Timber building construction has been traditionally utilized to reduce inertial demands in high seismic regions. Applications in the United States however, are often limited to low-rise buildings of light-wood construction with distributed load bearing shear walls. Recent advancements in timber technologies are pushing mass timber systems into larger commercial scale markets where steel and concrete systems dominate the landscape. In high seismic regions, mass timber buildings currently lack code-defined lateral force resisting systems. This paper presents a new lateral force resisting system concept, known as the Heavy Timber Buckling-Restrained Braced Frame. The system is conceived, although not limited, for application in mid and high-rise building timber construction, and is inspired by the unbonded steel brace technology today widely spread throughout Japan and the United States. In order to qualify the system for future implementation in building codes, the paper presents results from proof-of-concept component testing of a brace consisting of a steel core and a mechanically laminated glulam casing acting as the bucklingrestraint mechanism. As well, findings from a study for implementation at the building system level is provided in order to assess overall system performance, constructability, and detailing.
The work presented in this report is a continuation of the FPInnovations' research project on determining the performance of the CLT as a structural system under lateral loads. A two storey full-scale model of a CLT house was tested under quasi-static monotonic and cyclic lateral loading in two directions, one direction at a time. In total five tests were performed; one push-over and two cyclic tests were conducted in the longer symmetrical direction (E-W), and two cyclic tests were performed in the shorter asymmetrical direction (N-S). In addition, before and after each test, natural frequencies of the house in both directions were measured. The main objective of the tests was to investigate 3-D system behaviour of the CLT structure subjected to lateral loads. The CLT structure subjected to lateral loads performed according to the design objectives.
As 6-storey wood-frame, massive-timber and hybrid wood buildings are increasingly accepted by more jurisdictions across Canada, there is a need to develop reliable elevator shaft designs that meet the minimum structural, fire, and sound requirements in building codes. Elevator shaft walls constructed with wood-based materials have the advantages of material compatibility, use of sustainable materials, and ease of construction.
In this exploratory study, selected elevator shaft wall designs built with nail-laminated-timber (NLT) structural elements were tested to investigate their sound insulation performance because little is known about the sound insulation performance of such wall assemblies. The tests were carried out in an acoustic mock-up facility in accordance to standard requirements, and provide preliminary data on the sound insulation performance of elevator shaft walls built with NLT panels.
Four different elevator shaft walls built with NLT panels were tested and their measured apparent sound insulation class (ASTC) ratings ranged from 18 to 39 depending on their construction details. Some of the reasons that may have contributed to the ASTC ratings obtained for the elevator shaft walls described in this report as well as recommendations for future designs were provided.
It is recommended to continue improving the sound insulation of elevator shaft walls built with NLT panels to meet or exceed the minimum requirements in building codes.
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