BLACK ROCK — The Arkansas Highway and Transportation Department will hold a public meeting Tuesday to discuss plans to replace a U.S. 63 bridge that was posted with lower weight limits earlier this year.
The meeting will be held from 4 to 7 p.m. at Black Rock City Hall, 491 Elm St.
Plans call for replacing the two-lane bridge over the Black River in Lawrence County.
The new four-lane bridge will be built adjacent to the current bridge.
Replacement of the 2,608-foot-long bridge, which carries 10,000 vehicles a day, is scheduled to begin in 2013.
The public is invited to visit any time during the scheduled hours to view displays, ask questions and offer comments.
More information is available by contacting the department’s environmental division at (501) 569-2281.
In February, the weight limit on the bridge was posted at 33 tons for five-axle trucks. The weight limit on unposted bridges is 40 tons, but an evaluation team from the department recommended the new posted limit based on an engineering analysis of the structure and an on-site investigation.
The U.S. 63 bridge is one of five bridges in the state that is a deck-truss design, which is a structure supported by steel beams in the shape of an arch below the driving surface.
In 2007, an eight-lane bridge of similar design that carried Interstate 35W across the Mississippi River in Minneapolis collapsed suddenly during the afternoon rush hour, killing 13 people and injuring another 145.
A 2008 report from the National Transportation Safety Board said weight on the bridge was a major factor in its collapse. Construction was ongoing at the time of the accident. Investigators also found that 24 “underdesigned” gusset plates went undiscovered in reviews during the bridge’s design and construction. Gussets are used to tie steel beams together and are attached using rivets or bolts.
Significant increases in the bridge’s weight because of improvements through the years, along with increased weight on the bridge due to construction equipment and rush-hour traffic the day of the collapse, likely contributed to the failure of the faulty plates, according to the report.
Arkansas, Pages 12 on 10/31/2011