Introduction
This project aims to demonstrate the advantages of mechanically stress rated balsam fir (MSR) for wood construction. It is part of an innovative approach to optimize the design and performance of structures while promoting local species. The project is funded by the Québec Ministry of Natural Resources and Forestry as part of its call for research and development projects in wood construction.
A major advantage of balsam fir is its dimensional stability, which is superior to other species in the spruce-pine-fir group. This property reduces the risk of warping, which is essential for the manufacture of prefabricated products where precision and consistency are essential, particularly in automated processes.
Design and study building
The firm “L2C Experts-conseils en structure” designed a six-storey residential building incorporating the mechanical properties of MSR 1500Fb-1.4E wood in a section of walls. This building, located in Quebec City as part of the KOS project, includes 70 units and was constructed with prefabricated walls by Ultratec. To compare performance, twin walls made of conventional wood (SPF No. 2) were also manufactured. The MSR 1500Fb-1.4E balsam fir wood was supplied by Groupe de scieries GDS.
Monitoring and instrumentation
A real-time monitoring program analyzes the dimensional behaviour of the walls in service, including shrinkage, warping, and settlement. Temperature and humidity sensors and potentiometers were installed to collect this data.
Testing and performance
Mechanical tests on MSR wood beams confirmed the consistency between theoretical and measured values, validating the reliability of this class for structural applications. The project also evaluates efficiency gains on automated and manual production lines to measure the impact of improved dimensional stability on prefabrication. Initial results show that MSR walls were assembled without any rejects, proving their suitability for automated processes.
Significance and impact
Beyond the technical aspects, the project examines the economic and environmental benefits. The plans for the twin buildings allow for a comparison of the quantity of materials, costs, and carbon footprint between an optimized structure and a conventional structure. A market study is underway to identify the conditions for successful commercialization of MSR wood, in line with the needs of the industrialized construction sector.
This project marks a key step in promoting local species and innovation in wood construction. It paves the way for more efficient, sustainable buildings that are suited to prefabrication processes.
