FPInnovations conducted a research project to study the construction of mid-rise wood exit shafts in Ontario and Québec. The scope of the project included an investigation into the concerns that have been raised in regards to the use of wood exits in mid-rise buildings, an analysis of recent Canadian fire statistics in residential multi-family structures, and a fire demonstration of a mass timber wall and supported light-frame floor. This report describes the fire demonstration completed as part of this project; this report acts as a supplement to the full project report.
FPInnovations initiated this project to demonstrate the ability of wood exit stairs in mid-rise buildings to perform adequately in a fire when NBCC requirements are followed, with the intent of changing perceptions of the fire safety of wood construction. The objective of this research is to investigate further the fire safety afforded by exit stair shafts of combustible construction, with the ultimate objective of better consistency between the provincial and national building codes with respect to fire requirements for exit stair shafts in mid-rise wood-frame construction.
A full-scale demonstration fire was conducted at National Research Council Canada (NRCC) to show that a 2-hr non-standard severe design fire in an apartment would have little or no effect on an adjacent elevator or stair shaft. The test was performed to support the approval of an alternative solution for a deemed-to-satisfy 2-hr noncombustible construction assembly, intended for the construction of a tall wood building in Quebec City (Canada). Throughout the duration of the fire no impact was observed in the CLT shaft: there was no evidence of temperature rise and no apparent smoke leakage. This suggests there was little to no effect of the design fire on the structure of the CLT shaft itself.
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.
A full-scale demonstration dire was conducted at National Research Council Canada to show how a mass timber vertical shaft could withstand a severe fire exposure lasting at least two hours. The fire resistance tests and the demonstration fire were performed to support the approval and construction of a tall wood building in Quebec city; the building is planned to be 13 storeys which includes a 12-storey wood structure above a 1-storey concrete podium. An updated calculation methologody to determine the fire resistance of CLT is provided in Capter 8 (Fire) of the CLT Handbook.
The consortium of Nordic Wood Structures, EBC and Yvan Blouin Architect are designing a 13- storey residential building using a mass timber structure. The project, named "Origine" is proposed to be located in the eco-neighbourhood of Pointe-aux- Lièvres in Quebec City and to start construction in spring 2015. The mass timber structure would be composed primarily of glue-laminated timber and crosslaminated timber (CLT). The cross-laminated timber consists of at least three orthogonally bonded layers of solid-sawn lumber that are laminated by gluing of longitudinal and transverse layers with structural adhesives to form a solid rectangular-shaped, straight and plane timber intended for floor, roof or wall applications. The National Research Council Canada (NRC) was requested to assist in the demonstration of an alternative solution to noncombustible construction as prescribed in the Québec Construction Code [1] and the National Building Code of Canada (NBCC) [2]. Three series of fire tests were conducted at NRC to investigate: the fire endurance (fire resistance) of CLT floor and wall assemblies [3], the fire performance of a CLT exterior wall assembly [4], and the fire demonstration of a CLT stair/elevator shaft for the proposed building. This report provides the description and results of the fire demonstration for the CLT stair/elevator shaft. This fire demonstration was funded by the Government of Quebec’s Ministère des Forêts, de la Faune et des Parcs through FPInnovations.
This thesis discusses the results of experimental tests on two post-tensioned timber core-walls, tested under bi-directional quasi-static seismic loading. The half-scale two-storey test specimens included a stair with half-flight landings. Multi-storey timber structures are becoming increasingly desirable for architects and building owners due to their aesthetic and environmental benefits. In addition, there is increasing public pressure to have low damage structural systems with minimal business interruption after a moderate to severe seismic event. Timber has been used extensively for low-rise residential structures in the past, but has been utilised much less for multi-storey structures, traditionally limited to residential type building layouts which use light timber framing and include many walls to form a lateral load resisting system. This is undesirable for multi-storey commercial buildings which need large open spaces providing building owners with versatility in their desired floor plan. The use of Cross-Laminated Timber (CLT) panels for multi-storey timber buildings is gaining popularity throughout the world, especially for residential construction. Previous experimental testing has been done on the in-plane behaviour of single and coupled post-tensioned timber walls at the University of Canterbury and elsewhere. However, there has been very little research done on the 3D behaviour of timber walls that are orthogonal to each other and no research to date into post-tensioned CLT walls. The “high seismic option” consisted of full height post-tensioned CLT walls coupled with energy dissipating U-shaped Flexural Plates (UFPs) attached at the vertical joints between coupled wall panels and between wall panels and the steel corner columns. An alternative “low seismic option” consisted of post-tensioned CLT panels connected by screws, to provide a semi-rigid connection, allowing relative movement between the panels, producing some level of frictional energy dissipation.
New Zealand Society for Earthquake Engineering Conference
Research Status
Complete
Notes
April 26-28, 2013, Wellington, New Zealand
Summary
This paper describes options for seismic design of pre-fabricated timber core-wall
systems, used as stairwells and lift shafts for lateral load resistance in multi-storey timber
buildings. The use of Cross-Laminated Timber (CLT) panels for multi-storey timber buildings is
gaining popularity throughout the world, especially for residential construction. This
paper describes the possible use of CLT core-walls for seismic resistance in open-plan
commercial office buildings in New Zealand. Previous experimental testing at the
University of Canterbury has been done on the in-plane behaviour of single and coupled
Pres-Lam post-tensioned timber walls. However there has been very little research done
on the behaviour of timber walls that are orthogonal to each other and no research into
CLT walls in the post-tensioned Pres-Lam system. This paper describes the proposed test regime and design detailing of two half-scale twostorey CLT stairwells to be tested under a bi-directional quasi-static loading. The test specimens will include a half-flight stair case with landings within the stairwell. The “High seismic option” consists of post-tensioned CLT walls coupled with energy dissipating U-shaped Flexural Plates (UFP) attached between wall panels and square hollow section steel columns at the corner junctions. An alternative “Low seismic option” uses the same post-tensioned CLT panels, with no corner columns or UFPs. The panels will be connected by screws to provide a semi-rigid connection, allowing relative
movement between the panels producing some level of energy dissipation.
