The Birmingham Bridge is back -- all lanes of it, after being restricted since Feb. 8 following the collapse of a southbound span onto a pier.

The Pennsylvania Department of Transportation announced yesterday afternoon that the huge arch structure over the Monongahela River would be fully reopened to regular traffic as of 10 a.m. Monday and to large trucks by the end of the day.

Originally, PennDOT planned to shift traffic from the southbound side to the northbound side after deteriorated rocker bearings were replaced, a task recently completed, in order to continue repair work.

Instead, engineers have devised a scheme whereby they'll be able to keep the southbound side open while pier No. 10, off of Second Avenue, is removed and replaced at a cost of about $4 million.

Demolition of the 60-foot-tall pier, which shifted in the incident, will begin Monday. Meanwhile, a lattice of temporary scaffolding will be used to support the southbound span that dropped about 8 inches and has since been lifted back into place.

The Birmingham Bridge, opened to traffic in 1976, carries about 23,000 vehicles a day between East Carson Street on the South Side and Forbes and Fifth avenues in the Soho area, where it also provides access to and from Downtown and Oakland. Traffic has been maintained since the incident, but only one lane in each direction.

A forensic engineering investigation determined that corrosion and debris from leaking bridge expansion dams caused the rocker bearings to "freeze" and tilt where two southbound approach spans join, also causing Pier 10 to shift slightly.

The incident triggered a special statewide inspection of hundreds of other bridges with the same or similar types of rocker bearing systems. While PennDOT discovered "issues" with some, only eight others in Allegheny County have required corrective action, including a Parkway West Bridge near Carnegie, the Highland Park Bridge and an I-579 bridge over Seventh Avenue in Pittsburgh.

In addition, the incident has prompted PennDOT to put more emphasis on preventive maintenance and to change bridge inspection and monitoring procedures.

The southbound land pier that's to be replaced is 60 feet high, 72 feet wide and weights 1,050 tons.

Once the pier is removed, the foundation will be strengthened and a new pier will be built.

Also, the contractor will install the same type of neoprene bearing system on the southbound approach spans as those that have since been installed on the northbound exit spans.

PennDOT has estimated the overall bridge failure, repairs, traffic mitigation and related activities have cost $7.5 million.