The Birmingham Bridge will be closed for approximately two weeks as Pennsylvania Department of Transportation crews try to determine the cause and severity of a shift in a bridge span and pier.

"We do have three crews out there, two PennDOT crews and a consultant inspection crew, and they're going as fast as they can, but that's a massive structure," said PennDOT spokesman James Struzzi. "They're going over it with a fine-toothed comb, so it's going to take some time."

The bridge -- which carries nearly 23,000 vehicles over the Parkway East, Second Avenue and Monongahela River each day -- was closed to traffic on the morning of Friday, Feb. 8 after the bridge deck on the southbound lanes shifted downward because of a rotation in the rocker bearings. An inspection determined the bridge pier had moved as well.

Trumbull Corp. of West Mifflin, PennDOT's contractor, is erecting shoring towers on both sides of the shifted pier. Once the towers are complete, they will support the weight of the bridge so the shifted span can be moved back into place. Temporary jacks are being installed on the northbound span as a precaution.

The cause of the shift has not yet been determined. In a Sunday news release, PennDOT said there was no reason to believe any structural problems existed with the bridge before the incident on Friday.

Kent Harries, an assistant professor of civil and environmental engineering at the University of Pittsburgh, said until crews determine the cause of the rocker bearing shift, it's hard to know if it's an isolated problem or a more serious issue that may include costly repairs and a more lengthy closure.

"It looks like an isolated event at this point," Harries said. If that is the case, the northbound lanes may be opened to traffic while the problem is repaired.

The Birmingham Bridge, which was opened to traffic in 1976, was last inspected in July 2006.

The bridge received a $3 million rehabilitation in 2007, which included expansion dam repairs and replacements, concrete deck repairs, structural steel repairs, spot painting, approach slab repairs, deck repairs and small repairs on columns and pier caps.

Source: Pittsburgh Business Times