PennDOT briefs public on Commercial Street Bridge replacement

The best aspect of the new Commercial Street Bridge along the Parkway East approaching the Squirrel Hill Tunnel may be that it won’t have to be replaced for 100 years.

The second best may be that the Pennsylvania Department of Transportation and designer HDR found a way to replace the bridge without creating an extended traffic nightmare for the 100,000 vehicles a day that use the highway to get into and out of Pittsburgh.

PennDOT, the design team and the contractor for the $95 million project held a virtual meeting Wednesday to explain the construction process to the public. The bridge will be replaced over the next three years, but most of the pain for motorists won’t be until July 2026.

PennDOT District Executive Jason Zang called the project “very ambitious and complex” because it will involve building the new bridge on temporary piers just south of the existing bridge over the next two years. Then, likely in July 2026, the highway will be closed for 25 days while crews demolish the old bridge, clear debris and slide the new bridge into place.

That will allow the busy highway to stay open most of the time, except for about 18 days when there will be short-term overnight lane restrictions for work on a retaining wall along the outbound lanes just past the Squirrel Hill Tunnel and the delivery of steel beams and other material that will be lowered from the highway to Frick Park below for construction.

Zang said the other possibility would have been staged construction, where traffic would be reduced to one lane in each direction for the first two stages and the highway completely closed for the third stage. That would have resulted in several years of traffic disruptions.

Nick Burdette, project manager for designer HDR, said sliding the bridge into place was the “overwhelming consensus” of the public, PennDOT and the design team.

Contractor Fay S&B USA expects to complete the first task in construction by the end of the week: lowering the inbound exit ramp at Wilkinsburg to provide more room under the highway. That will be the primary detour route when the highway is closed, and the extra room is needed to accommodate tall trucks.

In the next few weeks, crews will begin relocating Commercial Street and a trail in Frick Park under the bridge. That will create the pad where the new bridge will be constructed beginning next year.

They also will build a temporary causeway over Nine Mile Run for use during construction.

Work on the retaining wall should begin in the winter, followed by construction of the new bridge beginning next year.

The new bridge will have two support arches shaped like the letter V, which Burdette said will provide an “open, airy feel” in the bridge’s park setting. The railings on the sides of the bridge also will be open to provide a view of the park below.

John Myler, PennDOT’s senior assistant construction manager, said residents shouldn’t notice any more noise from the new bridge. It could be quieter because it will only have two expansion dams instead of three, and it will have a grooved surface instead of flat.

The demolition of the existing bridge will be a combination of traditional demolition and explosives, said Michelle Olszewski, project manager for Fay. The bridge will be wrapped with pads to make sure pieces from the explosion fall directly to the ground and cause minimal damage.

Myler quipped that residents should be assured the explosion will be tightly controlled because, “Our [new] bridge will be closer than anything else.”

After the new bridge is in place, Commercial Street is expected to remain closed for a few months for debris removal, park restoration and relocation to its original path.

In response to a question about Nine Mile Run, Myler said the department is working closely with the state Department of Environmental Protection to ensure it will be maintained properly. He said the stream will be “in better shape than it is today” when the project is finished.