The Strathcona Music Building at McGill University underwent structural strengthening using advanced FRCM (fibre-reinforced cementitious matrix) systems. This structural strengthening project preserved the iconic Victorian-era landmark while enhancing its durability for future generations.
To the casual observer, the Strathcona Music Building is a sturdy landmark anchoring the eastern flank of McGill University’s Montreal campus. Like the grim-faced statue of Queen Victoria peering out from the entrance’s front steps, the building has kept calm and carried on over 120 years of Montreal winters, its façade routinely adorned with large icicles hanging unflinchingly from its many ledges.
Built in 1896, the imposing gray limestone edifice – originally named the Royal Victoria College for girls by Lord Strathcona – was last renovated in 1971, when it was given to McGill University. The building was then rechristened with its present name and became home to the university’s Schulich School of Music and Pollack Hall. Today, it stands as one of the busiest cultural venues in the city, holding some 700 concerts and other events annually.
“Masonry was sometimes used as structural elements,” explained Mapei Canada Inc.’s Engineering and Architectural sales representative Hamza Ouziame. Upon surveying the Strathcona’s interior walls in the spring of 2022, Ouziame and Luca Albertario, Mapei Group’s Regional Product Line Manager for the Building line, found that the walls were composed of terracotta bricks dating from the 19th century.
These walls would certainly require extra strengthening to maintain their structural integrity. “The engineers were looking for a fiber-reinforced polymer [FRP] solution and were happily surprised to find Mapei has a fiber-reinforced cementitious matrix [FRCM] option designed for masonry,” Ouziame said. This option was a perfect fit for the job at hand.
The FRCM based structural strengthening system used in this project is centered on MAPEGRID G 220 alkali-resistant, glass fibre mesh that is applied with PLANITOP HDM MAXI fibre-reinforced mortar.
A complete structural strengthening system
The FRCM system for structural strengthening is centered on MAPEGRID G 220, an alkali-resistant, glass fibre mesh that is applied with PLANITOP HDM MAXI pozzolan-reaction, fibre-reinforced mortar.
When applied on masonry structures, MAPEGRID G 220 makes up for the structure’s lack of tensile strength and increases the structure’s overall ductility so that stresses are distributed more evenly. The system adheres perfectly to the substrate; the system’s mechanical properties are such that localized stresses always provoke a failure in the substrate rather than at the substrate/strengthening-system interface.
“MAPEGRID G 220 is the main product, but it requires a matrix,” Ouziame explained. “PLANITOP HDM MAXI mortar is compatible with masonry. Unlike a polymer-modified mortar, it allows breathability. It doesn’t have a low modulus of elasticity, and together with its moderate compressive strength, the products combine to work better with masonry than a FRP system. MAPEWRAP C FIOCCO carbon fiber cord is added to assist the long-term bond of the system for the interior.”
MAPEWRAP C FIOCCO carbon fiber cord was added to the chosen FRCM system to assist the long-term bond of the system for the interior.
Following the engineering team’s assessment, damaged bricks were identified that had to be replaced and repointed, after which MAPEI STEEL DRY 316 helical stainless-steel bars were inserted for local reinforcement. “Repointing can speak to replacement of a brick or a joint and changing out parts of the substrate that were at the point of failure,” Ouziame said. Workers also cleaned the bricks to remove efflorescence and dirt. PLANITOP 23** fiber-reinforced cementitious repair mortar, which is manufactured and distributed on the Canadian market by Mapei Canada Inc., was then used to smooth the wall surface in specified areas.
ELASTOCOLOR PRIMER WB, a water-based acrylic primer, was applied to saturate the masonry in preparation for the FRCM application. Once the first layer of PLANITOP HDM MAXI was applied, the MAPEGRID G 220 structural mesh was added with a 15-cm overlap between the bands, followed by a second layer of PLANITOP HDM MAXI. Then, a second and final layer of MAPEGRID G 220 mesh was added with the same overlap, followed by a third and final layer of PLANITOP HDM MAXI. Each layer of PLANITOP HDM MAXI was at 5-6 mm thickness.
A few products for buildings, again distributed by Mapei Canada Inc on the Canadian market (MAPECEM 100**, MAPECEM QUICKPATCH**, PLANITOP 25**), were also used to level and patch the floor slab where required.
The strengthening system involved applying MAPEWRAP C FIOCCO carbon fibre cords spread out in a 360-degree star formation.
Using the same FRCM system, the strengthened walls were then connected to leveled slabs for structural continuity. The final stage of the strengthening started by marking insertion points for 10 mm MAPEWRAP C FIOCCO carbon fibre cords as anchoring rope, about 1 m apart. Holes were drilled at each of these spots and filled with MAPEWRAP 12 moisture-tolerant, structural epoxy putty. Meanwhile, the anchoring ropes were impregnated with MAPEWRAP 21 epoxy resin and broadcast with MAPESAND COARSE** sand before insertion.
MAPEWRAP 12 was also applied around the inserted MAPEWRAP C FIOCCO carbon fibre cords as they were spread out in a 360-degree star formation. Finally, MAPEWRAP 21 was used to encapsulate the system fabrics by incorporating the wet-layup technique to saturate and encapsulate the fiber fabrics by way of mechanical saturation and to cure to a high-performance laminate. Once strength to the structural elements, thereby completing rehabilitation of the building envelope.
The Strathcona Music Building has seen the waning days of Queen Victoria’s reign and made it all the way through the 70-year reign of Queen Elizabeth II. It is certainly a tribute to history that this landmark institution is now poised to carry on its own legacy well into the future.
**These products are manufactured and distributed by Mapei Canada Inc on the Canadian market.
McGill University’s Strathcona Music Building, Montreal (Quebec, Canada)
Owner: McGill University
Year of construction: 1896
Main contractor: Atwill-Morin
Intervention by Mapei: supplying products for structural strengthening and concrete repair
Year of the Mapei intervention: 2022
Mapei coordinators: Hamza Ouziame, Michel Lafortune, and Baltazar Basabe (Mapei Canada Inc.); Luca Albertario (Mapei SpA, Italy)
Structural engineer: Elizabeth Darveau (WSP)
Photos: Ralph Thompson
