Structural Design Expertise on Display on Pittsburgh’s Unique I-579 Cap

How do you design a park that will be built over an active interstate? That’s the challenge HDR’s team took on in Pittsburgh to deliver the I-579 Urban Open Space Cap. The cap covers about 300 feet of I-579 with a new 3-acre park and restores an important connection between the city’s historic Hill District and downtown.

Three of HDR’s engineering experts — Roger Eaton, Nick Burdette and Kyle Smith — wrote about the project for Aspire magazine. Eaton is a senior bridge engineer and led HDR’s work on the project. Burdette is a senior bridge engineer and Smith is a bridge engineer. The three explained the innovative solutions developed for the substructure and superstructure, including the use of micropiles in the foundation, redundant waterproofing and polystyrene blocks to reduce the dead load.

“The dense urban site and unique park loading for this new structure required an innovative design and construction expertise,” the authors wrote. “There are no design codes for bridges carrying a park, so project-specific criteria were developed to meet the demands that will be placed on the structure.”

Read the whole article, "Building a Park over an Interstate," in the Summer 2023 issue of Aspire, published by the Precast/Prestressed Concrete Institute.