Tacoma Narrows Bridge

Evaluating parallel bridges through wind tunnel studies and analysis 

Shortly after opening in 1940, the original Tacoma Narrows Bridge, which crosses a narrow section of Washington’s Puget Sound, sustained high winds leading to collapse. Lessons learned from the 1940 disaster were incorporated into a new suspension bridge at the same site in 1950. By the 1990s, increased traffic created a need for a new adjacent, parallel bridge allowing each bridge to carry traffic in a single direction. RWDI investigated the aeroelastic stability of the proposed parallel bridge, its potential aerodynamic effects on the 1950 bridge, and the effects of modifications planned for the 1950 bridge. The new bridge opened in 2007 and today both bridges continue to serve the area’s transportation needs well.