798.

other publications:

Modelling with forces: grammar-based graphic statics for diverse architectural structures
Design Modelling Symposium 2015 (detailed record)
Grammar-based generation of equilibrium structures through graphic statics
IASS Symposium 2015 (detailed record)

extensions of graphic statics

We bring reciprocal diagrams to the 21th Century.
Methods of graphic statics were created in the 19th Century, at a time when the pencil and the piece of paper were the common medium. Combined with contemporary graphical capabilities of computers, graphic statics gain new relevance for early-stage structural design. Rather than assuming that modern graphic statics are just a computerized version of classical graphic statics, the old methods leading to the construction of graphic statics diagrams should be reinvented in order for designers to benefit the most from the new digital medium.

Vector-Based 3D Graphic Statics: a framework for the design of spatial structures based on the relation between form and forces

P. D’acunto; J-P. Jasienski; P. O. Ohlbrock; C. Fivet; J. Schwartz et al.

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 process. Several procedures for the construction of a vector-based 3D force diagram for any given 3D form diagram with an underlying planar or non-planar graph are identified and described. In the non-planar case, the proposed procedures rely on the preliminary topological planarization of the graph by cutting the crossing edges and reconnecting them to one or more newly inserted auxiliary vertices. The resulting planar graph can be then used as a base for the assembly of the 3D force diagram, without altering the static equilibrium of the structure. An implementation of the proposed framework to real design scenarios is presented through two case studies. These examples show how to take advantage of the bi-directional manipulation of the diagrams in the structural design process.

International Journal of Solids and Structures. 2019-02-18. Vol. 167, p. 58-70. DOI : 10.1016/j.ijsolstr.2019.02.008.

Projective transformations of structural equilibrium

C. Fivet

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 transformations that maintain static equilibrium have not been studied in detail. The contributions of this article are as follows. First, an extensive review of transformation methods maintaining static equilibrium of planar and spatial structures is carried out. Second, an alternative construction of projective transformation is developed as an original set of graphical operations. Third, the benefits and limitations of use of projective transformations are discussed for the first time. This article concludes that (1) projective transformations are of practical interest only for a restricted range of structural applications but (2) can significantly simplify the computational problem of geometric exploration of spatial networks in equilibrium with few or no external forces.

International Journal of Space STructures. 2016. Vol. 31, num. 2-4, p. 135-146. DOI : 10.1177/0266351116660796.

Graphical construction of parametric projective transformation.

A fully geometric approach for interactive constraint-based structural equilibrium design

This paper introduces computational techniques to support architects and structural designers in the shaping of strut-and-tie networks in static equilibrium. Taking full advantage of geometry, these techniques build on the reciprocal diagrams of graphic statics and enhance the interactive handling of them with two devices: (1) nodes — considered as the only variables — are constrained within Boolean combinations of graphic regions, and (2) the user modifies the diagrams by means of successive operations whose geometric properties do not at any time jeopardize the static equilibrium. This constructive approach enables useful design-oriented capabilities: a graphical control of multiple solutions, the direct switching of the dependencies hierarchy, the execution of dynamic conditional statements using static constraints, the computation of interdependencies, and coordinate-free methods for ensuring consistency between certain continuums of solutions. The paper describes a computer implementation of these capabilities.

Computer-Aided Design. 2015. Vol. 61, p. 42-57. DOI : 10.1016/j.cad.2014.04.001.