It took longer than expected, but Pittsburgh’s fire-damaged Liberty Bridge finally reopened last month. Traffic on the bridge, which handles 55,000 vehicles a day, was diverted for 24 days while general contractor Joseph B. Fay Co. and the Pennsylvania Dept. of Transportation worked nonstop to temporarily repair and realign a charred lower chord.
A Sept. 2 fire damaged 30 ft of chord truss subject to substantial loads. Jacking and localized heating straightened the chord and redistributed the load on the bridge. A temporary nine-ton weight limit was placed on the bridge, while crews added steel to strengthen the truss chord. That limit was removed on Sept. 29 as the bridge’s preclosure weight limit—30 tons—was restored.
A 40-ton weight limit is expected to be instituted when an $80-million rehabilitation project finishes in 2018.
Last year, Joseph B. Fay Co. began the full rehabilitation on the 2,663-ft-long bridge that has a 470-ft-long main span and a 60-ft-high water clearance. The project, which marks the bridge’s first rehabilitation since 1982, involves structural steel repairs. The project also includes bridge deck replacement, ramp reconstruction, painting, concrete repairs, signage improvements and a new alternating overhead lane-control system.
The fire started when a welder accidentally ignited tarps and plastic pipe. Joseph B. Fay Co. was charged $213,000 in “liquidated damages” for every weekday and $72,000 for every weekend the bridge was closed.
PennDOT originally said repairs would be completed by Sept. 19. However, because the team couldn’t find another case of a bridge damaged by fire in the same way, the process was slowed. Experts in bridge structural analysis and modeling, hydraulic jacking systems, application of heat to steel, materials science, and inspection and monitoring collaborated on the design for the repair. Ironworkers, supervisors and support labor played critical roles, as well.
Jim Wilkinson, executive vice president at Joseph B. Fay Co., said the firm is now committed to completing the ongoing rehabilitation project. “With the bridge reopened, this is our primary focus,” he said in a statement.