Port Authority of Allegheny closes bridge that had shifted

Feb. 7, 2022
Engineers found a portion of the Saw Mill Run Boulevard Bridge used by buses and light-rail trains shifted; it is stable, but will remain closed until repairs are made.

The Port Authority of Allegheny County (Port Authority) halted transit traffic along a portion of its South Busway after engineers discovered a portion of the Saw Mill Run Boulevard Bridge, also referred to as the Palm Garden Bridge, had shifted. The discovery was made on Feb. 4 and the Port Authority says the bridge is stable, but will remain closed until repairs can be made.

 The Port Authority is working with third-party contractors to develop a timetable for the repairs on the 1,052-foot span and no cause for the shift has been determined.

The Port Authority said an employee noticed the morning of Feb. 4 that a joint on the deck of the bridge appeared to have expanded. Only buses and light-rail trains operate on the bridge and once transit traffic was suspended, engineers and a bridge consultant examined and surveyed the joint for signs of distress and movement. The bridge was last inspected in October 2020 and assigned a rating of “Satisfactory (6).”

Unfortunately, the condition of Pittsburgh area bridges has been an area of focus with the Fern Hollow Bridge collapse that injured 10 people occurring seven days before the shift in the portion of the Saw Mill Run Boulevard Bridge was discovered. Both the Saw Mill Run Boulevard Bridge and Fern Hollow Bridge were built in the 1970s with the Fern Hollow Bridge opening in 1973 and the Saw Mill Run Boulevard Bridge in 1977. While the Fern Hollow Bridge is maintained by the city, the Saw Mill Run Boulevard Bridge is owned and maintained by the Port Authority.

The Port Authority said contractors will begin to mobilize on the repairs soon and work will require the removal of the overhead power lines. The work will consist of removing a portion of the concrete bridge deck to access the bridge's superstructure; removing the existing anchor bolts and resetting the position of the bridge; repairing and/or replacing the rail joint; and replacing the portion of the concrete deck that they remove. Once repairs are complete, the overhead power lines will be replaced and the bridge reopened.

Red Line rail cars will detour via the Blue/Silver Line from Overbrook Junction to Downtown. A rail shuttle will operate between Overbrook Junction to Potomac Station. Bus shuttles will operate between Potomac Station and Station Square. Bus routes impacted include the 39, 41, Y1, Y45, Y46, Y47 and Y49. 

About the Author

Mischa Wanek-Libman | Group Editorial Director

Mischa Wanek-Libman serves as editor in chief of Mass Transit magazine and group editorial director of the Infrastructure and Aviation Group at Endeavor Business Media. She is responsible for developing and maintaining the editorial direction of the group and is based in the western suburbs of Chicago.

Wanek-Libman has spent more than 20 years covering transportation issues including construction projects and engineering challenges for various commuter railroads and transit agencies. She has been recognized for editorial excellence through her individual work, as well as for collaborative content. 

She is an active member of the American Public Transportation Association's Marketing and Communications Committee and serves as a Board Observer on the National Railroad Construction and Maintenance Association (NRC) Board of Directors.  

She is a graduate of Drake University, where she earned a Bachelor of Arts degree in Journalism and Mass Communication with a major in magazine journalism and a minor in business management.