Michigan Department of Transportation

I-94 Gateway Arch Bridge

Detroit, MI

Constructed as part of a larger I-94 reconstruction project in anticipation of Super Bowl XL, the Gateway Arch Bridge is a signature modified tied arch structure carrying six lanes of traffic just outside of Detroit.

The bridge’s design is an innovative blend of form and function—from the roadway, the structure maintains the sleek appearance of a true arch bridge, further enhanced by pressurized arch ribs resembling footballs. Below ground, the structure’s longitudinal ties compensate for unstable soils which would have rendered a true arch design impossible.

Safety and ease of maintenance were also key to the design; the bridge’s arch ribs are sealed and pressurized to maintain constant deflection and allow for easy inspection access with minimal traffic disruption. The air sealed within the ribs is dry, which helps to prevent moisture that could lead to corrosion.

Hailed as one of the world’s most innovative structures when it was constructed, the I-94 Gateway Arch Bridge received several national awards acknowledging its innovative approach to solving redundancy issues that are common with tied arches and the soil requirements of a true arch. Described by the Detroit Free Press as melding the city’s passion for football with a love for autos, it was added that “only time will tell what place [the Gateway Arch] will take in metro Detroit’s Gallery of Public Art.”

Project highlights

  • First-ever modified tied arch structure with longitudinal ties buried below ground
  • Independent foundation system accommodates unstable soils
  • Easy future maintenance and inspection
  • Striking design featuring football-shaped arch ribs