Construction is underway to replace Commercial Street Bridge, an 861-ft-long open spandrel concrete arch structure that rises up to 85 ft above Nine Mile Run and Frick Park in Pittsburgh, Pa. Built in 1951, the four-lane bridge is an integral part of the I-376/Parkway East, one of the most heavily traveled highways in western Pennsylvania with nearly 100,000 daily vehicles.

With the aging bridge already load-restricted due to structural deterioration, the Pennsylvania Dept. of Transportation and designer HDR evaluated a variety of methods for the design-bid-build replacement. An accelerated bridge construction slide-in technique was deemed the best option to accommodate alignment and topographic constraints.

Joseph B. Fay Co., Pittsburgh, will build the 825-ft-long, 80-ft-wide arched delta frame structure on temporary foundations. During a planned 25-day highway shutdown in summer 2026, Fay will remove the old bridge using conventional and explosive demolition techniques, then slide the 19-milion-lb replacement into place.

The $95-million project, scheduled for completion the following year, will include lowering a nearby interchange off-ramp to increase vertical clearance under the highway, sanitary sewer line relocation, guiderail upgrades and installation of traffic management technology.

The construction team will also restore disturbed areas of Frick Park, which is spanned approximately one mile to the north by the Fern Hollow Bridge. That structure dramatically collapsed in January 2022 and was reopened in less than one year following an accelerated reconstruction effort.