The original Tacoma Narrows Bridge was the first suspension bridge built across the Puget Sound in Washington. The bridge was strong but relatively light, narrow, and as it turns out—(too) flexible. On the morning of November 7, 1940, in a 42 mph (68 kph) wind, the 2,800-foot (853-m) main bridge span went into a series of torsional oscillations (side-to-side and up-and-down motion) in which the amplitude (size of the motion) steadily increased. This movement tore several suspension cables and broke the main span, causing the bridge to collapse. The failure of the bridge was a shock to the engineering community. How could a structure weighing more than tens of thousands of tons topple in moderate wind? What factor(s) did the engineers of the Bridge fail to include in their engineering analysis?
The original Tacoma Narrows Bridge was the first suspension bridge built across the Puget Sound in Washington. The bridge was strong but relatively light, narrow, and as it turns out—(too) flexible. On the morning of November 7, 1940, in a 42 mph (68 kph) wind, the 2,800-foot (853-m) main bridge span went into a series of torsional oscillations (side-to-side and up-and-down motion) in which the amplitude (size of the motion) steadily increased. This movement tore several suspension cables and broke the main span, causing the bridge to collapse. The failure of the bridge was a shock to the engineering community. How could a structure weighing more than tens of thousands of tons topple in moderate wind? What factor(s) did the engineers of the Bridge fail to include in their engineering analysis?
Step by step
Solved in 2 steps with 2 images
