The Tacoma Narrows Bridge was meant to look light. Its deck was slender and its lines were clean. It opened on 1 July 1940 as the third-longest suspension bridge in the world by main span, at 2,800 feet, and it began to move almost at once.
The Horror
Construction workers had already nicknamed it Galloping Gertie, because the deck rolled in the wind. On 7 November 1940 the wind was about 40 mph. Around a quarter to ten in the morning the bridge began to sway, and the motion turned into a twisting, one side of the deck rising as the other fell. Around eleven the main span fell into the Narrows.
Leonard Coatsworth, an editor at The News Tribune, left his car on the bridge and escaped on foot. The only death reported was Tubby, a three-legged cocker spaniel belonging to Coatsworth’s daughter, who was left in the car. Some people were hurt escaping or trying to rescue the dog. Coatsworth was later reimbursed for the car and its contents. No human deaths are recorded.
What the film does and does not show
The collapse was filmed by Barney Elliott and Harbine Monroe, who owned The Camera Shop in Tacoma, and their footage was sold to Paramount. It was added to the National Film Registry in 1998. Most copies play about 50% too fast because of a frame-rate mix-up, so the deck appears to move faster than it did.
The explanation taught for decades, that the wind shook the bridge at its natural frequency, is wrong. The failure was aeroelastic flutter in a twisting mode, in which the motion fed itself and grew without limit. Professor Frederick Burt Farquharson of the University of Washington had run wind-tunnel tests on the design, and the fixes he proposed were not carried out before the collapse.
The Modern Relic
The wreckage lies on the seabed about 180 feet down and now serves as an artificial reef. It is on the National Register of Historic Places. A replacement bridge opened on 14 October 1950, built on the original anchorages and tower pedestals.
The film remains the relic most people have seen. It is still used to teach how a structure can destroy itself in a steady wind.
