By Kayt Sukel
London’s skyline is undergoing radical change. With the need for more housing and office space, New London Architecture’s London Tall Buildings Survey 2026 notes that there are active plans to build 583 buildings of 20 stories or more over the next decade — more than doubling the number of tall buildings constructed in the past 10 years. With this influx of new construction, there is an emerging need for more structural health monitoring across the city. Yet, as noted in the recent article “London to transform into a metropolis among the clouds: an extensive need for SHM experts,” published by the British Institute of Non-Destructive Testing, the country faces a lack of qualified structural health monitoring experts.
Addressing the gap, argues Parsa Ghannadi, a research scientist at Iran’s Islamic Azad University, could be as simple as reaching for a mobile phone. Or maybe a few thousand.
Every day, millions of people traverse the city of London, and a large percentage of them carry a smartphone. As they walk city streets, travel on the Tube (London’s underground rail system), cross bridges, ride elevators, or climb stairwells, the devices in their pockets could easily collect much-needed data to monitor the structural integrity of not just London’s newest high rises, but also the other pieces of infrastructure surrounding them. That “crowdsensed” data could help engineers detect damage, support preventive maintenance, and extend the life of buildings — better ensuring public safety.
As a result, researchers from all over the globe, including Ghannadi, are asking a simple question: Is there a way to transform the sensors already embedded in smartphones and wearables to create a more scalable, affordable, and continuous structural health monitoring network in urban environments?
Structural health monitoring today
The combination of aging materials, environmental exposures, and constant physical loads takes its toll on built structures. Historically, the structural health of a building, bridge, road, tunnel, or other piece of infrastructure would be assessed by routine, time-based visual inspections performed by trained inspectors, said Simon Laflamme, Ph.D., M.ASCE, a researcher at Iowa State University’s Department of Civil, Construction, and Environmental Engineering. Then, if any issues — current or potential — are discovered, further analysis with specialized sensors and equipment can be performed.
“We need to have a general idea of what could be wrong and then develop a monitoring system around that,” Laflamme said. “It’s complex, and because of that, not many systems are consistently monitored ... . There’s not a single solution that can monitor for all the problems for a single (building).”
Developing a bespoke monitoring system requires careful design and — far too often — specialized and expensive sensors and hardware. Ghannadi stated that these sensors and hardware must be professionally installed, and they require expert teams to maintain them. Those costs can add up quickly.
“Our main problem is figuring out how to monitor many tall buildings cheaply and continuously without requiring large budgets or extensive expertise,” Ghannadi said. That’s where smartphones come in. “Ordinary citizens can easily help collect vibration data, making monitoring low cost, scalable, and community based.”
How crowdsensing works
Experts in public health and emergency preparedness have shown* that crowdsensing, or the act of collecting aggregate data from people’s smartphones, can help them conduct rapid assessments. The combination of targeted geographic coverage, real-time data collection, and subjective, on-the-ground observations can help identify potential disease outbreaks or give on-the-ground damage estimates. Susu Xu, Ph.D., an assistant professor at Johns Hopkins University’s Department of Civil and Systems Engineering, said those same characteristics make crowdsensing ideal for any kind of urban monitoring — including structural health monitoring.
“As people move around the city, they can collect data all the time,” Xu said. “This is a very powerful tool to monitor what’s happening in cities.”
Most smartphones contain microelectromechanical sensors called accelerometers, which measure changes in speed, tilt, and physical movement — and, consequently, vibrations. When a building is constructed, structural engineers will take a baseline measurement of the structure’s vibrations. Laflamme said crowdsensing could provide the data to see whether that baseline state has changed over time. “If we see that the vibration signature changes significantly, we then know something could be wrong,” he said.
Gathering that kind of vibration data through a crowdsensing network could be as easy as getting volunteers to download a ready-to-run script and then collecting a few minutes of acceleration data from a fixed location. Their phones can then send those data to a platform via Wi-Fi, where the data can be aggregated, filtered, and analyzed to look for patterns that indicate seismic damage, cracks, or defects that may reduce a structure’s stiffness.
“Engineers can use acceleration data to establish vibration-based structural health monitoring systems,” said Ghannadi. “Almost every floor in a tall building has several residents, and each resident has a smartphone, so we get numerous free sensors on every floor without buying or installing special equipment.”
What’s required for scale
The idea is a sound one, and many research laboratories are exploring ways to leverage crowdsensing for different applications besides human health. But before such structural health monitoring networks can be scaled up for a city the size of London, engineers will have to address several limitations — the first being recruiting people willing to participate.
“The biggest obstacle is getting enough people to take part regularly and correctly,” said Ghannadi. “The whole idea depends on volunteers. They must place their phones in the same fixed locations, run the same script, and keep doing it over time. Most people are busy and not trained in engineering, so motivating them and making the process extremely simple is hard.”
There is also the matter of data quality. People carry different types of smartphones, with different sensors embedded in them. Where those people prefer to carry their phones, at what locations they are taking data, and other factors could also influence the quality of the data.
“We need to be able to do some preprocessing to align the data and eliminate the low-quality data points,” Xu said. She added that engineers are working on rating the quality of different devices for different crowdsensing applications, but engineers will need to validate their results.
Still, Laflamme believes that crowdsensing is a “futuristic” approach for structural health monitoring that is worth exploring. There are so many different sensors in a phone that measure different physical phenomena. While those sensors are not as accurate as the more expensive options specifically designed for structural health monitoring, the phone-based options are improving every day.
“There’s a lot of potential here,” said Laflamme. “But for this approach to be feasible, it all has to go back to good engineering principles. You need to understand what you want to monitor and then design your solution to get the data you need no matter where it may be coming from.”
* “Use of Mobile Crowdsensing in Disaster Management: A Systematic Review, Challenges, and Open Issues” by Didem Cicek and Burak Kantarci of the School of Electrical Engineering and Computer Science at the University of Ottawa in Ottawa, Ontario, Canada, and “CrowdEIM: Crowdsourcing Emergency Information Management Tasks to Mobile Social Media Users” by Hongzhou Shen, Junpeng Shi, and Yihan Zhang of the School of Management, Nanjing University of Posts and Telecommunications, in Nanjing, Jiangsu, China
Kayt Sukel is a science and technology writer based in Overland Park, Kansas.
This article first appeared in the November/December 2026 issue of Civil Engineering as “Crowdsensing to Promote Urban Structural Health.”
