Some of the leading engineering companies in the world highlight advanced applications of timber in construction, ranging from a hybrid tower underway in Canada to greenhouse domes in China.
The Arbour (Toronto, Canada)
The Arbour is a ground breaking timber tower structure. Image credit: Moriyama & Teshima
The Arbour, is a new ten-story building for George Brown College in Toronto. It features a novel structural system consisting of the slab-band arrangement commonly used in concrete construction but replaces most of the concrete with mass timber. Composite CLT-concrete slab bands with an overall thickness of 15.5 inches span 30 feet between large 1.4-foot- by-3.9-foot timber columns, and infill 6-inch- thick CLT panels clear span 15.5 feet between the slab bands.
Central stair and elevator cores consisting of steel columns and diagonal bracing provide lateral resistance for the building. The end result is a primarily timber construction floor system that offers a thickness and flat soffit comparable to concrete construction but with a sharp reduction in both embodied carbon and construction time. The exposed timber flooded by ample daylight will also create a wonderful physical work environment for students and faculty.
NIR Centre, (Portland, America)
The NIR Center is a hybrid timber tower building. Image credit: Courtesy Holmes Structures
The NIR Center, a ten-story hybrid structure of mass plywood floor panels and steel delta-beams utilizing the new Type IV-B heavy timber building using a unique hybrid structure of mass timber floor cassettes and precast concrete beams and columns.
Taiyuan Botanical Garden (Shanxi province, China)
Some of the Botanical Dome structure components are 300 feet long. Image credit: Structurecraft
The Taiyuan Botanical Garden project comprises three domes functioning as greenhouses for exotic plants. In each dome, a slender timber lattice grid shell supports the glass-clad enclosures. The largest dome spans almost 300 feet, making it the longest clear-span timber grid shell of its type in the world.
The structural engineer and builder for these three timber grid shells, created a beautiful but efficient design, using the latest in parametric geometry and structural optimization techniques.
All three parabolic grid shells comprise double-curved glulam beams, arranged in two or three crossing layers. When viewed from above, the timber structures resemble seashells, with the primary members closely bunched on one side and then fanned out across the surface of the domes.
This complex geometrical arrangement means that every one of the members is unique. Digital fabrication techniques were key to realizing these structures, automatically generating the g-codes and assembly information for the more than 250,000 unique pieces and fasteners in them. The engineering team also carried out significant full-scale structural testing on the unique hidden connections used throughout the domes, working with a structural testing lab as well as Tongji University.
The District Office (Oregon, America)
The District Office features an exposed one-hour fire-resistant mass timber frame. Image credit: Hacker Architects
The District Office features an innovative optimized, fiber-count mass timber frame that utilizes a tight colonnade column layout in one direction with long-span glulam beams. Not only does it allow for a clean, fully exposed, one-hour fire-resistance-rated mass timber frame for maximum daylighting, but it also enables organized routing of MEP systems.
This is further developed by providing chases between CLT panels to allow for smaller distribution lines such as conduits and sprinklers. The building accommodates MEP routing through and/or over the girders coupled with a panelized CLT and glulam beam floor system. The speed of construction and fewer pieces to handle were key drivers on this fast-track project.
