Industrial Enclosures

Toroids for 200' x 500' enclosure (160,000mt)
Span: 60m (200ft), Rise: 30m (100ft)
Seismic Zone 4
Owner: Minera Escondida Limitada (MEL)
Project Partners: BHP Billington, Duke 
Power, Fluor Daniel Chile, Bechtel, 
Yolles, Cade-Idepe Montayes Delta 
Limitada, Santiago Chile

Stockpile material is deposited via the 8m x 9m roof gantry along the crown of the structure. These severe line loads & dynamic forces are transmitted to the foundations via 14 lateral steel arch trusses spaced 12m apart. The design allows for any single truss becoming ineffective in the event of equipment malfunction. Triodetic framing between the trusses is designed as a series of curved single layer shells (toroids) spanning 200ft x 50ft and rising to 100ft at the roof apex. The frame sections were all pre-assembled at ground level & sequentially positioned with stand-off brackets to accept linear horizontal purlins, curved decking & translucent panels. The end walls are designed as vertical two layer space frames & were installed as two pre-assemblies. The walls require no intermediate foundations & can be re-located in their assembled state in the future when the stockpile & building length are extended. Other advantages of the Triodetic solution beyond the prime purpose of dust suppression, included avoidance of scaffolding & working at height, reduced foundation loads versus an A-frame building alternative, added space for material handling equipment, and an efficient construction sequence that held this activity off the project critical path.