Tzu-Ying Chen

Abstract

This paper presents the co-design methods for a new hybrid load-bearing system as a strategy for advancing bio-based architecture. Timber and natural fiber polymer composites (NFPC) are combined into a hybrid system, offering opportunities to leverage their strengths while balancing the use of natural resources. The system performs synergistically, with each material fulfilling complementary roles. Timber extrapolates its structural function by acting as an embedded frame for the fibers to be wound on. The paper presents computational methods designed to optimize material performance while integrating functionalities and fabrication opportunities. A dual-robot winding method is presented as a solution for balancing winding tension in the structure during fabrication. The hybrid system is demonstrated through the design and construction of a pavilion, the first to combine flax fibers with a partially bio-based resin and timber into a dual-robotically fabricated structure on an architectural scale. The project represents further advancements in multi-robot fabrication and a novel material approach toward bio-based hybrid systems in architecture.

Abstract

Der Hybrid-Flachs Pavillon der Landesgartenschau 2024 in Wangen im Allgäu dient als Demonstrator für die Entwicklung, Herstellung und Verwendung neuartiger, robotisch gefertigter Naturfaserelemente auf Basis von Flachsfasern in einer Gebäudestruktur. Ziel war es, ein leichtes, ressourceneffizientes und zugleich leistungsfähiges Konstruktionssystem auf Basis von Naturfasern für lastabtragende Bauteile zu demonstrieren. Die verwendeten Naturfasern wurden lokal bezogen und im Wickelverfahren mit Epoxidharz zu komplexen Tragstrukturen verarbeitet. Durch die Kombination aus experimentellen Untersuchungen im Maßstab 1:1 und numerischer Modellierung wurde ein Verfahren zum Nachweis der Tragfähigkeit entwickelt, das die Geometrie, die Materialeigenschaften sowie die Bedingungen der Herstellung berücksichtigt. Großversuche lieferten wesentliche Erkenntnisse zu Steifigkeit, Bruchlast und Versagensmechanismen, insbesondere zum Faserabriss an den Bolzenverankerungen. Auf dieser Grundlage wurden detaillierte FE-Modelle erstellt und zu vereinfachten Hybridmodellen weiterentwickelt, um eine realitätsnahe Abbildung der Tragwirkung in einem statischen Gesamtmodell des Pavillons zu ermöglichen.

Abstract

The construction industry significantly contributes to global carbon emissions and resource depletion, necessitating a transition toward more sustainable materials. Renewable materials show high potential as an alternative to conventional fossil-based materials in mitigating climate change within the construction industry. Diversifying the sourcing, especially for plant-based materials, is imperative to ensure sustainability and prevent overreliance on specific resources. In prior studies, Coreless Filament Wound (CFW) natural fiber-reinforced polymer (NFRP) systems have demonstrated promising material efficiency and structural performance. However, the lack of research on their long-term performance in construction applications presents a significant barrier to widespread market adoption. This study addresses this gap by designing, developing, and evaluating the Hybrid Fibre Pavilion constructed for the 2024 Landesgartenschau in Wangen im Allgäu. The pavilion incorporates simply supported beams fabricated from robotically wound NFRPs and cross-laminated timber (CLT) slabs. Full-scale structural components were robotically manufactured and subjected to distributed ultimate load, creep, and cyclic load tests. The findings highlight the viability of this hybrid structural system, demonstrating its potential for robust instantaneous and long-term performance in construction.

Abstract

Wood is a renewable, carbon-sequestering material, but its efficient use is critical for sustainable forestry and avoiding land use conflicts. Integrating flax fiber composites with wood enables material-efficient construction by combining the strengths of both materials. While flax offers a sustainable alternative to synthetic fibers, its cultivation in Germany is still limited, and bio-based hybrids face regulatory and certification challenges. The Hybrid Flax Pavilion showcases an innovative flax fiber–timber system, reducing timber use through thin cross-laminated timber combined with fast-renewing flax fibers. Its load-bearing structure was assembled in only eight days using minimally invasive methods and prefabricated, digitally manufactured building components. By collaborating with local craftspeople and industry partners, the project strengthens the bioeconomy and promotes responsible use of bio-based materials. It sets a precedent for circular, low-carbon architecture by integrating regional resources, digital fabrication, and research-driven practice.

Abstract

The growing demand for inhabitable spaces drives increased reliance on energy-intensive construction materials such as concrete and steel, which significantly contribute to global carbon emissions and resource depletion, highlighting the urgent need for sustainable alternatives. Renewable, bio-based materials like timber provide viable solutions, offering carbon sequestration and reduced environmental impact but lead to challenges related to biodiversity conservation, land use, and sustainable forest management. Natural fibers such as flax are increasingly used in sustainable composite materials and exhibit short growth cycles, minimal environmental impact, and favorable mechanical properties. When combined with timber, natural fiber-timber hybrids offer a large potential for high-performance, resource-efficient structural building parts. By leveraging the complementary strengths of both materials, such hybrids reduce reliance on valuable timber resources, replacing them with fast-growing flax fibers. To realize this potential for natural fiber-timber hybrid beam elements, existing design, evaluation, and fabrication methods for fibrous building parts are expanded and adapted. Suitable material candidates for fiber-timber hybrids are classified and characterized, and morphological parameters are defined to design and evaluate novel beam typologies. To allow for the manufacturing of large-scale natural fiber bodies for use in hybrid beam elements, new robotic fabrication methods are introduced, and existing manufacturing equipment is expanded. These innovations are exemplified by the Hybrid Flax Pavilion, the first permanent building to incorporate load-bearing natural fiber-timber hybrid components.

Abstract

his paper presents a novel design-to-assembly method that enables resource-efficient branching timber structures. We introduce a bio-based material system that employs anisotropy-driven design and fabrication strategies alongside a computational design tool for structurally-informed design explorations. Particular attention is directed to connec-tions between timber components, where deviations between the direction of force flow and the fiber orientation in the wood are present, which are recognized as structural weak points. This research investigates how anisotropic nodes can enhance force transfer between individual timber elements, thus allowing for load-adapted, slender component cross-sections. Maintaining precise control over anisotropy represents the pivotal strategy for developing a bio-based, material- and resource-efficient building system. Furthermore, we demonstrate how the concurrent development of a material system, fabrication methods, and an assembly strategy, in conjunction with the development of a computational frame¬work, yields a building system with a distinctive, material-driven aesthetic. The strength of the proposed material system and fabrication strategies are assessed in small-scale tests of three-valent planar nodes and four-valent spatial nodes. Additionally, the scalability and flexibility of a custom-developed design tool, fabrication processes, and assembly strategy are evaluated through a 1:1 demonstrator of a load-bearing, branching structure.

Abstract

Deployable gridshells are a class of planar-to-spatial structures that achieve a 3D curved geometry by inducing bending on a flat grid of elastic beams. However, the slender nature of these beams often conflicts with the structure’s load-bearing capacity. To address this issue, multiple layers are typically stacked to enhance out-of-plane stiffness and prevent stability issues. The primary challenge then lies in deploying such multi-layered systems globally, as it requires significant shaping forces for actuation. This paper presents an alternative design approach that involves strategically connecting compact-to-volumetric gridshell components using weaving principles to shape a thick segmented shell. This innovative approach allows for an incremental construc�tion process based entirely on deployable modules with volumetric configurations that locally provide the necessary structural depth for the entire system. To demonstrate this principle, we present the realization of BamX, a research pavilion constructed using deployable cylindrical components made from raw bamboo slats. These components are interconnected at carefully optimized interlocking woven nodes, resulting in a bending-active structural frame that is both strong and exceptionally lightweight. To determine the optimal topology and geometry of the pavilion, we employ an integrative computational approach that leverages advanced numerical optimization techniques. Our method incorporates a physics-based simulation of the bending and twisting be�havior of the bamboo ribbons. By finding the ideal locations for ribbon crossings, we ensure that all external and internal forces are in global equilibrium while minimizing the mechanical stress experienced by each ribbon. BamX exemplifies how a symbiosis of refined weaving craft and advanced computational modeling enables fascinating new opportunities for rethinking deployability in architecture.

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.