The feasibility of manufacturing cross-laminated timber (CLT) from southern yellow pine (United States grown) treated with micronized copper azole type C (MCA-C) preservative was evaluated. Lumber (2x6 visually graded no. 2 boards) was treated to two retention levels (1.0 and 2.4 kg/m3 ), planed to a thickness of 35 mm, and assembled along with an untreated control group using three adhesive systems following product specifications: melamine formaldehyde (MF), resorcinol formaldehyde (RF), and one-component polyurethane (PUR). Block shear and delamination tests were conducted to examine the bonding performance in accordance with ASTM D905 and ASTM D2559 Standards, respectively. One-way analysis of variance and Kruskal-Wallis H test were conducted to evaluate the effects of preservative retention and adhesive type on block shear strength (BSS) and wood failure percentage (WFP). Regardless of adhesive type, the 1.0 kg/m3 retention treatment significantly lowered BSS compared to the untreated control. CLT composed of the laminations treated at 2.4 kg/m3 maintained BSS when PUR and RF were used but not MF. The average WFP of each CLT configuration ranged from 89% to 99%. The untreated CLT specimens did not experience any delamination under accelerated weathering cycles. The delamination rates of the treated specimens assembled using MF and RF increased with the preservative retention level, while PUR provided delamination rates less than 1% to the laminations treated at both levels. These combined data suggest that, under the conditions tested, PUR provided overall better bonding performance than MF and RF for MCA-C treated wood.
The CLT Handbook provides vital “How to” information on CLT for the design and construction community, and is a great source of information for regulatory authorities, fire services and others. The CLT Handbook is also a good textbook for university level timber engineering courses. In summary, the Canadian CLT Handbook will remain the most comprehensive reference for sharing the latest technical information on North American CLT.
The Canadian edition of the CLT Handbook, first published in 2011 under the Transformative Technologies Program of the Natural Resources Canada, played an imperative role in accelerating the use and acceptance of CLT in North America. Its introduction subsequently led to the publication of the US Edition. The Canadian Edition supported the early use of CLT products from Canadian manufacturers in many small to large projects across Canada and the US, and paved the way for CLT and other wood products to be used in new applications like tall and large buildings, and bridges.
Since then, additional research has taken place globally and substantial regulatory changes have occurred enabling more wood to be used in construction. Those developments highlighted a need for the CLT Handbook to be updated. The 2019 Edition of the CLT Handbook, for example, augments the recently developed CLT provisions in CSA Standard in Engineering Design in Wood and it includes a design example of an 8-storey CLT building. It helps expand the knowledge base of the designers about CLT enabling them to develop alternative solutions for taller and larger buildings that are beyond the boundaries of the acceptable solutions in building codes.
This monitoring study aims to generate field performance data from a highly energy efficient building in the west coast climate as part of FPInnovations’ efforts to assist the building sector in developing durable and energy efficient wood-based buildings. A six-storey mixed-use building, with five storeys of wood-frame residential construction on top of concrete commercial space was completed in early 2018 in the City of Vancouver. It was designed to meet the Passive House standard. The instrumentation aimed to gather field data related to the indoor environment, building envelope moisture performance, and vertical movement to address the most critical concerns among practitioners for such buildings.
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 aims to generate moisture performance data for several configurations of highly insulated woodframe walls meeting the RSI 3.85 (R22 eff) requirement for buildings up to six storeys in the City of Vancouver. The overarching goal is to identify and develop durable exterior wood-frame walls to assist in the design and construction of energy efficient buildings across the country. Wall panels, each measuring 1200 mm wide and 2400 mm tall, form portions of the exterior walls of a test hut located in the rear yard of the FPInnovations laboratory in Vancouver. Twelve wall panels in six types of wall assemblies are undergoing testing in this first phase. This report, first in a series on this study, documents the initial construction and instrumentation.