Originally opened in 1975, Jack Trice Stadium at Iowa State University (ISU) has hosted football games for the Cyclones for a half-century. Now, the new East Gateway Pedestrian Bridge offers a safe, reliable means for fans to access the stadium over University Boulevard, a four-lane street that experiences heavy traffic on game days. With a need to blend creativity and practicality, Raker Rhodes Engineering partnered with Wells to design the pedestrian bridge, leveraging precast concrete beams, columns, double tees, slabs, and architectural walls in the design.
A Championship-Caliber Solution
Stretching a quarter mile in length, the East Gateway Pedestrian Bridge connects the stadium with parking areas to the east. The bridge, which complies with Americans with Disability Act (ADA) requirements, has two stair towers featuring architectural precast concrete panels embellished with ISU-themed lighting, which improves visibility for the bridge’s users while also inspiring fans on gamedays. The structure of the bridge is anchored by 77-ft-long spans composed of 42-in.-deep double tees. Given the size of the bridge, a steel design would have been prohibitively expensive. Therefore, the project team chose precast concrete products for most of the structure, including the walkway’s slab sections. The result is a bridge that is both cost effective and durable.
Important considerations during the design process were the live loads and vibration limits for the structure during periods of peak pedestrian traffic. Instead of static loading, the engineers used dynamic load design to account for movement and vibrations caused by people walking across the bridge. Ensuring that the East Gateway Pedestrian Bridge could support the live loading of users while still maintaining its dynamic load capabilities was critical. As a result, extensive residency calculations were performed to guarantee that the bridge would not bounce excessively under pedestrian traffic.
The project’s original schedule was established prior to the start of the COVID-19 pandemic. and had experienced several delays. As such, work had to be completed under a tight timeline so that the bridge could be finished in time for ISU’s next football season. By going with what was essentially an all-precast concrete design, the project benefited from the material’s many advantages, including the efficiency of off-site fabrication and expedited on-site erection.
With aesthetic appeal and long-term durability, the East Gateway Pedestrian Bridge is a championship-quality solution that fosters a sense of community and inspires school pride among those who support the ISU Cyclones.
Mason Nichols is a Grand Rapids, Mich.-based writer and editor who has covered the precast concrete industry since 2013. |