The Birmingham Bridge on South Side reopened at 10 a.m. on Monday, Sept. 8.
Repairs to replace the rocker bearing system under the northbound side of the bridge with a new neoprene pad system have been completed. Work is now set to begin to replace the pier on the southbound side of the Birmingham Bridge that shifted on February 8. However, this will not require the southbound lanes to be closed as PennDOT originally anticipated. This will allow traffic to return to normal patterns on the Birmingham Bridge for the first time since the incident occurred.
It should be noted the southbound side of the Birmingham Bridge will be opened for cars and buses only; trucks will still need to use the posted truck detour. Traffic on the northbound side of the bridge will be unrestricted after the bridge fully reopens.
When the repair plans for the Birmingham Bridge were being developed early this year, the schedule called for a portion of the southbound bridge deck above the shifted pier to be removed. After further review, the pier can now be removed and replaced without removing the deck or disrupting traffic on the southbound bridge. Demolition of the southbound pier will begin on Monday.
The southbound pier that will be replaced is 60 feet high, 72 feet wide and weighs 1,050 tons. Once the pier is removed, the foundation will be strengthened and a new pier constructed. A new neoprene bearing system will also be installed. Work on the southbound pier and bridge spans is expected to be completed in January 2009.
The estimated overall cost of the incident including the replacement of the southbound bridge pier is approximately $7.5 million (estimated cost to remove and replace southbound pier is approximately $4 million).
The Birmingham Bridge was closed to traffic Friday morning, Feb. 8, after the superstructure on the southbound lanes shifted downward as a result of rotation of the rocker bearings. After further inspection that morning, it was determined the bridge pier had moved as well. PennDOT reopened the southbound side of bridge to traffic in early March after steps were taken to secure the bridge in its original location using temporary steel shoring towers.
A forensic inspection determined a tilting of the rocker bearing system over time caused by corrosion and debris from leaking expansion dams caused the incident. Crews have been working over the summer to replace the rocker bearing system on the closed northbound side of the bridge.
The Birmingham Bridge was opened to traffic in 1976 and carries nearly 23,000 vehicles per day. The bridge is 2,747 feet long consisting of 19 spans. The design of the main span over the Monongahela River is a steel-tied arch and the approach spans are steel, multi-girder structures.
Following the February incident on the Birmingham Bridge, PennDOT District 11 began to reassess rocker bearings on the 1,741 state-owned bridges in Allegheny, Beaver and Lawrence counties. Of those bridges, 241 have similar rocker bearing systems. PennDOT has completed assessments on all of these structures and taken any immediate corrective actions that were needed.