Constructed between 1957 and 1977, I-579 runs through central Pittsburgh connecting Pennsylvania Route 885 to I-279. The section of the highway that runs below street level near the former site of the Civic Arena created a 300-foot-wide canyon between Pittsburgh’s historic Hill District and the city’s downtown and cultural center. Bridges on Centre Avenue and Bigelow Boulevard served as the primary connection points across this section of highway, but their deteriorated and substandard sidewalks limited options for pedestrians to safely cross into Downtown Pittsburgh or access public transit on the other side of the highway.

After the demolition of the Civic Arena in 2012, redevelopment efforts led by the City of Pittsburgh, the Urban Redevelopment Authority (URA), the Sports & Exhibition Authority of Pittsburgh and Allegheny County (SEA), and the Pittsburgh Penguins ice hockey team, among others, sought to use the 28-acre site for mixed-use and mixed-income developments that could reconnect the Hill District to Downtown Pittsburgh. Expanding safe multimodal options for crossing the sunken portion of I-579 was a central part of this vision.

SEA was selected as design lead for the project. They engaged Hill District community members to conceptualize a public park covering the 300 feet of highway between Bigelow Boulevard Bridge and Centre Avenue Bridge. The goals of the project were not only to provide a safe multimodal crossing and new public space for community members, but also to catalyze further investment in support of Lower Hill District redevelopment.

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In 2015, SEA partnered with the City of Pittsburgh to secure a $1 million planning grant from USDOT's Transportation Investment Generating Economic Recovery (TIGER) VII program for preliminary design and stakeholder engagement. With this initial funding, SEA and the City convened additional partners, including the Pennsylvania Department of Transportation (PennDOT), to achieve two important milestones toward construction funding eligibility. First, the Cap Project was approved as part of the Southwestern Pennsylvania Commission’s (SPC) Long-Range Plan. Second, with PennDOT’s support, the project received NEPA review through a categorical exclusion from the Federal Highway Administration (FHWA). In 2016, FHWA awarded SEA and the City of Pittsburgh a $19 million TIGER VIII grant for final design and construction of the I-579 Cap Project, helping secure an additional $13 million in funding matches from state, local, and private contributors.

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SEA led an extensive stakeholder engagement and design review process, beginning with the $1 million TIGER VII planning grant from USDOT and lasting until project construction in 2019. During this period, SEA and project partners held more than 50 stakeholder meetings to gain buy-in, gather feedback on project design and park features, present preliminary and final designs for community input, and engage local artists to design the park’s art installations. Community meetings were hosted at familiar locations in partnership with the Hill Community Development Corporation (CDC), Community Empowerment Association, and other local organizations to maximize participation.

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To design the cap, the team needed to develop project-specific standards and approaches to cover the unique space between the Centre Avenue and Bigelow Boulevard bridges, including a change in surface elevation between the two sides of the highway. One of the key challenges the team faced was creating new foundational structures capable of supporting the park’s load while preserving the highway’s retaining walls and minimizing impacts to existing foundations. To address this challenge, the design team chose an innovative foundation technique that involved drilling deep, narrow supports behind the existing walls. For the cap structure, the team chose conventional materials, including precast concrete beams set across four multicolumn piers installed in gore areas (the space between converging lanes) and medians. Lightweight foam blocks would be placed on top of the structure to accommodate the park’s topography while minimizing soil weight. The design team also included multiple layers of waterproofing between the park and cap structure to minimize future maintenance and extend the life of the project.

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Construction of the I-579 Cap Project took place between June 2019 and November 2021. Throughout construction, the project team minimized disruptions to highway traffic, closing just one exit ramp and working within small construction areas between lanes to drill the multicolumn piers. Limited nighttime closures were allowed while the construction team lifted in 126 concrete beams to close off the roof of the cap—a process that took just 38 days. After completing the structural cap, engineered foam blocks and soil were laid on top of the beams, followed by final landscaping and park construction to make Frankie Pace Park a reality.

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Today, the I-579 Cap Project provides Hill District residents safe routes to Downtown Pittsburgh, public transit from the nearby Steel Plaza subway station, and improved access to an estimated 78,000 jobs. Frankie Pace Park, which continues to be operated and maintained by the City of Pittsburgh, gives Hill District residents access to three acres of outdoor recreation, event, and community space. The project will continue to support ongoing development and reinvestment in the Lower Hill District as part of the Lower Hill Redevelopment Plan. The project has received numerous awards, including the 2022 national grand prize in the America's Transportation Awards Competition.

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