The replacement of the Commercial Street Bridge on the Parkway East is going to bring short-term pain to avoid more than four years of lane closures.The bridge replacement will require the entire parkway to be closed for at least a month in 2026 while the current structure is demolished and the new bridge is slid into place.“This is one of the most complex and important project investments in the Western Pennsylvania area,” Jason Zang, the district executive for PennDOT’s Pittsburgh-region engineering district, said during an online meeting with neighbors in August.Zang added that the construction team has been hired and designs have been completed for the new bridge that will replace the 73-year-old structure that carries 100,000 vehicles a day despite a weight limit.“Due to its age, deterioration is accelerating, and recurring maintenance costs are getting prohibitive,” said Nick Burdette, the senior bridge engineer.The existing bridge, built in 1951, was determined to be a historic structure eligible for the National Register of Historic Places, though it was not listed. The 863-foot-long concrete bridge is made of three spans each held up with a concrete arch.Because of the history of having arches span the valley over Commercial Street and based on responses from residents, the Pennsylvania Department of Transportation chose a steel bridge with a Delta design, which is a large open arch with half arches on either side.The structural steel will be painted green.The Commercial Street Bridge on the Parkway East will be replaced in 2026, requiring the entire parkway to be closed for at least a month. Photo by Ann Belser.Burdette said the engineers and PennDOT had considered a bridge reconstruction method that would involve closing parts of the bridge, demolishing them, rebuilding and moving on, but that would have involved four years of lane closures. Instead, they will build a bridge next to the bridge, demolish the old bridge then slide the new bridge into place.“This is a very ambitious and complex endeavor, and we are excited to construct it this way,” Zang said.During the three-week closure, planned for July 2026, traffic will be detoured off the parkway at the Wilkinsburg exit to Penn Avenue onto Fifth Avenue and then through Oakland before returning to the parkway at the Boulevard of the Allies entrance. Eastbound traffic will take a similar route.In September 2025, the parkway will close for nine nights when the structural steel will be trucked to the existing bridge and lowered into Frick Park, where the real action will take place on the bridge construction, said Michelle Olszewski, the project manager for Pittsburgh-based Fay, S&B USA Construction, which will build the bridge.Under the bridge, both Commercial Street and the Nine Mile Run Trail will be rerouted to accommodate the construction. A temporary bridge abutment will be built where Commercial Street is now, and part of the trail will have a temporary shelter to protect users.Similarly, Nine Mile Run will have a temporary cap over it both to protect the waterway from debris and allow for construction equipment to cross over the stream.After the bridge is in place and the parkway reopens, Commercial Street will remain closed while construction crews clean up the demolition debris and restore the roadway.The post Innovative bridge replacement to close Parkway East for a month appeared first on NEXTpittsburgh.