Concrete check-up: Fae Azhari develops diagnostics for critical infrastructure

Professor Fae Azhari (MIE, CivE) holds a sample of the self-sensing concrete she designed. Her work helps monitor the structural health of crucial infrastructure such as bridges, roads and hydroelectric dams. (Credit: Roberta Baker)

This story originally appeared on U of T Engineering News.

Canada will spend $125 billion on infrastructure maintenance and expansion in the next 10 years. Professor Fae Azhari (MIE, CivE) is helping stretch those dollars farther by keeping our buildings, bridges, roads and reservoirs safe and structurally sound for longer.

Azhari’s research focuses on structural health monitoring. Just as you visit the doctor for periodic check-ups, structures need their health checked too — but instead of blood tests and heart rate measurements, engineers usually perform visual inspections and spot-checks with sensors and instruments.

“The problem with visual inspections is that they’re pretty subjective, and with periodic monitoring, you can miss certain events or failures,” says Azhari. “Now we’re moving toward continuous monitoring by incorporating permanent sensors on important structures to get real-time data.”

Degradation or damage suffered between inspections can have catastrophic consequences. In June 2013, a rail bridge just outside of downtown Calgary partially collapsed as a train was passing over it. The train, carrying flammable and toxic liquids, derailed. Emergency measures were taken to prevent the railcars from falling into the Bow River, which was running high with summer floodwater. The Transportation Safety Board of Canada determined that floodwaters had eroded the soil around the bridge’s foundations, causing the collapse. This loss of sediment from around foundational supports is called scour.

“Believe it or not, this happens very often, especially in North America and some Asian countries,” says Azhari. “Scour is a huge problem.”

For her PhD research at the University of California, Davis, Azhari tackled scour from a new angle: she took commercially available sensors that measure dissolved oxygen, typically used for agriculture or biological applications, and used them for sensing scour. Azhari’s design was to attach a number of oxygen sensors at increasing depths along the buried length of the bridge pier. If the pier is properly buried, the dissolved oxygen levels detected by the sensors should be very low — but as scour erodes the sediments and exposes the sensors to flowing water, the dissolved oxygen levels rise. As scour progresses, more and more sensors become exposed, indicating how badly scour is threatening the bridge’s structural integrity.

She has also worked on concrete sensors, including a design that integrates conductive carbon fibers and nanotubes into concrete, making it a self-sensing material. Measuring the resistance across the material reveals the stresses and strains on it. “This technology is well-proven in the laboratory, but moving it to the field is a big challenge,” says Azhari.

As she builds her research enterprise, Azhari plans to collaborate across disciplines and with key partners who could benefit from her sensors, as well her analysis and insight into the data that comes from them. “Transportation infrastructure, utilities, dams, power plants, wind turbines — basically any engineering system — needs maintenance and monitoring,” she says.

“It’s very important to get these sensors from prototype to implementation, and I want to work on that.”

Heat, housing and health: Marianne Touchie and the complexity of multi-unit residential buildings

Professor Marianne Touchie (CivE, MIE) is working with Toronto Community Housing and The Atmospheric Fund to better understand how changes to energy use affect indoor environmental quality in multi-unit residential buildings. Toronto Public Health is collaborating to use their data to inform policy. (Photo: Kevin Soobrian)

Professor Marianne Touchie (CivE, MIE) is working with Toronto Community Housing and The Atmospheric Fund to better understand how changes to energy use affect indoor environmental quality in multi-unit residential buildings. Toronto Public Health is collaborating to use their data to inform policy. (Photo: Kevin Soobrian)

Professor Marianne Touchie (CivE, MIE) is working with Toronto Community Housing and The Atmospheric Fund to better understand how changes to energy use affect indoor environmental quality in multi-unit residential buildings. Toronto Public Health is collaborating to use their data to inform policy. (Photo: Kevin Soobrian)


This story originally appeared at U of T Engineering News

This story is a part of a  five-part #RisingStars series, highlighting the work of our early-career professors.

In cities from coast to coast, condominium towers are being constructed at an unprecedented rate, with 30,000 new units added in 2015 to the Toronto market alone. This is driven both by recent advances in the design, engineering and construction of tall buildings, and a stark increase in demand for these multi-unit residential buildings (MURBs). “More people are moving downtown,” says Professor Marianne Touchie (CivE, MIE). “There’s very limited space, so we need high-density housing options and MURBs provide that.”

With a background in building science, Touchie studies the relationships between energy efficiency and indoor environment quality parameters, such as thermal comfort, in these high-density buildings. In Toronto, one of the largest suppliers of MURBs is Toronto Community Housing Corporation (TCHC), which owns 50 million square feet of residential space and houses 110,000 residents. Many of these are older buildings without air conditioning.

“A lot of these buildings rely on ventilation through the building envelope, which is not terribly effective. At the same time, we need to reduce our energy consumption and energy use,” she says. “But reducing energy usage has implications for occupants, and that’s what I’m interested in studying.”

Touchie is currently collaborating with The Atmospheric Fund (formerly the Toronto Atmospheric Fund) on a large research project—one that she has been involved with since her role as their Building Research Manager from 2014 to 2015. She and her colleagues are collecting data on energy consumption, temperature, humidity and carbon dioxide concentration in more than 70 apartments spanning seven different TCHC buildings.

“It’s probably the most comprehensive MURB monitoring project in North America, if not the world,” says Touchie.

They are also working with Professor Jeffrey Siegel (CivE), who is examining concentrations of formaldehyde, particulate matter and, through a partnership with Health Canada, radon concentrations. Touchie says that collaborations, such as those with TCHC, The Atmospheric Fund and Siegel, are critical to creating a comprehensive picture of the MURBs she studies. “Buildings are so complex,” says Touchie. “I have training in one particular area, but I’m not an indoor air quality expert. When we make changes from an energy perspective to the ventilation system, or the heating and cooling system, it has an influence on the air quality. Working with other experts, like Professor Siegel, we can gather data on all sides.”

Touchie’s findings with The Atmospheric Fund and TCHC have drawn the interest of Toronto Public Health. The agency is interested in the health impact of extreme heat, and the study has found that these TCHC buildings are often overheated, especially in the summer.

“Extreme heat is a health problem, especially for the most vulnerable populations,” says Sarah Gingrich, a Health Policy Specialist at Toronto Public Health. Very young children, the elderly and people with illnesses or taking certain medications are most at risk. “This work is providing evidence that excessive heat is a problem in older apartment buildings in Toronto. The research is showing that although the temperature cools down at night outside, in these buildings it rises during the day and they stay hot all night long.”

Touchie and her collaborators are finding that a major culprit for the inefficient heating and cooling performance is uncontrolled air leakage. These leaks often occur around windows, doors, exhaust fans and elevator shafts. But inefficiencies aren’t just a building issue: she adds that “because people can do whatever they want in their own homes, like open and close their windows, MURBs combine the complexity of high-rise buildings with the occupant wild card,” which makes managing the indoor environment even trickier.

“The study provides valuable information on Toronto apartment buildings that will help to inform policy development,” says Toronto Public Health’s Gingrich. “It fills a very important gap by providing up-to-date data that highlights some of the challenges in this type of building, and points to potential solutions.”

Next, Touchie hopes to expand her research to newer condos, where data is even scarcer. “They’re going up so quickly, and we really have no information about the quality of the indoor environment or their energy performance,” she says. “I am very curious whether their energy consumption matches the performance level promised at the design stage.”