Idaho Central Credit Union Arena
Long-span Timber Sports Arena
The University of Idaho basketball arena models the use of timber in long-span sports facilities in North America.
The 4,200-seat arena is the new home for the Vandal's varsity basketball teams and a gathering place for a variety of school and community events.
StructureCraft joined the consultant team at concept design as the Structural Engineer of Record for the timber superstructure, taking on responsibility for both gravity and lateral load resisting systems, including seismic design.
The University of Idaho wished to use donated local Glulam for most of the project, and we worked closely with two different local Glulam manufacturers in Idaho to produce the curved Glulam.
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Design
We were heavily involved in the concept design process with Opsis Architecture, shaping the curved roof and optimizing for fabrication and constructability, while still maintaining architectural intent and constraints. The roof is a doubly curved plywood diaphragm, a unique structural concept which acts as a deep beam for seismic loads, allowing the roof to span 360 ft. between its ends without requiring interior bracing.
One of the many unique features of this project is the portal frame that spans 120’ to allow for viewing from the secondary seating at the practice rink. Complex timber engineering was required to design the thrust connection between beam and column to transfer over 450,000 lb. of compression. Kingpost trusses span over 150 ft. across the main arena.
Fabrication
Our 3D model produced all the geometry and shop drawings required to produce the curved Glulam shapes. Our skilled shop team used our in-house CNC machine along with layout optimization to cut the desired shapes out of the actual curved billets we received from the Idaho manufacturers. We also “test fit” each of the major assemblies in our shop, ensuring fit prior to shipping the components to site.
Installation
The entire portal frame was pre-assembled on site into three large components weighing over 50,000 lb. to minimize work at height.
One of the key challenges was installation of heavy elements with a crane in the bowl. We used a parametric model of the trusses with genetic algorithms to perform a structural optimization on the trusses, significantly reducing the weight of the prefabricated pieces. This also allowed the project budget to be maintained.