Workshop and Research Hall Diemerstein

Research-Design-Build Project

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figure: Diemerstein valley entrance, photo: Andreas Labes

Wood Campus Diemerstein

In the Diemerstein Valley, opposite Villa Denis, the first phase of construction, the workshop and research hall, has been completed. In addition to this real laboratory, further innovative timber structures, applied timber construction research, and experimental buildings with various uses are planned to be developed gradually. The buildings will be constructed with the involvement of students under the leadership of the t-lab research department. Together, they form the timber construction campus in the Diemersteiner Valley. The campus is intended to support the activities of the RPTU Kaiserslautern, such as regular workshops, summer schools, and the like. This will bring life to the valley and gradually enhance its value.

"SWR“ report on the wood campus Diemerstein

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figure: interior of the workshop, photo: Andreas Labes

t-lab workshop and research hall

Our strategy at the t-lab is to integrate student design with research and 1:1 implementation. The aim must be a closed-loop economy. The workshop and research hall in Diemerstein has emerged along this path. The timber construction derives its architectural form from the demand for a consistent circular economy of all building components, elements, and parts. The building, covering nearly 400 square meters, offers a flexibly usable space inside, suitable for workshops, seminars, and events. Additionally, it is intended for the construction and assembly of mock-ups as part of ongoing research projects

figure: Exterior of the workshop, photo: Andreas Labes

The design for the workshop building was developed and realized in collaboration with students. The requirement to build parts of the building themselves influenced considerations regarding component dimensions and connections. As a result, the hall was constructed by students under the guidance of professionals. The Research-Design-Build project thus links design, execution, and craftsmanship through this concrete example. It serves as a real-world laboratory for the circular economy.

figure: Students and experts setting up the hall

Design

The building is situated lengthwise in the valley, ensuring it doesn't obstruct existing cold air currents. The longitudinal sides of the simple structure feature three prominent, fixed circular openings for illumination. The entrance faces Villa Denis and the existing parking lot.

drawings: East view, North view

The end walls are made of translucent polycarbonate multiwall sheets and are set back, allowing the resulting roof overhang to serve both as a gathering space and storage area. The setback highlights the form of the frame structure and emphasizes the simplicity of the building.

figure: Facade of the building, photo: Andreas Labes

The core of the workshop and research hall is a multifunctional space, usable for constructing large-scale test specimens as well as for timber construction workshops, seminars, and conferences on t-lab research topics. The 360 square meter area is flexibly furnished and can be rearranged according to specific needs. Additional rooms (storage, toilets, utility room, wardrobe, kitchenette) are arranged around a freely standing wooden box in the entrance area.

The workshop and research hall is highly versatile, enabling various uses for different occasions. Even the fixed machinery is positioned to keep the space open. For conferences or larger gatherings, a mobile stage can be set up in front of the core area, providing unobstructed views for attendees seated in the central part of the hall. Equipment and movable workbenches are arranged along the outer walls and around the core.

Similarly, the space of the hall is used as a venue for lectures, project presentations, and seminars by RPTU Kaiserslautern-Landau or other institutions. Existing furniture and seating arrangements can be arranged and utilized on-site according to needs.

Primarily, the hall operates as a workshop and research facility. The existing machinery and workbenches provide students and researchers with a space and the opportunity to construct mock-ups, models, and other experiments.

Figure: Interior of the building, photo: Andreas Labes

Illustration: Visualisation of the supporting structure

Structure

The supporting structure of the hall consists of prestressed three-hinged frames with joints at the base nodes and at the ridge. The main load-bearing system consists of adjacent 12.50 meter wide frames made of laminated beech veneer lumber, which are arranged at 2.50 meter intervals.

Drawings: cross section and longitudinal section

The rigid eave nodes are resolved into beams, creating an efficient structure of tension and compression members. Depending on their load, the members are executed with two different cross-sections. The inner slender members are subjected to pure compression and are prone to buckling. Their cross-sections measure 160 x 200 mm. The outer members, subjected to tension and bending, are formed with a height of 300 mm and a width of 160 mm. The system is braced by wall and ceiling elements made of spruce cross-laminated timber (CLT).

Animation: Assembly sequence of the load-bearing structure

All components are elementised and reversibly connected to guarantee easy dismantling and subsequent reassembly without loss of value.

Illustrations: reversibly separable structure of the outer skin

Externally, a similarly reversible wall structure is followed: A layer of framed wood fiber insulation is followed by counter battens and vertical Douglas fir board cladding. Instead of a traditional reinforced concrete slab, a dismantlable cross-laminated timber (CLT) floor slab was utilized. Following the principle of a crawl space, CLT was elevated on steel beams which transfer the loads into micro-piles embedded in the ground to support the building. The individual elements of the structure, envelope, and technical installations remain clearly identifiable, ensuring a clean separation for future disassembly.

Cone Adapter

figure: Conical adapter: Model, installation

The conically milled cone adapters connect the roof and wall elements to the frames. These connectors are made of compressed laminated wood and are durable, dimensionally stable, and highly load-bearing.

Ring nodes made from compressed laminated wood

For the structural framework of the timber hall in Diemerstein, innovatively designed organic-shaped ring nodes made of compressed laminated wood have been developed. These are inspired by the natural shape of branch forks (crotches). Branch forks naturally have proportions that allow for a continuous redirection of forces through large radii. Unlike traditional nodes that can lead to stress concentrations, these organically shaped nodes do not create stress singularities. This results in improved performance with the same amount of material. By utilizing an organic form and orientation along the flow of forces, structurally efficient and architecturally delicate component connections can be achieved.

Figure: Installed ring nodes on the construction site

The ring nodes of the hall structure are made of compressed laminated wood with an average density of 1350 kg/m³. This is a high-performance wood composite based on technically compressed beech veneers. Initially, these veneers are impregnated with resin and then permanently bonded together under high pressure and temperature. The compression increases the proportion of wood fibers per unit volume, resulting in a significant increase in mechanical properties such as strength and stiffness. For the ring nodes, compressed laminated wood with a crosswise orientation of the individual veneer layers is used. This results in wood composite panels with orthotropic material properties, which remain consistent in the X and Y directions. Since the thickness of the KP panels is limited to about 70 mm during compression, the required thickness of 160 mm for the ring nodes is achieved by bonding partial panels. These are then machined into component nodes using CNC 5-axis milling machines.

Annimation: Joining ring knots and beech rods

The ring knots are designed in such a way that the construction beech beams can be screwed together via the inside of the ring using nuts and washers. For this purpose, threaded rods are first inserted into the end timber joints of the beech beams and anchored in rectangular steel load distribution plates. The beech beams are then connected to the corresponding nodes one after the other using the threaded rods. The bolt pretension required for the connection is applied using a torque spanner.

The four different component nodes of the hall construction were parametrized, taking into account both geometric requirements for component assembly as well as architectural and mechanical aspects.

illustration: Mockup and detail of eaves and ridge nodes

The ring nodes developed using parametric design tools were then validated through finite element simulations and mechanical tests, considering the orthotropic material structure and the predominant force situation at each node. Stress peaks were identified and continuously reduced through an iterative process using available script parameters. This led to the continuous static optimization of the node geometry.

figure: Illustration structure, reversibility

Conclusion

The "t-lab wood architecture and wood materials" research group is committed to a circular economy in the construction industry, requiring changes in education, research and practice. The workshop and research hall in Diemerstein combines architectural teaching with research, timber construction with modular, reversible connections for easy disassembly and reassembly without loss of value. The hall is designed to be fully recyclable and concrete-free, and all timber components are 100% reusable.