CLTと天然繊維が織りなすバイオベース建築
軽量かつ高強度を実現する新たなシステムを用いた〈ハイブリッド亜麻パビリオン〉
© Roland Halbe
© ICD_ITKE_IntCDC_University of Stuttgart
〈ハイブリッド亜麻パビリオン（Hybrid Flax Pavilion）〉は、ドイツ南部の街ヴァンゲンにて開催されている庭園博「ランデスガルテンシャウ2024（Landesgartenschau 2024）」のために建てられた展示棟です。
薄いCLT材と亜麻繊維で構成されたハイブリッド・システムで構成された特徴的な屋根は、より軽量かつ資源効率の高い構造をつくり出しつつ、成長の早い天然繊維を建築に活用することが可能であることを実証しています。
シュトゥットガルト大学にて建築のコンピュテーショナル・デザインを研究する「IntCDC」による、統合的なコンピュテーショナル・デザイン・プロセスと高精度のプレファブリケーションを活用したプロジェクトです。
これまでに取り上げたシュトゥットガルト大学のプロジェクトはこちら
（以下、University of Stuttgartから提供されたプレスキットのテキストの抄訳）
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
〈ハイブリッド亜麻パビリオン〉は、曲がりくねった川の岸辺で開催されているランデスガルテンシャウの敷地内に建つ展示棟である。起伏のある屋根と円形のガラスファサードが特徴的なそのデザインは、来館者をあらゆる方向から印象的な屋内空間へと誘う。
完全に透明な外壁は、建物内部と外部の景観をシームレスに融合させるパノラマビューを提供する。また、近くを流れるアルゲン川のリズムに呼応するように起伏する屋根が、連続的かつ明確な空間ゾーンをつくり出す。
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
その中心には気候庭園があり、中庭として機能しつつ自然な相互換気と冷房を促進する。リサイクル・コンクリートとCO2削減セメントでつくられた地熱活性床スラブとともに、最小限の設備で年間を通して快適な室内環境を確保する。
このパビリオンは、シュトゥットガルト大学のIntCDC（Integrative Computational Design and Construction for Architecture）が、従来の建築手法に代わるものとして開発した、木と天然繊維で構成するハイブリッド建築システムを紹介している。
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
バイオベースの新工法を実証する常設展示棟
このユニークなハイブリッド・システムは、薄いCLT材と、ロボットによって巻きつけられた亜麻繊維の天然繊維体を組み合わせた、地域に根ざしたバイオベースの材料でつくられた、資源効率の高い斬新な建築構造を実現する。
亜麻は地域の歴史ある紡績工場で加工されており、この紡績工場はランデスガルテンシャウの一部として改修された。
© Roland Halbe
20のハイブリッド・パーツが通常の木材プレートと交互に配置され、380m²の展示スペースを覆う波のような屋根を形成している。
このハイブリッド建築システムの目標は、材料の使用量を最小限に抑えながら、柱のない広々とした空間を実現することであり、木材と天然繊維の複合材料による相乗効果を活用している。
統合的なコンピュテーショナル・デザイン・プロセスと高精度のプレファブリケーションにより、44の天井部材の現場での組み立ては8日間で完了した。
© Roland Halbe
分野横断した開発アプローチの有効性を示すパビリオン
このパビリオンの設計には統合的な計算手法を活用するとともに、さまざまな分野の専門家の意見をシームレスに取り入れることで、研究と産業のギャップを埋めている。
このアプローチは木材と繊維を活用する「ファイバー・ティンバー・ハイブリッド・システム」の設計だけでなく、ファサードや屋根材のような従来の建築要素とのインターフェースも考慮に入れており、柔軟かつ反復的な設計プロセスを促進し、開発のあらゆる段階で関係するすべての分野にわたる調整と最適化を可能にした。
その結果、設計、製造、建設のプロセスはわずか12カ月で完了しており、この統合的なコ・デザイン・アプローチの有効性が実証された。
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
成長の早い天然繊維を活用することで地域の木材の可能性を引き出すハイブリッド建築システム
ファイバー・ティンバー・ハイブリッド・システムは、木材と天然繊維の特質を活かし、軽量で効果的、かつ優れた性能を発揮する建築部材を生み出す。
薄い木材要素を補強するために亜麻繊維コンポーネントを組み込むことで、建設業界にとって成長の早い資源の利用が容易となり、地域で入手可能な木材量で、より効果的に木材の大きな需要を満たすことができる。
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
この建築システムは、サーキュラー型建築の原則に従い、部材の分別による再利用やリサイクルを可能にするために開発されている。ハイブリッド・コンポーネントは、構造高さを変えられる単純支持の梁のような構造を目指している。
ファイバーボディは主に引張荷重を受ける底面を形成し、木材パネルは圧縮力を受けるように構成されており、両者が一体となって、アルプス山麓の高い積雪荷重を支えるのに必要な強度と剛性を実現している。
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
© ICD_ITKE_IntCDC_University of Stuttgart
以下、University of Stuttgartのリリース（英文）です。
Hybrid Flax Pavilion
Landesgartenschau Wangen im Allgäu, 2024The Hybrid Flax Pavilion constitutes a central exhibition building on the grounds of the Landesgartenschau, located on the winding banks of the recently revitalised Argen River. The pavilion showcases a novel wood-natural-fibre hybrid construction system developed by the Cluster of Excellence “Integrative Computational Design and Construction for Architecture” (IntCDC) at the University of Stuttgart, as an alternative to conventional building methods. The unique hybrid system combines thin cross-laminated timber with robotically wound flax fibre bodies to create a novel, resource-efficient building structure made from regional, bio-based materials with a distinct local connection. Flax was historically processed in the local textile industry, whose old spinning mill was renovated as part of the Landesgartenschau. The pavilion’s gently undulating roof, together with its circular floor plan and centrally located climate garden, creates an exhibition space that seamlessly integrates into the surrounding landscape. The geothermally activatable floor slab made of recycled concrete provides year-round comfortable use of the permanent building.
A permanent exhibition building demonstrating novel bio-based construction methods
Situated on the lush grounds of the Landesgartenschau, the Hybrid Flax Pavilion provides a central exhibition space. Its design features an undulating roof and a circular glass facade that invites visitors to the striking indoor space from all directions. The fully transparent envelope provides panoramic views which seamlessly blend the interior of the building with the exterior landscape. Echoing the rhythm of the adjacent Argen River, the undulating roof creates continuous yet distinct spatial zones, providing a sense of depth that connects the inner and outer facades. At its core lies a climate garden, serving as an inner courtyard and facilitating natural cross-ventilation and cooling. Together with a geothermally activated floor slab made from recycled concrete and CO2-reduced cement, this ensures year-round indoor comfort with minimal building services.
The pavilion’s roof constitutes the first-ever hybrid structure of cross-laminated timber plates and natural fibre bodies produced through coreless flax filament winding. The 20 hybrid components alternate with regular timber plates to form the distinctive wave-like structure of the roof, which covers the 380m² exhibition space. The goal of this novel hybrid building system is to achieve expansive column-free space while minimising material usage, thus leveraging the synergy between wood and natural fibre composites. The onsite assembly of all 44 ceiling elements was completed in 8 days owing to the integrative computational design process and high-precision pre-fabrication.
The building’s design makes use of integrative computational methods to seamlessly incorporate input from various specialists across different fields, bridging the gap between research and industry. This approach encompasses not only the design of hybrid fibre-timber components but also considers interfaces to conventional building elements like the facade and roof, taking into account their interconnected geometric and constructional requirements. This methodology facilitated a flexible, iterative design process, allowing for adjustments and optimisations at every stage of development across all involved disciplines. As a result, the design, manufacturing, and construction process took only 12 months, demonstrating the effectiveness of this integrative Co-Design approach. In the spirit of two-way knowledge transfer between cutting-edge research and construction companies, the building also shows how highly innovative architecture can be built by regional, small enterprises and skilled craftspeople.
Novel hybrid building system using natural fibres
The fibre-timber hybrid system leverages the distinctive qualities of timber and natural fibres, resulting in lightweight, effective building components with superior performance. Incorporating flax fibre components to reinforce the thin wooden elements facilitates the use of fast-growing resources for the construction industry, allowing the significant demand for wood to be met more effectively from locally available timber reserves. The construction system is being developed to enable future material reuse or recycling through the sorted separation of components, following principles of circular construction. The hybrid components aim to achieve a simply supported, beam-like structure with a variable structural height. The fibre body forms a bottom surface that primarily bears tension loads, while the timber panel manages compression forces and constitutes the surface for the roof enclosure. Together they provide the strength and stiffness necessary to carry the high snow loads at the foothills of the Alps.
Throughout the research and development process, the design of the fibre body was continuously informed by feedback from architectural requirements, structural analysis, fabrication constraints, and material properties. It consists of multiple, sequentially wound flax fibre layers. The primary spine layer aligns with the beam direction, acting as a bottom cord at the centre of the span. The fan layer gradually disperses loads to the edge supports, while the visually dominant lattice layers create a uniform fibre mesh to achieve the required structural integrity. Two additional corner reinforcement layers enhance fibre interaction and provide additional reinforcement in structurally critical areas.
The simply supported, fibre-timber hybrid components cover an 8.6-meter span between linear supports. The radially arranged 120mm thick cross-laminated timber (CLT) plates constitute the primary framework and create the undulating roof profile. The timber plates were manufactured using a 5-axis milling machine and include a series of thru-holes for the timber-fibre-facade connections as well as chamfered edges that continuously change their angle to match the varying orientations of the fibre connections. Flax fibre bodies are affixed by screws beneath every second CLT plate, establishing the hybrid components. Full-scale load tests allowed for the calibration of finite element models and confirmation of the material systems’ structural integrity.
From robotic prototyping to industrial filament winding
The coreless filament winding process utilised in the development and production of the fibre elements allows for the selective local deposition of material driven by specific structural, architectural, and material requirements. In contrast to conventional fibre composite fabrication processes, this is achieved without the need for a surface mould, as the winding frame is co-designed with the fibre element so that the element’s final fibre body emerges in the winding process as the equilibrium state of all fibre segments interacting. This project required further adaptation of the coreless filament winding process to accommodate the natural flax fibre material system and unique geometric form of the fibre body of the hybrid component.
This fibre geometry represents a departure from previous geometries because of its use of positive surface curvatures. Typically, positive curvatures are only achievable by a mould, yet this component employs areas of both positive and negative Gaussian curvature. To achieve this, the winding frame includes a “spine” that allows for the positive curvature of the component in its longitudinal direction as well as negative curvature, structural depth, and radius of curvature in its cross-section, all while providing the necessary structure to make the frame self-supporting. Anchor points around the perimeter of the frame were specifically oriented based on the normal of the geometric surface to maintain consistent fibre direction and properly transmit forces from the timber into the fibre bundles, a requirement paramount to the effectiveness of the hybrid component.
Using this custom frame, the geometry, fibre patterns, and fabrication processes were tested and refined at University of Stuttgart through a series of prototypes wound by a 6-axis robotic arm equipped with a custom end effector. After the prototypes were completed and structurally evaluated, the finalised design was handed over to the industrial partner for serial production using a 5-axis industrial filament winding machine. The fabrication planning was directly integrated into the computational design process and a custom tool converted the geometric data of the fibre component into executable machine code, streamlining the design-to-fabrication workflow and successfully bridging the gap between research and industry.
Research into computationally enabled, bio-based hybrid building systems is being continued at the University of Stuttgart as part of the Cluster of Excellence “Integrative Computational Design and Construction for Architecture”.
「Hybrid Flax Pavilion」University of Stuttgart 公式サイト
https://www.icd.uni-stuttgart.de/projects/hybrid-flax-pavilion/
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