The Wangenturm on the grounds of the 2024 State Garden Show in Wangen im Allgäu is the world's first accessible observation tower made of load-bearing, self-forming wooden components. Under the leadership of Prof. Achim Menges (Institute for Computational Design and Construction ICD) and Prof. Jan Knippers (Institute for Structural Design and Engineering (ITKE)), the IntCDC Cluster of Excellence "Integrative Computational Design and Construction for Architecture" at the Faculty of Architecture and Urban Planning at the University of Stuttgart developed this pioneering wooden tower.
While moisture-induced shrinkage and warping are generally considered a disadvantage in timber construction, the 23-meter-high tower in the Allgäu region embraces this challenge, achieving its striking silhouette, reminiscent of an aesthetically delicate origami fold, only through this process. Its self-formed, double-layered panels made of local spruce wood consist of a 30-millimeter-thick "active" layer and a 10-millimeter-thin "restrictive" layer, cross-laminated. In contrast to industrial processing, these boards were only lightly air-dried, and the "active" layer was then pressed to the "restrictive" layer using a vacuum press. The wood panels were glued together. The subsequent controlled drying process caused the active layer to shrink perpendicular to the grain of the boards, allowing the wooden panels to curve into the pre-calculated, distinctive shape.
The wooden tower itself consists of twelve of these load-bearing wooden panels. These form a surface-active structure that bears the horizontal wind loads and gains additional rigidity through its curvature. The spiral staircase inside the tower additionally supports the vertical traffic loads of the structure. The spiraling interior receives daylight through its three tower entrances. This creates a playful interplay of light and shadow on the curved wooden panels, further emphasizing the delicate aesthetics of the tower's interior.
The Wangen Tower is not only an interface between research, craftsmanship, and computer-aided planning and prefabrication. It is also an aesthetic landmark for efficient, ecological, and regionally sourced construction, accessible to everyone.
