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.
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...
This study illustrates the range of possible wood construction approaches for school buildings that are up to four storeys in height. As land values continue to rise, particularly in higher-density urban environments, schools with smaller footprints will become increasingly more necessary to satisfy enrollment demands. There are currently a number of planned new school projects throughout British Columbia that anticipate requiring either three-or four-storey buildings, and it is forecasted that the demand for school buildings of this size will continue to rise.
This study is closely related to the report Risk Analysis and Alternative Solution for Three- and Four-Storey Schools of Mass Timber and/or Wood-Frame Construction prepared by GHL Consultants, which explores the building code related considerations of wood construction for school buildings that are up to four storeys in height. Though wood construction offers a viable structural material option for these buildings, the British Columbia Building Code (BCBC 2018) currently limits schools comprised of wood construction to a maximum of two storeys, while also imposing limits on the overall floor area. As such, the reader is referred to the GHL report for further information regarding building code compliance (with a particular emphasis on fire protection) for wood school buildings.
This project studied the feasibility and performance of a mass timber wall system based on
Nail Laminated Timber (NLT) for floor/wall applications, in order to quantify the effects
of various design parameters. Thirteen 2.4 m × 2.4 m shear walls were manufactured and
tested in this phase. Together with another five specimens tested before, a total eighteen
shear wall specimens and ten configurations were investigated. The design variables
included fastener type, sheathing thickness, number of sheathings, sheathing material,
nailing pattern, wall opening, and lumber orientation. The NLT walls were made of SprucePine-Fir (SPF) No. 2 2×4 (38 mm × 89 mm) lumber and Oriented Strand Lumber (OSB)
or plywood sheathing. They were tested under monotonic and reverse-cyclic loading
protocols, in accordance with ASTM E564-06 (2018) and ASTM E2126-19, respectively.
Compared to traditional wood stud walls, the best performing NLT based shear wall had
2.5 times the peak load and 2 times the stiffness at 0.5-1.5% drift, while retaining high
ductility. The advantage of these NLT-based wall was even greater under reverse-cyclic
loading due to the internal energy dissipation of NLT.
The wall with ring nails had higher stiffness than the one with smooth nails. But the
performance of ring nails deteriorated drastically under reverse-cyclic loading, leading to
a considerably lower capacity. Changing the sheathing thickness from 11 mm to 15 mm
improved the strength by 6% while having the same initial stiffness. Adding one more face
of sheathing increased the peak load and stiffness by at least 50%. The wall was also very
ductile as the load dropped less than 10% when the lateral displacement exceeded 150 mm.
The difference created by sheathing material was not significant if they were of the same
thickness. Reducing the nailing spacing by half led to a 40% increasing in the peak load
and stiffness. Having an opening of 25% of the area at the center, the lateral capacity and
stiffness reached 75% or more of the full wall.
A simplified method to estimate the lateral resistance of this mass timber wall system was
proposed. The estimate was close to the tested capacity and was on the conservative side.
Recommendations for design and manufacturing the system were also presented.
Currently the massive timber shear walls are mainly made from Cross Laminated Timber (CLT), which possesses a high in-plane shear strength and rigidity. But only part of its elements (mainly the vertically aligned laminae) are engaged in carrying the vertical load and that could be a limitation when designing taller timber structures or wherever higher...
This report provides an overview of major changes occurred in the recent decade to design and construction of the building envelope of wood and wood-hybrid construction. It also covers some new or unique considerations required to improve building envelope performance, due to evolutions of structural systems, architectural design, energy efficiency requirements, or use of new materials. It primarily aims to help practicioners better understand wood-based building envelope systems to improve design and construction practices. The information provided should also be useful to the wood industry to better understand the demands for wood products in the market place. Gaps in research are identified and summarized at the end of this report.
Overall moisture management during construction has become increasingly important due to the increase in building height and area, which potentially prolongs the exposure to inclement weather, and the overall increase in speed of construction, which may not allow adequate time for drying to occur. This report provides guidelines and relevant information about on-site moisture management practices that can be adapted to suit a range of wood construction projects...