IndoMalayan Pavilion, Metro Toronto Zoo – Ron Thom
I wish I could find some better photographs about what seems a fascinating project. The story here explains that that pavilions shown here
are constructed as a series of irregularly faceted hyperbolic paraboloid roof planes covering a similarly irregular topography. At the outset, Ron Thom had wanted to avoid making what he called a "prison for animals," aiming for spaces as non-building-like as possible, in a "continuous environment of humans, flora and fauna."
The geometry of the plan … is brilliantly simple, yet appears as a complex abstracted landscape as varied as the natural landforms that surround it. [It uses] … hyperbolic paraboloid structures [made with] the Triodetic system of aluminum tubes and joints. Each building is an assembly of two modules, 42-foot squares and rhomboids, with 90-degree, 60-degree and 30-degree corners. An infinite variety in surface topography is made possible simply by varying the apex and base of each section of the roof surface, creating what appears to be an extremely complex building.
The structure is supported on cast-in-place concrete tripods from which hollow-section steel beams extend at various angles to the peak of each roof area. Between the main steel members, the hyperbolic paraboloid surfaces are formed by a Triodetic grid system of aluminum tubes and nodes, formed of either equal-sided squares or pentagons, intersected with diagonals which carry the roof load in pure tension. This allowed members to be relatively small and light, helping to keep the overall roof sections as thin as possible. The Triodetic structure is topped by 2"x 6" cedar joists and tongue-and-groove cedar decking. The original cedar shingle roof surface was recently replaced with copper sheathing.