Building with steel at the RAIC Festival of Architecture
Steel is a high-performance material with high capacity and, Ali said, is also sustainable and helps maintain resilient construction in an era of severe weather events.
Steel in building construction is durable, with a long life span, highly ductile and seismic resistant. It is also made of noncombustible material, and "does not contribute to spread of fire, especially during construction."
Steel allow for innovative framing systems with low floor to floor heights, as well as large window areas. There is minimal onsite waste, and in winter construction steel can be built at a higher speed.
One example, Ali said, was a mid-rise where "steel beat concrete by more than $1 million." A comprehensive analysis was made of use of concrete vs. steel, and the cost estimate for steel construction was $2.7 million, while for concrete the coast was $3.6 million.
This is not a hard and fast set of facts for each project; there can be differences in regional supply and other factors, but steel is an option.
"Steel is the world's most sustainable building material," he said. Up to 93 per cent of content in steel construction is recycled, and over 80 million tons of steel are recycled every year in North America.
The carbon footprint of steel has been reduced by 47 per cent since 1990, he added.
CISC has developed six industry average Environmental Product Declarations (EPD) for painted and unpainted, hot rolled structural shapes, hollow structural sections, and plate.
Jordan, who is trained as both a structural engineer and architect, said she originally hails from Pittsburgh and assumed most construction involved steel until she emigrated to Canada.
One of the most iconic examples of B+H's work in steel, Jordan said, is the Toronto Dominion Centre in Toronto. She added the firm has gone back again and again to refresh the building since its inception in 1967.
Another project that emphasized steel's use with form was the revamp of the Rideau Centre in Ottawa. The building has a designated heritage façade, but using it steel it was possible to add new elements and create drainage and lighting, as well as support a new canopy element.
The Royal Ontario Museum (ROM) was another project where steel was part of the form of the built structure, both in the superstructure and interior structure. The building has several "nodes" coming from different angles, making for a very complex project.
"I didn't envy the contractors putting it together," Jordan said.
Once in place there is a "lattice-like" quality to the structure, before it was clad in nodes, Jordan said.
Steel can also be used for architectural expression, she said.
Mosaic Stadium in Regina, Sask. was built with twin steel canopy structures, which were not only used for aesthetics but also to block wind and funnel it away from the stadium. The canopy also acted as a natural armature for audio, video and lighting equipment.
The University of Windsor Centre for Engineering Innovation in Windsor, On. Used a curtain wall structure. They wanted to introduce a "light filled space" she said, which wrapped a classroom facility in glass.
Speed of construction is another factor in design, she said. A lab building in the University of Windsor had to be open in advance of the rest of the project, and using steel they were able to quickly get the labs operational, Jordan said.
360 Oakville Place, in Oakville, On. Was a "standard six storey office complex" but steel was the better choice in this case, she said. Floor to floor height had to be increased, which increased the building envelope, but it was determined that steel was a quicker and better solution than concrete. Custom steel components were also used in the design phase to articulate an entry.
May 24, 2017