INNOVATION July-August 2016

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The 18-storey cores were constructed before installation of the building's timber and envelope began in June 2016.

Construction Tolerances and Sequencing A carefully detailed structural system that accounts for construction tolerances can greatly reduce the risk of on-site issues causing delays and undue costs to the owner. All material interfaces were identified and evaluated with regards to their material standard tolerance compatibilities. Where required, the design details and project specifications were adjusted to overcome discrepancies. Additionally, quality- control requirements were outlined in the specifications for all CLT and glulam elements. In order to facilitate the use of one crane and provide sufficient time for manufacturing and shipping of the heavy timber elements, the construction team erected the concrete cores before the wood arrived onsite (Left). When the timber-and-envelope stage began, the team began installing 22 large pre-fabricated envelope segments at each level, in parallel with the timber. This sequencing ensures weather protection at each floor, allowing building fit-outs to begin immediately. Concept Mock-up To validate the proposed design’s constructability, the construction team constructed a full-scale mock-up of a portion of the building, 8 metres x 12 metres in plan and two storeys tall. The mock-up included several connection types to help determine and optimise the details used in the final design. In addition, the mock-up was used for development and evaluation of building-envelope systems considered for the project. Conclusion A mass timber building of this scale carries a unique set of engineering and management challenges, many of

which can be mitigated through the use of innovative design strategies and strong quality-control protocols. To date, the project's cost has been competitive with that of concrete towers in the local marketplace— largely due to an integrated design team, real-time input from trades, and structural discipline. v Duane Palibroda , P.Eng, Struct.Eng., is Managing Principal at Fast+Epp Structural Engineers, and contributes more than 25 years of experience as project leader on key projects. Bernhard Gafner , P.Eng, is an Associate at Fast+Epp Structural Engineers. He is project manager and design lead on the UBC project. Robert Jackson , EIT, is a project engineer at Fast+Epp Structural Engineers and is heavily involved in the design and construction of UBC Brock Commons.

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J U LY/AU G U S T 2 016

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