mcCallumSather participated as part of an independent review panel, hired by ArcelorMittal Dofasco, to develop a case study for a hypothetical mid-rise, mixed-use commercial and residential building. The research involved a full Life Cycle Analysis, cost, and scheduling predictions, comparing the differences between wood, steel, and concrete structural systems.

“This analysis is very easy to integrate early in the design process. This allows us to choose the best performing and most cost-effective solutions right from the start. This analysis is not extraneous. It’s very important in making design decisions,” says Willems Ransom, Senior Design Architect on the project.

There was a lot of debate about the appropriate site conditions, construction techniques, and the parameters on which we would model the building. The priority was to have a study that developers could relate to and see as their own. The conclusion from the team was a 74,443 SF mixed-use structure and featured a split ground-level podium for commercial space separated by a pedestrian walkway and 75 residential units on the upper levels.

The research team included structural, electrical, mechanical engineers, scheduling, and cost consultants who reviewed the three different design scenarios. For the purposes of the study, only the structural elements of the core, upper levels, and roof were significantly altered.

“This case study was about designing one functionally equivalent building and seeing how the numbers fall under three different building options. Is there a tipping of the scales in terms of performance?” says Willems.

In terms of the total cost, the steel design was the most economical at $16 million. The concrete estimate was 2 per cent higher. Mass timber was even more so, coming in 19 per cent higher, driven mainly by increased material and installation costs for the upper floors. At 153 construction days total, the steel design was the fastest, beating wood by eight days and concrete by 20.

We also conducted LCA analysis which measured global warming potential, acidification, eutrophication, smog formation, ozone depletion, and primary energy demand. Overall Steel had the lowest potential for acidification, eutrophication, smog, and primary energy demand, performing well in terms of its ability to contribute to the reduction of global warming and ozone depletion. Wood performed well in terms of global warming potential, and smog formation, while concrete outperformed others in the ozone depletion potential.

The full study was recently published and can be found here.