Our own Mary Alexander featured in PEO’s January/February 2020 edition of the Engineering Dimensions Magazine!
In the profile titled, “This Engineer’s Dedication is Helping Evolve Ontario’s Building Techniques,” Structural engineer Mary Alexander, MEng, P.Eng., channels hard work into pioneering tall-wood structures in the province.
Alexander shares her early interest in structures, and the path that ultimately led to her becoming one of U of T’s top graduates, and the successful career at Moses Structural Engineers (a “close-knit family,” as Mary puts it).
Engineering Dimensions writes: Alexander has been able to develop a specialty, especially since the province’s 2015 amendment of the Ontario Building Code allows buildings of up to six storeys to be built out of principally wood. In fact, because of her expertise, Alexander co-authored the guide Ontario’s Tall Wood Building Reference with Moses Structural Engineering principal David Moses, PhD, P.Eng., and CHM Fire Consultants Ltd. for the Ministry of Natural Resources and Forestry. “In the [building] code, we can go only up to six storeys, but there’s nothing really stopping us from going over,” Alexander asserts.
“With tall timber (over six storeys), one example of mass timber is cross-laminated timber, which is made up of three, five, seven or nine layers of dimensional lumber that are laminated together. The layers alternate in direction, crisscrossing at 90 degrees. It improves the strength and stability of the member, since you get the strong axis of the wood situated in both directions.”
However, Alexander notes that there are limitations, such as stair shafts, which must be made of non-combustible materials; and elevator shafts, which in Ontario aren’t necessarily built from wood due to suppliers’ preference. (Wood is also more susceptible to shrink, presenting a challenge when building fire shafts, which, at six storeys, must be made from non-combustible materials.) Alexander also co-authored the 2017 Ontario Wood Bridge Reference Guide, again with Moses, along with other engineers from her firm and Brown & Co., a firm that specializes in bridges, including wood bridges, for the provincial Ministry of Natural Resources and Forestry and the Canadian Wood Council.
“When you see a wood bridge, it’s usually a pedestrian wood bridge in a park,” Alexander says. “But guess what? You can build a wood bridge for highways. It’s done all through Europe and BC and throughout the United States.” However, Alexander suspects that most Ontario engineers stick to manmade materials due to familiarity.
Her expertise in co-authoring the documents came from her background research in building tall wood buildings. Alexander has since incorporated into her work helping people who work with wood but don’t necessarily have experience working on taller structures. “You want to make it clear to read for somebody who’s worked with wood but hasn’t done a six-storey building,” she says. “I worked with [Local 27 Carpenters and Allied Workers, a trade union]…and put together a six-storey module to show them all the connections with wood.”
Alexander’s proudest moment, though, is working on the Brampton, ON, Saint Elias the Prophet Ukrainian Catholic Church restoration.
The original church burned in a fire, and Alexander engineered many of the structural elements, including the church’s five Boyko domes—the largest of which weighs over 18,000 kilograms—typical of Ukrainian-style architecture. “We used glulam,” Alexander explains. “[It’s] a dimensional wood lumber laminated together…because trees come only so big.”
On the outside, they used cedar. Alexander was filled with awe when she visited the site. “Everything was huge…I’m used to going on-site, where everything is dirty, but this site was very clean. You could smell the fresh-cut cedar lumber,” she reminisces. “It’s so nice that you forget that you’re supposed to be reviewing the installation. But it’s so stunning on the inside, and they kept with the tradition of the original church.” The church ultimately won the 2016 Wood Works! Institutional-Commercial Wood Design Award <$10 million. It’s projects like this that make Alexander, who is just finishing up a year-long parental leave, eager to get back to work.
