Mass timber construction in Canada is in the spotlight and emerging as a sustainable building system that offers an opportunity to optimize the value of every tree harvested and to revitalize a declining forest industry, while providing climate mitigation solutions. Little research has been conducted, however, to identify the mass timber research priorities of end users, barriers to adoption and engineering, procurement and construction challenges in Canada. This study helps bridge these gaps. The study also created an interactive, three-dimensional GIS map displaying mass timber projects across North America, as an attempt to offer a helpful tool to practitioners, researchers and students, and fill a gap in existing knowledge sharing. The study findings, based on a web-based survey of mass timber end users, suggest the need for more research on (a) total project cost comparisons with concrete and steel, (b) hybrid systems and (c) mass timber building construction methods and guidelines. The most important barriers for successful adoption are (a) misconceptions about mass timber with respect to fire and building longevity, (b) high and uncertain insurance premiums, (c) higher cost of mass timber products compared to concrete and steel, and (d) resistance to changing from concrete and steel. In terms of challenges: (a) building code compliance and regulations, (b) design permits and approvals, and (c) insufficient design experts in the market are rated by study participants as the most pressing “engineering” challenge. The top procurement challenges are (a) too few manufactures and suppliers, (b) long distance transportation, and (c) supply and demand gaps. The most important construction challenges are (a) inadequate skilled workforce, (b) inadequate specialized subcontractors, and (c) excessive moisture exposure during construction.
The Petawawa Research Forest (PRF) was established in 1918 and is the oldest research forest in Canada. It is located along Highway 17, east of Chalk River, Ontario, and is part of Garrison Petawawa under the jurisdiction of the Department of National Defence. By special agreement, it is managed by the Canadian Wood Fibre Centre, under the Canadian Forest Service, Natural Resources Canada. The research undertaken at the PRF influences forest policy, industry, silvicultural practices, and private forest management practices across the country. Operational commercial harvests also occur at the PRF.
Meridian Road is an access road at the PRF and leads to research, forest management, and recreational sites. A multi-cell culvert system at Young’s Creek recently failed (bottom left), and the crossing needed large-scale maintenance to allow the continued movement of logging trucks, vehicles, and research teams. The culvert failure negatively impacted water flow and habitat. To rectify these issues, a modern, single-lane engineered wood product (EWP) bridge, named Centennial Bridge (bottom right), was installed and built by Corington Engineering Inc., of Renfrew, Ontario. The experience at the PRF is of interest to sustainable forest licence (SFL) holders (and municipalities) looking to gain more knowledge about the construction and design of EWP access road bridges. The goal of this case study was to highlight the main construction and design details of Centennial Bridge and draw some comparisons to conventional steel-logging road bridges.
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.
Many strategies have been investigated seeking for efficiency in construction sector, since it has been pointed out as the largest consumer of raw materials worldwide and responsible of about 1/3 of the global CO2 emissions. While operational carbon has been strongly reduced due to building regulations, embodied carbon is becoming dominating. Resources and processes involved from material extraction to building erection should be carefully optimized aiming to reduce the emissions from the cradle to service. New advancements in timber engineering have shown the capabilities of this renewable and CO2 neutral material in multi-storey buildings. Since their erection is based on prefabrication, an accurate construction management is eased where variations and waste are sensible to be minimized. Through this paper, the factors constraining the use of wood as main material for multi-storey buildings will be explored and the potential benefits of using Lean Construction principles in the timber industry are highlighted aiming to achieve a standardized workflow from design to execution. Hence, a holistic approach towards industrialization is proposed from an integrated BIM model, through an optimized supply chain of off-site production, and to a precise aligned scheduled on-site assembly.