1. IntroductionThis memo is a failure analysis report for the Tacoma Narrows Bridge. The bridge collapsed on November 7, 1940, just over four months after it opened to the public on July 1, 1940 (Green, 2006). The only casualties (good word??) of the bridge collapse were journalist Leonard Coatsworth's car and dog. Bridge design and failure will be discussed, as well as new methods of suspension bridge design.2. Description of Failure Other similarly constructed bridges, such as the Golden Gate Bridge in San Francisco, can have vertical oscillations with amplitudes of up to 2 feet and horizontal oscillations of up to 6 feet during strong windstorms (Levy, 1992). Due to oscillations visible in other similarly constructed bridges, oscillations in the Tacoma Narrows Bridge were expected. However, the magnitude of the oscillations experienced by the bridge and the time it took the bridge to dampen them were of concern to the engineers involved. The time it took for the Tacoma Narrows Bridge to dampen its oscillations was different from other suspension bridges of similar construction, namely the Golden Gate Bridge, whose oscillations were quickly damped due to its larger width-to-span ratio. (need a connecting phrase) Just before the bridge completely failed, the oscillations went from their standard vertical and horizontal to a violent twisting motion, this twisting motion, which reached nearly 45°, is what brought down the bridge. After a momentary lull in movement, the twisting resumed and the bridge began to break, starting with smaller suspension cables connecting the bridge deck and the 2 large main support cables. The breakage of the suspension cables meant that nothing was holding this part of the bridge deck together and it began...... middle of paper ...... stiffening trusses could have been used instead of beams stiffening solids to allow more airflow and reduced wind resistance (Levy, 1992). Additionally, the system should have been damped to ensure that its resonant frequency cannot be duplicated in nature and create a positive feedback loop and to ensure that any oscillations that occur are quickly slowed down. Works Cited Farquharson, F. B. (1940). Tacoma bridge collapse shrinks. The Scientific Monthly, 51(6), 574-578. Goller, R. R. (1965). The legacy of “Gertie at a Gallop”. Civil Engineering, 35(10), 50.Green, D. and Unruh, WG (2006). The Failure of the Tacoma Bridge: A Physical Model.74(8), retrieved February 23, 2010 from http://scitation.aip.org/journals/doc/AJPIAS-ft/vol_74/iss_8/706_1.html.Levy , M. (1992). Gertie galloping. WHY BUILDINGS ARE FALLING (p. 109). New York: W. W. Norton.