德国乌尔巴赫塔 | 自成型木材的现代建筑表现

乌尔巴赫塔是一个独特的木结构建筑。这座塔的设计和构建源于一个弯曲木制构件的全新自成型过程。这种具有首创性和先驱意义的发展使得木材的加工制造有了一个范式的转变，将一种需要重型机械来辅助加工的精细却耗能的机械制造工艺，转变为了一种可以依靠材料自身来独立完成整个制造过程的工艺。这种形状的变化完全得益于木材本身的特性，即在自身含水量降低时会自发收缩。在最初的设计和制造中，这座14米的高塔的所有组成构件都是平面的，并在工业标准下的技术干燥过程中自动转变为最终的曲线造型。通过可持续、可再生和当地的建筑材料，为高性能的、精妙的结构体量创造了一种全新的、意想不到的建筑上的可能性。

The Urbach Tower is a unique wood structure. The design of the tower emerges from a new self-shaping process of the curved wood components. This pioneering development constitutes a paradigm shift in timber manufacturing from elaborate and energy-intensive mechanical forming processes that require heavy machinery to a process where the material shapes entirely by itself. This shape change is driven only by the wood’s characteristic shrinking during a decrease of moisture content. Components for the 14 m tall tower are designed and manufactured in a flat state and transform autonomously into the final, programmed curved shapes during industry-standard technical drying. This opens up new and unexpected architectural possibilities for high performance and elegant structures, using a sustainable, renewable, and locally sourced building material.

▼乌尔巴赫塔外观，exterior view of the Urbach Tower

乌尔巴赫塔是世界上第一个由自成型的建筑规模组件构成的建筑结构。它不仅向人们展示了一种创新的制造方法和由这个制造方法所创造出的新颖木结构；更在乌尔巴赫市中建造了一个引人注目的地标性建筑，从而加强了游客的空间参与感和景观体验感。

▼塔结构受变形、表面干燥脱水和组合角度的影响，FEA model of tower structure including deformations, and utilization of surface and connections

The Urbach Tower constitutes the very first structure worldwide made from self-shaped, building-scale components. It not only showcases this innovative manufacturing approach and resultant novel timber structure; it also intensifies the visitors’ spatial involvement and landscape experience by providing a striking landmark building for the City of Urbach’s contribution to the Remstal Gartenschau 2019.

▼乌尔巴赫塔外观，世界上第一个由自成型组件构成的建筑结构，exterior view of the Urbach Tower that is the very first structure worldwide made from self-shaped, building-scale components

Rems Valley 中独特的建筑地标

Unique architectural landmark for the Rems Valley

2016年，一部分最为著名的德国建筑师为Remstal Gartenschau 2019设计了16个车站，Urbach塔便是其中之一。这些车站作为小型的永久性建筑，呼应了散落在风景优美的Rems Valley的田野和葡萄园中的传统白色小教堂。这座14米高的塔体位于山谷中心地带一个显眼的山坡上，作为一个突出的地标，连接着好几个车站。通过展示令人惊叹的远景、限定景观视野，这座塔提供了一个可以用来休息的庇护所，人们可以在塔内静思，也可以远眺山谷的景色。塔身独特的形式展示了木材这种传统建材在当今时代下的一种十分现代的建筑表现形式。它以向上的螺旋形状来诉说自成型木材与生俱来的自然特性。

The Urbach Tower is one of 16 stations designed by some of the most renowned German architects for the Remstal Gartenschau 2019. The stations are small, permanent buildings that evoke the traditional white chapels distributed in the fields and vineyards along the scenic Rems Valley. Located on a prominent hillside in the center of the valley, the 14 m tall tower is a striking landmark that visually connects several stations. It provides a place of shelter, internal reflection and outward view by revealing stunning vistas and framing the landscape. The distinctive form of the tower constitutes a truly contemporary architectural expression of the traditional construction material wood. It celebrates the innate and natural characteristics of self-shaped wood in its upwards spiraling shape.

▼乌尔巴赫塔外观，采用向上的螺旋形状，the exterior view of the Urbach Tower with the upwards spiraling shape

外部结构的凹曲率形成了干净利落的轮廓线条和清晰的表面，而随着时间的推移，日间的直射阳光和落叶松木覆层的白化过程更将进一步地加深这种曲率。相比之下，在塔体内部，木材结构看起来像纺织品一般柔软，而略微起伏的表面则进一步突出了这种轻柔感，由此，凸起的曲率在视觉和触觉上创造出一种意想不到的材料体验。在塔身入口的对面，薄薄的木质外壳就像窗帘一样打开，将Rems Valley的美景置于视野的正中间。

The concave curvature of the structure on the outside results in sharp lines and crisp surfaces, which is further accentuated by direct day light and whitening of the larch cladding over time. In contrast, on the interior the convex curvature creates an unexpected visual and tactile material experience, with the timber structure appearing to be almost soft and textile-like, highlighted by the light washing the gently undulating surfaces. Opposite the entrance, the thin wood envelope opens like curtain, putting the Rems Valley on center stage.

▼乌尔巴赫塔外观，外部结构的凹曲率形成了干净利落的轮廓线条和清晰的表面，exterior view of the Urbach Tower, the concave curvature of the structure on the outside results in sharp lines and crisp surfaces

材料的编程设计和形状变化的可预测性

Material programming and predictability of shape change

在木结构中，木材的含水量通常会导致开裂和变形等问题；因此，必须小心谨慎地控制木材中的水分变化和应力发展趋势。相比之下，在本项目中，建筑师通过对木材的精心设计和特殊布置，巧妙地利用了这种强大的、自发形成的变形，从而触发了一种自成型的设计过程。众所周知，可以通过对机器进行编程设计来使它们执行不同的运行命令，同样的，在本项目中，建筑师也对木材部件进行了编程设计，从而使得它们在干燥的过程中，逐渐转变为预设的形状。

▼木材在脱水干燥过程中的自成型，self-shaping wood manufacturing through drying

In timber construction, moisture typically causes problems with cracking and deformation; hence, moisture changes and stress development must be carefully controlled. In contrast, in this project wood is programed and arranged in a way to utilize this powerful, naturally occurring deformation to trigger a designed self-shaping behavior. In the same way that machines can be programmed to perform different movements, wood parts can be programmed to transform into predetermined shapes when dried.

▼乌尔巴赫塔外观，利用自发形成的变形打造“小蛮腰”般的造型，exterior view of the Urbach Tower with a waist, utilizing naturally occurring deformation to trigger a designed self-shaping behavior

虽然这种“将木材弯曲成不同的形状以达到结构和美观的要求”的方法已经存在了好几个世纪，并已经成为了一种公认的工业化制造过程，但这个过程在很大程度上仍然主要依靠粗糙的机械力来实现成型过程。类似地，在实践活动和学术研究中，由含水量变化所导致的木材变形规律也是众所周知的。然而，设计思维的转变以及可用于更准确预测的新型计算模拟机制使得我们可以通过利用这种由含水量变化引起的膨胀和收缩特性，来设计和规划一种更大尺度上的、特定的自成型运动。

While methods of bending wood into different shapes for structure and aesthetics have existed for centuries and have become recognized industrial processes, they still mostly rely on brute mechanical force for the shaping process. Similarly, an understanding of how wood deforms due to changes in moisture content is well known in practice and academics. However, a shift in design thinking, as well as new computational simulations for more accurate prediction, now allow us to use this moisture induced swelling and shrinking to design and program specific self-shaping movements at larger and larger scale.

▼乌尔巴赫塔外观，exterior view of the Urbach Tower

建筑尺度下的自成型制造过程

Self-shaping manufacturing at building-scale

这种大规模尺度的自成型过程具有开拓性，从而构成了木材制造领域的范式转变，将一种需要重型机械来辅助加工的精细却耗能的机械制造工艺，转变为了一种可以依靠材料自身来独立完成整个过程的工艺。这种形状的变化完全得益于木材本身的特性，即在自身含水量降低时会自发收缩。在最初的设计和制造中，这座塔的所有弯曲交叉层压木材（CLT）构件都是平面的，随后再在干燥脱水的过程中，自动变形为预设好的弯曲形状。5.0 m x 1.2 m的云杉木双层构件在制造时有着较高的含水量，并经过了特殊的绞合处理，随后再在工业标准下的技术干燥过程中自动转变为最终的曲线造型。当将云杉木才从干燥室中移出来的时候，它就已经达到了一种精确的弯曲程度。建筑师将这些部件重叠并层压在一起，从而在特定的位置限定出一个几何造型，再依靠这种具有形状稳定性的几何造型来形成较大尺度的弯曲CLT部件。

The pioneering development of large-scale self-shaping constitutes a paradigm shift in timber manufacturing from elaborate and energy-intensive mechanical forming processes that require heavy machinery to a process where the material shapes entirely by itself. This shape change is only driven by the wood’s characteristic shrinking during a decrease of moisture content. The curved Cross Laminated Timber (CLT) components for the tower’s structure are designed and produced as flat panels that deform autonomously into predicted curved shapes when dried. The 5.0 m x 1.2 m spruce wood bilayers parts are manufactured with a high wood moisture content and specific layups and dried in an industry standard technical drying process. When removed from the drying chamber the parts are precisely curved. The parts are overlapped and laminated together to lock the geometry in place, forming larger curved CLT components with form stable geometry.

▼乌尔巴赫塔外观局部，塔身由木材自发变形限定而成，partial exterior view of the Urbach Tower defined by the self-shaped wood boards

建筑师通过开发材料特定的力学计算模型，来设计、预测和优化材料的布置状态，从而产生所需要的不同曲率类型和半径。通过使用可持续、可再生和当地的材料，实心木板的自成型制造技术，以及制造工艺对于不同曲率的快速适应性为薄壳结构创造了一种全新的、前所未有的建筑可能性。值得一提的是，乌尔巴赫塔也是该技术在建筑规模尺度和承重木结构上的首次应用所创造出的实际建筑物。

Material specific computational mechanics models have been developed to both design, predict, and optimize the material arrangement required to produce different curvature types and radius. The technology of self-shaping manufacturing for solid timber boards and the rapid adaptability of the process to different curvatures open up new and unexpected architectural possibilities for thin shell wood structures, using a sustainable, renewable, and locally sourced building material. The Urbach Tower is the very first implementation of this technology on building-scale, load-bearing timber parts.

▼乌尔巴赫塔外观局部，partial exterior view of the Urbach Tower

可持续的木结构和功能性的木材表皮

Sustainable wood construction and functional timber cladding

自成型构件完全由来自瑞士的云杉木板制成。单个构件的半径为2.4米，跨度可以达到15米，在这种情况下，结构厚度仅为90毫米。这些构件都是使用5轴CNC技术切割而成的，采用半圆柱坯料进行详细设计，建筑师将塔身预先拆分组装成三个包括防水层和外部木材表皮在内的建筑构件群组，以方便运输。通过精确的曲率和制造过程中的最佳纤维对准处理，每个组件的详细机器切割过程均仅需要90分钟。此外，建筑师还在组件外侧额外覆上了由胶合层压落叶松木材打造而成的定制保护覆层。值得一提的是，这个保护覆层中还包括一种透明且具有持久性的无机涂层，可以保护木材免受紫外线的辐射和真菌的侵袭。并且，当被置于全室外环境中时，落叶松木材不仅不会开裂且逐渐变为银灰色，反而会随着时间的流逝而呈现出一种均匀的白色。

The self-shaping components are made entirely of spruce wood boards sourced regionally from Switzerland. Individual components span up to 15 m with a radius of 2.40 m and a structural thickness of only 90 mm. The components are 5-Axis CNC cut and detailed from half cylinder blanks and pre-assembled into building groups of three components for transport, including water barrier and external wood cladding. With precise curvature and optimal fiber alignment from the manufacturing process, each component is cut in detailed in just 90 minutes of machine time. A custom-made protective cladding layer consisting of glue laminated larch wood is added on the outside. This also includes the application of a transparent and durable inorganic coating, which protects the wood from UV radiation and fungi attack. Instead of ripping and turning silver-grey when exposed to outdoor weathering, the larch wood will take on an even white color over time.

▼乌尔巴赫塔外观局部，塔内为人们提供了休息停留和远眺观景的空间，partial exterior view of the Urbach Tower that provides shelter and viewing space for people

从在锯木厂中切割当地的原木料，到自成型板的生产，到干燥过程，再到最终的加工和预组装过程等，整个工艺链都由同一组公司负责，在同一个地点进行。这不仅可以实现一种可持续且具有创新性的生产机制，同时还可以向人们展示自成型的制造过程是如何无缝地将自己整合到已建立的工业木材加工和制造工作流程中的。

The entire process chain, from cutting regional logs in the sawmill to the production of the self-shaping panels, the drying process and final machining and pre-assembly takes place within the same group of companies and at the same location. This not only allows for sustainable and innovative production, but it also shows, how the self-shaping manufacturing can seamlessly integrate in established industrial wood processing and manufacturing workflows.

▼乌尔巴赫塔内部仰视，使用透明的屋顶，looking up to the top of the interior tower with a transparent roof

高性能的薄壳木结构

Thin-shell high-performance timber structure

乌尔巴赫塔由12个弯曲的构件组成，而这些构件则由交叉层压木板打造而成。塔身的承重结构的厚度仅为90毫米，而与此同时，还设有一个14米的悬臂结构，这就创造出一个160/1的厚宽比。固有的曲率创造出一个非常纤细且轻质的塔体结构，每平方米的表面积的自重仅有38千克。在组装状态下，塔体通过其富有表现力的弯曲几何造型充当着表面活化结构。轻质的建筑元件通过左右交叉螺纹连接，建筑师根据功能要求对螺纹进行了精心布置，甚至连角度都是特定的，从而使得这些螺纹能够在整个建筑结构中最大限度地发挥自己的作用，同时，这种处理方法还能够保持接缝处的连续性，从而实现均匀的荷载传递。

The Urbach Tower consists of 12 curved components made from cross-laminated timber. The tower’s load-bearing structure exhibits a thickness of 90mm while cantilevering over 14 meters resulting in a span to thickness ration of approximately 160/1. The inherent curvature enables a highly slender and lightweight tower structure of only 38 kg per square meter surface area. In the assembled state, the tower acts as a surface-active structure through its expressive curved geometry. The lightweight building elements are connected by crossing screws, the arrangement and specific angle of which is optimised throughout the structure in relation to their utilization while preserving a continuous connection along the seam for homogeneous load transfers.

▼施工过程，脱水干燥后自成型的双层木材，construction process, self-shaped wood bilayers after drying

▼施工过程，弯曲后的CLT构件，construction process, completed curved CLT components

▼施工过程，落叶松木材的塔身部件组装完毕，construction process, completed assembly groups with Larch façade

塔体的预制装配分组进行，每组都由三个弯曲的构件组成。四名工匠组成一个团队，在不使用大量脚手架或是模板的情况下，一个工作日便能完成组装过程，甚至还能在各组塔体的顶部覆盖一层透明的屋顶。这个结构由大师级工艺、数字化创新和科学研究共同创造，展示了木结构在高效、经济、生态和表现力等方面的可能性。

The prefabricated assembly groups of the tower, each consisting of three curved components, were assembled in a single working day by a team of four craftsmen without the requirement of extensive scaffolding or formwork, and topped-off by a transparent roof. The structure showcases the possibilities for efficient, economical, ecological and expressive wood architecture that arises at the intersection of master craft, digital innovation and scientific research.

▼施工过程，乌尔巴赫塔的塔身分组运至现场，construction process, assembly groups in transport to Urbach

▼施工过程，CLT弯曲部件的现场组装，construction process, on site assembly of curved CLT structure

Project Team:

ICD – Institute for Computational Design and Construction, University of Stuttgart

Prof. Achim Menges, Dylan Wood

Architectural Design

Self-forming Curved Wooden Components Research and Development

ITKE – Institute of Building Structures and Structural Design, University of Stuttgart

Prof. Jan Knippers, Simon Bechert, Lotte Aldinger

Structural Design and Engineering

Scientific collaboration:

Laboratory of Cellulose and Wood Materials, Empa (Swiss Federal Laboratories for Materials Science and Technology), Switzerland & Wood Materials Science, ETH Zurich (Swiss Federal Institute of Technology Zurich)

Dr. Markus Rüggeberg, Philippe Grönquist, Prof. Ingo Burgert

Self-forming Curved Wooden Components Research and Development (PI)

Industry collaboration:

Blumer-Lehmann AG, Gossau, Switzerland

Katharina Lehmann, David Riggenbach

Self-forming Curved Wooden Components Research and Development,

Wood Manufacturing and Construction

Project Support:

Gemeinde Urbach

Remstal Gartenschau 2019 GmbH

German Federal Environmental Foundation (Design, Fabrication and Engineering Methods for the application of curved wood elements in high-performance, resource-efficient wood construction: Project Tower Urbach, Remstal Gartenschau 2019)

Innosuisse – Swiss Innovation Agency (Smart, Innovative Manufacturing of Curved Wooden Components for Architecture with Complex Geometry)

Carlisle Construction Materials GmbH

Scanntronik Mugrauer GmbH

Project Data:

Dimensions

• 14.20 m tall timber structure

• 4.0 m radius bottom, 3.0m radius top, 1.6m radius middle

• Spruce Wood CLT with 10-30-10-30-10 build up

• Larche Wood façade with titanium oxide surface treatment

• 5 axis CNC cut components

• 12 individual prefabricated components pre-assembled in groups of 3

• Crossing screw connection detail with wood alignment blocks

• 8 Sensors to monitor internal WMC of the structure

Construction System:

Curved surface active tower structure, self-shaped curved cross laminated spruce timber (CLT) 10 -30-10-30-10 layup, glue laminated Larch façade with titanium oxide UV protection surface treatment, curved polycarbonate roof with steel support structure.