Proj Overview


When the Fern Follow Bridge in Pittsburgh’s Frick Park collapsed on January 28, 2022, four people sustained non-life-threatening injuries. Had the bridge collapsed an hour later, during peak commuter time, it could have been a different story.

Following the collapse, an emergency project team was assembled and given the green light to start working on the rebuild immediately. With conventional methods, replacing a bridge this size typically would have taken three to four years, plus the time required to redesign the bridge, plan the bridge construction, obtain approvals, prepare the site, and install substructure elements. Using prestressed concrete beams for the bridge superstructure assisted the Fern Hollow Bridge completion in less than a year.


One obstacle was related to the design process. “The primary challenge in the design phase was the accelerated time factor,” says Greg Gorman, president and COO of PennStress. “The team performed the incredible feat of redesigning the original 450 ft span steel K-frame structure to a three-span prestressed concrete beam structure in a few months. Highly expedited shop drawing preparation by PennStress and subsequent review and approval by the project team were a success as well.” Production, which was also critical, did not pose significant difficulties. “We had no out-of-the ordinary challenges in the production activity for these twenty-one large, prestressed beams since we are accustomed to producing beams of this size,” notes Gorman.

Delivery turned out to be the greatest hurdle for PennStress in the process of this bridge replacement. “We worked with the project team immediately after our award to determine the safest feasible delivery routes for the beams through the city to the jobsite,” he says. “When it came time to deliver the super-load beams, the city of Pittsburgh operational managers, the police, and the motorcycle police did an excellent job of guiding us safely through the city to the site.”


The project team took a big step in rebuilding the bridge, opting to replace the old steel bridge with prestressed concrete beams from PennStress. This decision was made because of precast concrete’s exceptional strength and flexibility, which fueled the project’s extraordinary construction rate. Using precast concrete helped the project team meet critical high-performance measures while reducing the need for other materials and human resources. Because precast concrete is fabricated off-site in a factory-controlled environment, PennStress was able to guarantee consistent, accurate pours every time and deliver structural components to the jobsite on a just-in-time basis.

Read the full Project Spotlight in the 2023 May-June, Bridges issue of the PCI Journal


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Project Team




Swank Construction Company


Pennsylvania Department of Transportation, City Of Pittsburgh

PCI Certified Precast Producer


Key Project Attributes

The use of prestressed concrete for the Fern Hollow Bridge replacement delivered the following benefits:

  • Accelerated construction speed with off-site fabrication, minimal disruption to the surrounding environment during construction.
  • A high-quality, resilient, and low maintenance three-span bridge for a 100-year service life.
  • The bridge can withstand inclement weather, a harsh environment, hurricane-level winds, and occupational impacts from vehicles.
  • Time and money savings while achieving the desired look and bridge features.

Project/Precast Scope

  • The replacement structure is a three-span bridge, almost 100 ft (30 m) above Frick Park.
  • There are 21 prestressed concrete bulb-tee beams.
  • The beams are 155 ft (47 m) long, each weigh more than 100 tons (90 tonnes), and feature 10 ksi (68 MPa) concrete strength.