Buildings Ambassador Award and Award of Excellence
Taiyuan Botanical Garden Domes StructureCraft
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Complex geometry The site features three paraboloid domes, ranging from 43 to 88 m in diameter and 12 to 30 m in height. The gridshells comprise light, doubly curved glulam beams, arranged in two or three crossing layers. Timber was chosen due to its adaptability to the project’s geometric demands, as well as its inherent fire resistance, structural flexibility, natural esthetic and environmental sustainability. Working with Austria’s Delugan Meissl Associated Architects (DMAA), StructureCraft’s engineers developed an optimized geometry while considering daylighting, structural performance, shipping, fabrication and preassembly, all of which were meticulously described with digital files and kit-of-parts erection and sequencing drawings for site crews. Domes are usually constructed for efficiency using triangulation in their surface. For architectural and sunshading reasons, this project’s architect and client wished to create a more tightly spaced grid on one side and more open fan on the other. This resulted in a ‘seashell’ shape, with each glulam member unique and many of them doubly curved. Further, domes are usually spherical, leading to more repetitive patterns in their surface. The client and architect were insistent on a unique paraboloid, if it could be built economically and its structural efficiency could be enhanced, given its less stable, non-triangulated surface. 24
CANADIAN CONSULTING ENGINEER
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The glulam lattice panels were prefabricated with half-lap scarf joints.
One part of the solution was a geodesic design. Custom scripts were written in the latest computational geometry software to optimize the precise shape of the paraboloid. This would minimize waste in the doubly curved glulam pieces, while ensuring structural efficiency. To prevent buckling resulting from the non-triangulated surface, a light grid of cable diagonal bracing was engineered and installed below the gridshell surface. Of course, the structure needed to be constructible. Building piece-by-piece up to 30 m in the air, expecting it all to fit with structural forces properly transferred, would be impossible. The solution lay in precisely prefabricating a pattern of roughly 10 x 12-m modules that could be placed on shoring towers and stitched together using simple, custom-designed scarf joints.
PHOTOS COU RT E SY ST RUC T U R EC R A F T.
he city of Taiyuan wanted to create a world-class botanical garden under three long-span gridshell domes. Rather than steel, the domes would be constructed using wood, a more sustainable and esthetically pleasing material. Canadian firm StructureCraft supplied structural engineering for a unique paraboloid scheme. With the largest dome at 88 m, it stands as the longest clear-span, non-triangulated timber gridshell in the world.
September/October 2021
2021-10-18 10:14 AM
