Featured Research

from universities, journals, and other organizations

Averting bridge disasters: New technology could save hundreds of lives

Date:
July 30, 2011
Source:
University of Maryland
Summary:
Millions of US drivers cross faulty or obsolete bridges every day, highway statistics show, but it's too costly to fix these spans or adequately monitor their safety, says a researcher who's developed a new, affordable early warning system. This wireless technology could avert the kind of fatal disaster along Minneapolis' I-35W on Aug. 1, 2007, he says -- and do so at one-one-hundredth the cost of current wired systems.

"If this kind of technology had been available in Minnesota four years ago, there's a good chance the fatal bridge collapse could have been avoided," the UMD researcher says.
Credit: MDOT

Millions of U.S. drivers cross faulty or obsolete bridges every day, highway statistics show, but it's too costly to fix all these spans or adequately monitor their safety, says a University of Maryland researcher who's developed a new, affordable early warning system.

This wireless technology could avert the kind of bridge collapse that killed 13 and injured 145 along Minneapolis' I-35W on Aug. 1, 2007, he says -- and do so at one-one-hundredth the cost of current wired systems.

"Potentially hundreds of lives could be saved," says University of Maryland electrical engineering researcher Mehdi Kalantari. "One of every four U.S. highway bridges has known structural problems or exceeded its intended life-span. Most only get inspected once every one or two years. That's a bad mix."

Kalantari has created tiny wireless sensors that monitor and transmit minute-by-minute data on a bridge's structural integrity. A central computer analyzes the data and instantly warns officials of possible trouble. He plans to scale-up manufacture in the fall.

"If this kind of technology had been available in Minnesota four years ago, there's a good chance the fatal bridge collapse could have been avoided," Kalantari adds. "This new approach makes preventive maintenance affordable -- even at a time when budgets are tight. Officials will be able to catch problems early and will have weeks or month to fix a problem."

More than one-in-four U.S. bridges are either structurally deficient or functionally obsolete, according to a 2009 estimate by the U.S. Society of Civil Engineers.

  • 72,000-plus U.S. bridges are listed by the U.S. Department of Transportation as "structurally deficient" and require extra surveillance.
  • 79,000 others are functionally obsolete, exceeding their life-span and carrying loads greater than they were designed to handle.

Kalantari's sensors measure indicators of a bridge's structural health, such as strain, vibration, flexibility, and development of metal cracks. The sensors are small, wireless, rugged, and require practically no maintenance, he says. They are expected to last more than a decade, with each costing about $20. An average-sized highway bridge would need about 500 sensors for a total cost of about $10,000.

"The immediacy, low cost, low energy and compact size add up to a revolution in bridge safety monitoring, providing a heightened level of early-warning capability," Kalantari concludes.

Newer "smart" bridges, including the I-35W replacement in Minneapolis, have embedded wired networks of sensors. But Kalantari says the cost is too high for use on older spans.

"A wired network approach will cost at least 100 times more than a wireless alternative, and that's simply unaffordable given the strain on local, state, and federal budgets," Kalantari estimates.

Current federal requirements call for an on-site, visual inspection of highway bridges once every two to five years, depending the span's condition. Bridges deemed structurally deficient must be inspected once each year.

In its report on the fatal Minneapolis bridge collapse, the National Transportation Safety Board identified a faulty "gusset plate" -- a connector essential to the bridge's structural integrity -- as a likely cause of the disaster.

The report notes an "inadequate use of technologies for accurately assessing the condition of gusset plates on deck truss bridges." Kalantari expects his technology to fill that need.

Testing of Maryland bridges

For almost a year, Kalantari has been testing his device in conjunction with the Maryland Department of Transportation, measuring the structural parameters of highway bridges in a real setting. This has enabled him to optimize the device's performance and energy consumption. His updated model is smaller and ten times more energy efficient than its predecessor.

The testing allows him to track the bridge's response to changes in weather conditions and traffic. For example, he's measuring how the metal expands and contracts as the temperature rises and falls. Also, he can compare the metal's response during periods of peak and light loads. He hopes to expand the field testing more broadly in Maryland and to deploy sensors fully across the spans.

  • Capital Beltway (I-495), Northwest Branch Bridge: Since August 2010, Kalantari has had eight sensors on the Northwest Branch Bridge, a truss span like the one that collapsed in Minneapolis, though smaller. The bridge has proven "safe" in all his tests, so far. "Everything is working the way it's supposed to -- both the bridge and my instruments," he reports.
  • Frederick, Maryland (I-70), Conococheague Creek Bridge: This span is the second provided by Maryland highway officials for Kalantari's test.

How the system works

As with conventional technology, the sensors measure variables reflecting the structural integrity of a bridge, such as strain, vibration, tilt, acceleration, deformation and cracking.

Serious problems are more obvious and easier to interpret, and so trip an alarm very quickly. Early-stage problems are more subtle, and it may take up to a few days until the system is confident enough to report a structural integrity issue.

The sensors are less than five millimeters thick and have four thin, flexible layers. The first senses and measures structural parameters; the second stores energy; the third communicates data; and the outer layer harvests energy from ambient light and ambient radio waves.

Kalantari says the sensors offer a significant improvement on existing technology:

  • No wires, batteries, or dedicated external power source;
  • Almost no maintenance;
  • Low cost;
  • Easy and quick to install;
  • Suitable for new and existing bridges.

Timetable

Kalantari says he's working in an "emerging market with no widely accepted commercial solution now available." To commercialize his technology, he founded Resensys LLC, a start-up in the University of Maryland's Technology Advancement Program incubator. He expects to scale-up production in September.


Story Source:

The above story is based on materials provided by University of Maryland. Note: Materials may be edited for content and length.


Cite This Page:

University of Maryland. "Averting bridge disasters: New technology could save hundreds of lives." ScienceDaily. ScienceDaily, 30 July 2011. <www.sciencedaily.com/releases/2011/07/110729175338.htm>.
University of Maryland. (2011, July 30). Averting bridge disasters: New technology could save hundreds of lives. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2011/07/110729175338.htm
University of Maryland. "Averting bridge disasters: New technology could save hundreds of lives." ScienceDaily. www.sciencedaily.com/releases/2011/07/110729175338.htm (accessed October 22, 2014).

Share This



More Matter & Energy News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com
Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Thanks, Marty McFly! Hoverboards Could Be Coming In 2015

Newsy (Oct. 21, 2014) If you've ever watched "Back to the Future Part II" and wanted to get your hands on a hoverboard, well, you might soon be in luck. Video provided by Newsy
Powered by NewsLook.com
Robots to Fly Planes Where Humans Can't

Robots to Fly Planes Where Humans Can't

Reuters - Innovations Video Online (Oct. 21, 2014) Researchers in South Korea are developing a robotic pilot that could potentially replace humans in the cockpit. Unlike drones and autopilot programs which are configured for specific aircraft, the robots' humanoid design will allow it to fly any type of plane with no additional sensors. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Graphene Paint Offers Rust-Free Future

Graphene Paint Offers Rust-Free Future

Reuters - Innovations Video Online (Oct. 21, 2014) British scientists have developed a prototype graphene paint that can make coatings which are resistant to liquids, gases, and chemicals. The team says the paint could have a variety of uses, from stopping ships rusting to keeping food fresher for longer. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins