https://www.sciencenews.org/article/cro ... idges-safe
Data collected with cell phones moving across the Golden Gate Bridge rivaled the information that dedicated instruments could provide about the bridge’s structural integrity.
Accelerometers and GPS sensors that are standard components in smartphones collect information that can show how bridges flex and vibrate as vehicles travel across, researchers report November 3 in Communications Engineering.
Apps that gather the measurements could keep travelers safe by alerting engineers that a bridge needs repair. The tools could also warn of, or help prevent, catastrophic failures like the tragic footbridge collapse in the western Indian state of Gujarat on October 30, or the bridge span that crumbled in Pittsburgh in January (SN: 11/16/07).
“This is really applicable to any type of bridge,” says civil engineer Thomas Matarazzo of the U.S. Military Academy at West Point in New York. All you need, he says, is a way to get a smartphone on there — whether by car, in the pocket of a pedestrian or mounted to a scooter — and some way of monitoring the device (SN: 11/10/17).
Bridge failures, Matarazzo says, often come down to uncertainties about structural properties. “The only way to reduce those uncertainties is to monitor more frequently.” Crowdsourcing data from cell phones may be the best, and possibly only, way to get lots of data on bridges around the globe...
Cell phones could help monitor bridges that lack installed sensors, says Huili Wang, a civil engineer at the Dalian University of Technology in China who was not involved with the study. But he has doubts about the ultimate accuracy that smartphones can provide. Still, “it is a better approach for a rough estimate without [adding] more sensors,” he says.
Crowdsourced data probably won’t entirely replace dedicated sensors for monitoring bridges, Matarazzo agrees. But cell phones are unbeatable in a few ways, he says. “The advantage is in the convenience and the scale…. It’s a mobile-sensing system that’s already in place.”