Bechert, S., Aicher, S., Gorokhova, L., Balangé, L., Göbel, M., Schwieger, V., Menges, A., & Knippers, J. (2025). Segmented Timber Shells for Circular Construction: Relocation, Structural Assessment, and Robotic Fabrication of a Modular, Lightweight Timber Structure.
Buildings,
15, Article 11.
https://doi.org/10.3390/buildings15111857 Abstract
Segmented timber shells present a novel building system that utilizes modular, planar building components to create lightweight free-form structures in architecture. Recent advancements in the research field of segmented timber shells pursue, among others, two fundamentally opposing research objectives. 1. The modularity of their building components facilitates the reuse of such structures in response to a changing built environment. 2. Advanced developments aim at establishing segmented timber shells as permanent building structures for sustainable architecture. This paper addresses the first research objective through the successful relocation of the BUGA Wood Pavilion in the context of the proposed methodology of Co-Design for circular construction. The methods and results involve integrative design and engineering processes and advanced quality assessment methods, including structural, geodetic, and physical properties for modular timber constructions. The BUGA Wood Pavilion serves as a building demonstrator for the presented research on segmented shells as lightweight, reusable, and durable timber structures. Siriwardena, L., Stark, T., Lut, S., Wagner, H. J., Maierhofer, M., Bechert, S., Knippers, J., & Menges, A. (2024). Joint Effort - A Material-Robot System for Fibrous Joints of Lightweight Timber Construction. In M. Wessely, V. Savage, P. Didyk, & J. Martinez (eds.),
Proceedings of the 9th ACM Symposium on Computational Fabrication (pp. 5, 1–20). Association for Computing Machinery.
https://doi.org/10.1145/3639473.3665791 Abstract
In response to the escalating demands of global urbanisation and the environmental imperative to minimise material usage and emissions, this research proposes an autonomous material-robot system to assist in a potential solution for timber building extension. The system demonstrates multi-robot in-situ joining strategies by co-designing a structural joint with a timber building system and mobile robotic agents. In-situ robotic joining techniques are essential for a fully autonomous on-site assembly workflow, but they largely remain unexplored. The investigation focuses on developing a mobile joining robot that locomotes pre-routed grooves while deploying carbon fibre-reinforced polymers (CFRPs), establishing a structurally performant wood joint in-situ. In contrast to current human-centric steel fasteners, CFRPs are flexible and compact and can be easily integrated into mobile robots, enabling the exploration of novel robot-oriented connection typologies. By understanding the timber as an integral part of the robotic system, assembly information, including instructions for navigation, tasks and localisation, is pre-programmed into the material. This substantially reduces robot complexity, weight, size, and cost and allows for decentralised control of the connection agents. The robot path becomes the structural joint path. A fully autonomous assembly choreography can be performed on-site through cooperation between different robots and materials. This leverages the task-specific capabilities of each agent in the team and high-accuracy prefabrication. The introduction of this system proposes a shift away from traditional human-centric construction methods towards a robot-oriented building strategy. This approach challenges the conventional reliance on steel fasteners in timber assemblies and demonstrates the potential for robotic teams to facilitate sustainable and innovative construction methodologies. The research expands on fibrous joints by automating them and furthering Collective Robotic Construction (CRC) research by integrating novel structural fastening methods. Di Bari, R., Lauer, A. P. R., Schlopschnat, C., Treml, S., Opgenorth, N., Skoury, L., Stark, T., Bechert, S., Göbel, M., Wagner, H. J., Wood, D., Leistner, P., Knippers, J., Menges, A., Sawodny, O., & Wortmann, T. (2024).
Computational design and robotic fabrication for high environmental quality timber constructions: the livMatS Biomimetic Shell case study [DaRUS].
https://doi.org/10.18419/darus-4434 Abstract
The dataset includes the raw data and the corresponding report for the life cycle assessment of the building demonstrator 'livMatS Biomimetic Shell' (Website).The pressure on the construction industry to reduce its environmental impact is leading practitioners to investigate the use of more sustainable materials, such as timber. Still, due to its limited availability, it is questioned to which degree timber could substitute steel and concrete, and strategies to reduce its consumption are necessary. The Cluster of Excellence “IntCDC” investigates novel approachesto sustainable architecture. These exploit integrative computational design and automatic fabrication. These have been showcased in the livMatS Biomimetic Shell, for which a hollow timber cassette has been realized. In this study, the Lifecycle Assessment (LCA) analysis evaluated the developed cassette's environmental profile compared with other functionally equivalent systems. The analyses showed that the livMatS Biomimetic Shell reduced material consumption by 51% and a Global Warming Potential (GWP) 39% lower than conventional timber construction. Optimized fabrication processes allowed for emissions reduction by 60% in comparison with a solid cross-laminated timber box. Orozco, L., Krtschil, A., Wagner, H. J., Bechert, S., Amtsberg, F., Knippers, J., & Menges, A. (2023). Co-Design Methods for Non-Standard Multi-Storey Timber Buildings.
Sustainability,
15, Article 23.
https://doi.org/10.3390/su152316178 Abstract
To meet climate change goals and respond to increased global urbanisation, the building industry needs to improve both its building technology and its design methods. Constrained urban environments and building stock extensions are challenges for standard timber construction. Co-design promises to better integrate disciplines and processes, promising smaller feedback loops for design iteration and building verification. This article describes the integrated design, fabrication, and construction processes of a timber building prototype as a case study for the application of co-design methods. Emphasis is placed on the development of design and engineering methods, fabrication and construction processes, and materials and building systems. The development of the building prototype builds on previous research in robotic fabrication (including prefabrication, task distribution, and augmented reality integration), agent-based modelling (ABM) for the design and optimisation of structural components, and the systematisation of timber buildings and their components. The results presented in this article include a functional example of co-design from which best practises may be extrapolated as part of an inductive approach to design research. The prototype, with its co-designed process and resultant flat ceilings, integrated services, wide spans, and design adaptability for irregular column locations, has the potential to expand the design potential of multi-storey timber buildings. Shah, A., Sahin, E. S., Malafey, A., Bechert, S., Maierhofer, M., Knippers, J., & Menges, A. (2022). Assembly-Oriented Design Methodology for Segmented Timber Shells. In S.-d. Xue, J.-z. Wu, & G.-j. Sun (eds.), Innovation, Sustainability, Legacy: Proceedings of the IASS 2022 Symposium affiliated with APCS 2022 conference (pp. 1526–1537).
Abstract
This research demonstrates a structurally-informed assembly method for the construction process of modular timber structures. Within the context of modular timber structures, segmented timber shells are of great interest for large span applications. These structures predominantly confront external loads through membrane action and therefore have reduced bending moments. During erection of these structures, assembly stages with unfavourable spanning conditions and high bending moments occur. In traditional construction methods, scaffolding is built below the shell structure to stabilize the assembly steps. This temporary reinforcement results in uneconomical, time-consuming and labour-intensive construction. Moreover, they create a congested working space which sometimes results in unsafe working conditions for laborers. The research proposes a design method which reimagines the reciprocity between the design, the on-site robotics and the coordination of the on-site equipment as a structurally-informed design for assembly methodology for segmented timber shell structures. It brings the possibility of supportless assembly and automated erection, while opening up unexplored design possibilities for segmented timber shells. Krtschil, A., Orozco, L., Bechert, S., Wagner, H. J., Amtsberg, F., Chen, T.-Y., Shah, A., Menges, A., & Knippers, J. (2022). Structural development of a novel punctually supported timber building system for multi-storey construction.
Journal of Building Engineering,
58, 104972.
https://doi.org/10.1016/j.jobe.2022.104972 Abstract
Though capable of allowing multi-directional spans, timber products such as cross-laminated timber are primarily utilized uni-directionally using linear supports like walls or beam elements. Recent building designs increasingly show punctual supports but with narrow column grid layouts. Support beams and narrow grids limit the design space for multi-storey timber buildings. To overcome these design limits, an integrative design concept for punctually supported timber slabs is being developed that allows for large spans and irregular column layouts. Therefore, engineering methods are integrated in the architectural design of the building components, such as plates, columns, and their connections. The developed slab system combines hardwood and softwood materials in a sandwich construction. The plates have a tailored internal topology considering the force flow in the slab. A plate-to-plate connection design is evaluated through mechanical tests, which also serve as calibration for the global structural model. The research findings are validated through the design and construction of a large scale demonstrator: the ITECH Campus Lab. Bechert, S., Aldinger, L., Wood, D., Knippers, J., & Menges, A. (2021). Urbach Tower: Integrative structural design of a lightweight structure made of self-shaped curved cross-laminated timber.
Structures,
33, 3667–3681.
https://doi.org/10.1016/j.istruc.2021.06.073 Abstract
Recent development in research and practice for curved cross-laminated timber (CLT) opens up novel and interesting possibilities for applications of slender surface-active shell structures in architecture. Such typologies provide advantageous structural behaviour allowing for efficient and lightweight structures while simultaneously determine the envelope and space of a building. The high degree of prefabrication combined with a sustainable and renewable building material makes CLT an ecological and economic solution for future construction. This paper presents the design development and construction of the Urbach Tower for the Remstal Gartenschau 2019: a structure made from high curvature CLT components on a building scale. This research contribution illustrates a sophisticated integrative design to construction process emphasizing computational and structural design, fabrication and detailing for curved timber components in complex spatial structures. The authors further explore the structural potential of self-shaped curved CLT investigating the influence of curvature radius on the load-bearing behaviour of the tower structure. The Urbach Tower translates these technical developments into practice arising at the intersection of digital innovation and scientific research. Orozco, L., Krtschil, A., Wagner, H. J., Bechert, S., Amtsberg, F., Skoury, L., Knippers, J., & Menges, A. (2021). Design Methods for Variable Density, Multi-Directional Composite Timber Slab Systems for Multi-Storey. In V. Stojakovic & B. Tepavcevic (eds.),
Proceedings of the 39th eCAADe Conference (Vol. 1, pp. 303–312). Cumincad.
http://papers.cumincad.org/cgi-bin/works/paper/ecaade2021_284 Abstract
This paper presents an agent-based method for the design of complex timber structures. This method features a multi-level agent simulation, that relies on a feedback loop between agent systems and structural simulations that update the agent environment. Such an approach can usefully be applied for the design of variable density timber slab systems, where material arrangements based on structural, fabrication, and architectural boundary conditions are necessary. Such arrangements can lead to multi-directional spanning slabs that can accept pointwise supports in unique layouts. We discuss the implementation of such a method on the basis of the structural design of a pavilion-scale multi-storey testing setup. The presented method enables a more versatile approach to the design of multi-storey timber buildings, which should increase their applicability to a diverse range of building typologies. Bechert, S., Sonntag, D., Aldinger, L., & Knippers, J. (2021). Integrative structural design and engineering methods for segmented timber shells : BUGA Wood Pavilion.
Structures,
34, Article December.
https://doi.org/10.1016/j.istruc.2021.10.032 Abstract
The presented research describes the holistic development of a modular lightweight timber shell. So-called segmented timber shells approximate curved geometries with the use of planar plates, thus combining the excellent structural performance of double curved shells with the resource-efficient prefabrication of timber modules using only planar elements. Segmented timber shells constitute a novel building system that demands for innovative approaches on structural design and construction technologies. The geometric complexity of plate shells in conjunction with the particularities of the building material wood pose great challenges to the computational design and planning processes as structural requirements and fabrication constraints determine the shell design at early design phases. This paper discusses the design development and construction of the BUGA Wood Pavilion: A segmented timber shell structure made of hollow cassette components. Particular emphasis lies on the technical challenges of the employed building system, notably structural design and analysis, detailing solutions and the construction process. The authors further describe the integrative structural design and optimization methods developed for the timber shell in question. The BUGA Wood Pavilion demonstrates the possibilities of lightweight and sustainable wood architecture merging the merits of integrative design, structural engineering and high-tech robotic fabrication methods. Wood, D., Grönquist, P., Bechert, S., Aldinger, L., Riggenbach, D., Lehmann, K., Rüggeberg, M., Burgert, I., Knippers, J., & Menges, A. (2020). From Machine Control to Material Programming Self-Shaping Wood Manufacturing of a High Performance Curved CLT Structure - Urbach Tower. In
Making Resilent Architecture - FABRICATE 2020 (Vol. 4).
https://www.uclpress.co.uk/products/154646 Bechert, S., Sonntag, D., Aldinger, L., & Knippers, J. (2020). Statische Modellierung und Berechnung von Segmentschalen aus Holz. In B. Oesterle, M. Bischoff, & m. Von Scheven (eds.), Baustatik - Baupraxis 14 (Vol. 14, pp. 407–414).
Christie, J., Solly, J. J., Bechert, S., & Knippers, J. (2019). Bending-driven Dynamic Corrugation for a Funnel Shell Design. In C. Lázaro, K.-U. Bletzinger, & E. Oñate (eds.), Proceedings of the IASS Annual Symposium 2019 – Structural Membranes 2019 (pp. 2627–2634).
Abstract
Funicular shells are known to be an efficient design paradigm for self-weight-driven structural surfaces 1. Nevertheless, the rules that govern funicularity offer a fairly constrained design spectrum, limiting the scope of application for these structures 2. The principle of corrugation has proven to be an effective approach to enable efficient structural performance in non-funicular thin shells 3. The research presented in this paper explores the use of corrugation methods for shells in the context of a computational and structural design workflow. As an extension to existing methods, the authors introduce work on Dynamic Corrugation, a strategy for increasing bending and buckling performance on non-funicular global designs by modulating the undulation of their surfaces according to bending stress distribution. The bending-driven dynamic corrugation method was developed during the Form and Structure seminar of the ITECH programme at the University of Stuttgart and was evaluated through the design of a non-funicular funnel shell in textile concrete. The method consists of a two-step Shape Optimization workflow that integrates NURBS-based surface generation with FEA and a Multi-Objective Genetic Algorithm (MOGA). In a first step of the design workflow, the initial design surface is analyzed to give its bending energy vector field. This field then serves as the source to generate a modulation curve passing through the areas of peak bending stresses. This curve then regulates the frequency, amplitude, and influence of local bending on the corrugation. The MOGA is given control over these variables and attempts to minimize both bending moment and displacements, offering a wide spectrum of performances and expressions along the emerging Pareto front. Simultaneously, the introduction of local curvature is evaluated on its capacity to improve the buckling resistance and to allow reductions in material thickness. The presented iterative approach is incorporated in a computational design framework. A series of Dynamic Corrugation-optimized shell samples are then compared with the initial non-corrugated design showing great structural (improved bending and buckling resistance), as well as economical and ecological (material savings) potential. Further, the expressive value of dynamically corrugated shells is deemed as a contribution to the aesthetic value of a design proposal for a small infrastructural building. Lotte Aldinger, Bechert, S., Wood, D., Knippers, J., & Menges, A. (2019). Design and Structural Modelling of Surface-Active Timber Structures Made from Curved CLT - Urbach Tower, Remstal Gartenschau 2019. In C. Gengnagel, O. Baverel, J. Burry, M. Ramsgaard Thomsen, & S. Weinzierl (Eds.),
Impact: Design With All Senses (Vol. 30, pp. 419–432). Springer Nature.
https://doi.org/10.1007/978-3-030-29829-633 Sonntag, D., Aldinger, L., Bechert, S., Alvarez, M., Groenewolt, A., Krieg, O.-D., Wagner, H. J., Knippers, J., & Menges, A. (2019). Lightweight segmented timber shell for the Bundesgartenschau 2019 in Heilbronn. Form and Force: Proceedings of the International Association for Spactial Structures Annual Symposia 2019 Barcelona, Article October.
Abstract
Segmented timber shells offer the possibility of constructing long span, double curved shell structures efficiently and economically. This was demonstrated with the Landesgartenschau Exhibition Hall 2014 in Schwäbisch Gmünd 1, a prefabricated segmented timber shell made of planar beech plywood plates. However, the application of this construction method for larger spans and more general shell geometries requires further technical development of the construction system, of its associated fabrication methods, and of the methods for form finding and optimisation. This paper presents the development and construction of the wood pavilion for the Bundesgartenschau (Federal garden exhibition, BUGA) 2019 in Heilbronn, which translates these technical developments into practice. Solid timber panels were replaced by a recently developed multi-layer cassette system. The 376 geometrically unique elements of the multi-layer segmented shell were produced of spruce laminated veneer lumber plates, which were assembled, glued, and milled in a fully automated process by two collaborative industrial robots. The shell segments are connected using a combination of the previously established CNC-milled finger-joints 2 as well as regularly spaced steel bolts. Custom design and analysis tools were developed, in order to manage varying material thicknesses, spacing of fasteners and geometric details of the connections between adjacent segments. Alvarez, M., Wagner, H. J., Groenewolt, A., Krieg, O. D., Sonntag, D., Bechert, S., Aldinger, L., Menges, A., & Knippers, J. (2019). The BUGA Wood Pavilion - Integrative interdisciplinary advancements of digital timber architecture. Ubiquity and Autonomy - 39th ACADIA Conference 2019, 490–499.
Abstract
Platforms that integrate developments from multiple disciplines are becoming increasingly relevant as the complexity of different technologies increases day by day. In this context, this paper describes an integrative approach for the development of architectural projects. It portrays the benefits of applying such approach by describing its implementation throughout the development and execution of a building demonstrator. Through increasing the agility and extending the scope of existing computational tools, multiple collaborators were empowered to generate innovative solutions across the different phases of the project´s cycle. For this purpose, novel solutions for planar segmented wood shells are showcased at different levels. First, it is demonstrated how the application of a sophisticated hollow-cassette building system allowed the optimization of material use, production time and mounting logistics due to the modulation of the parameters of each construction element. Second, the paper discusses how the articulation of that complexity was crucial when negotiating between multiple professions, interacting with different contractors and complying with the corresponding norms. Finally, the innovative architectural features of the resulting building are described, and the accomplishments are benchmarked through comparison with typological predecessor. Bechert, S., Groenewolt, A., Krieg, O. D., Menges, A., & Knippers, J. (2018). Structural Performance of Construction Systems for Segmented Timber Shell Structures. Proceedings of the IASS Annual Symposium 2018 Creativity in Structural Design.
Garufi, D., Wagner, H. J., Schwinn, T., Wood, D., Bechert, S., Menges, A., & Knippers, J. (2018, September). Fibrous Joints for Lightweight Segmented Timber Shells. RCA Conference 2018.
Krieg, O. D., Bechert, S., Groenewolt, A., Horn, R., Knippers, J., & Menges, A. (2018). Affordances of Complexity: Evaluation of a Robotic Production Process for Segmented Timber Shell Structures. WCTE, Proceedings of the 2018 World Conference on Timber Engineering, 1–8.
Sonntag, D., Bechert, S., & Knippers, J. (2017). Biomimetic timber shells made of bending-active segments. International Journal of Space Structures, Vol. 32, Article 3–4.
Abstract
In the research field of segmented timber shells, two construction systems have lately received much attention, which both expose interesting structural and constructional characteristics: planar plate structures made of thin plywood and actively bent plywood structures. The research presented in this article combines elements of both approaches, resulting in a construction system for segmented shell structures with elastically bent elements. The increasing complexity of this approach requires a sophisticated design process, which integrates fabrication constraints as well as structural feedback. As a consequence, form-finding strategies of bending-active timber shells are discussed, with a special focus on the programming of the stiffness distribution in order to fulfil geometrical requirements. The authors also reflect on the specific structural challenges of joining thin sheets of plywood by transferring traditional textile connection methods to timber construction. Investigations of biological role models such as the sand dollar led to transfers of constructional principles on different levels. The resulting construction system was validated through the design and construction of a full-scale architectural prototype Bechert, S., Knippers, J., Krieg, O. D., Menges, A., Schwinn, T., & Sonntag, D. (2016). Textile Fabrication Techniques for Timber Shells: Elastic Bending of Custom-Laminated Veneer for Segmented Shell. In S. Adriaenssens, F. Gramazio, M. Kohler, A. Menges, & M. Pauly (eds.), Advances in Architectural Geometry 2016 (pp. 164–169). ETH Zurich.
Abstract
Recent developments in the field of segmented timber shells have shown promising structural and constructional characteristics. Advancements in computational design and digital fabrication enable architects and engineers to handle the increased geometric complexity necessary for this new construction type, integrating fabrication constraints and structural feedback in one design model. The research presented in this paper builds on new findings from biological role models for the constructional morphology, connection type, and material distribution of segmented shells. Based on the transfer of these principles, a robotic fabrication technique was developed that enables the production of elastically bent, double-layered segments made from custom-laminated beech plywood, by transferring traditional textile connection methods to timber construction. The construction system was evaluated through the design, production, and assembly of a large demonstrator.
