MDOT: Bridge-barge accident tests SHM technology
by For the MBJ
Published: April 25,2011
VICKSBURG — A recent barge crash into the I-20 Mississippi River Bridge in Vicksburg gave structural health monitoring (SHM) technology a chance to keep motorists safe and get the bridge quickly reopened by providing real-time information to bridge engineers in the wake of the incident. The structure, which had been hit by a grain-filled barge, was closed for hours as transportation officials scrambled to quickly assess the damage.
“The I-20 Mississippi River bridge was selected as one of the two SHM sites because it’s a critical crossing of the Mississippi, with the closest bridge about 50 miles away. It is also part of the Defense Strategic Highway Network and close to ERDC-Vicksburg,” said Steve Sweeney, structural engineer and SHM project engineer. “The system installed in November 2010 along with subcontractor support was called upon by the Louisiana Department of Transportation and Development, following the barge impact, to check for any indication of structural problems.”
The SHM system was conceived and Developed by the U.S. Army Engineer Research and Development Center and a team of contractors as part of the Office of the Secretary of Defense’s (OSD) Army Corrosion, Prevention and Control program, the SHM technology monitors in real-time the long-term degradation of steel bridges and determines the effect on the structure when conditions change such as corrosion, fatigue, or other forms of deterioration. The system on the I-20 Bridge is monitored by the U.S. Army Corps. of Engineers in conjunction with the Louisiana Department of Transportation and Development, who maintains the bridge.
The technology continuously monitors structures on which it is installed and can provide real-time information on sudden changes, making it a perfect fit for post-crash needs.
Immediately after the barge collision, “bridge engineers were en route, but were still a distance away when we received the call for help,” said Sweeney. “We checked for structural problems in the strain, displacement and tilt data. In addition, the system includes three cameras and we were able to look for visible problems.”
In the aftermath of the recent crash, the ability to see the bridge at a close range proved particularly useful. After a 30-barge tow vessel struck the old U.S. 80 bridge in the river’s annually flooded waters, the barge floated down stream and didn’t simply strike one of the I-20 structure’s piers – it also lodged against it. The barge eventually sank but remained lodged against that pier, leading to a multiple-week effort to remove the wreckage.
The I-20 Bridge is crossed by nearly 23,000 vehicles per day.
Source: Mississippi Department of Transportation
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