Canada’s first ‘supertall’ building engineered with ArcelorMittal’s HISTAR® A913 steel
ArcelorMittal’s HISTAR® A913 steel has played a central role in the development of Canada’s first ‘supertall’ skyscraper.
Located in Bloor Street West in Toronto, Canada, One Bloor West stands at one of the country’s most prominent intersections, near Toronto’s busiest subway station. For these reasons, the building’s original design brief called for an exceptional retail space free of columns within it and at the corners, to capitalise on the high-traffic location. The development team envisioned creating Canada’s tallest building to complement this important site.
The distinctive structure is an outstanding addition to Toronto’s skyline, elevating the city’s architectural portfolio. This supertall building (defined as more than 300m high) is primarily a residential tower, but it also incorporates hotel levels above premium retail and event spaces.
Composite mega columns
The final structural design features an 85-storey square tower optimised to reduce wind loads. While most towers in Toronto use conventional concrete systems, including slabs and central cores, One Bloor West’s design transfers loads above the retail levels to large, inclined steel struts resting on ‘composite mega columns’ composed of concrete and steel at the ground level. This eliminates the need for interior columns or a concrete core in the retail space.
ArcelorMittal’s HISTAR® A913 steel satisfied the strength requirements, and the lighter section sizes also reduced the loads on the crane. This grade is a high-strength, low-alloy steel widely used in tall building construction for its excellent mechanical properties and economic benefits. Its exceptional yield strength (the maximum stress that can be applied before it permanently deforms) combined with high ductility (the degree to which it can be strained before fracturing) allows for thinner and lighter structural elements without compromising safety or performance. This reduces material use and increases efficiency.
Additionally, HISTAR®’s unique production process ensures consistent quality and better weldability, making it ideal for complex designs such as composite mega columns.
One Bloor West exemplifies what can be achieved when strong engineering design supports and complements bold architecture rooted in a philosophy of form following function.
