Question
Was resonance instrumental in the collapse of the Tacoma Narrows bridge?
Answer
The collapse of the Tacoma Narrows Bridge in 1940 is often attributed to resonance, but the actual cause was more complex. While some studies suggest that resonance played a role, others highlight different mechanisms.
Key Factors in the Collapse
Resonance and Oscillations: Some research indicates that the collapse was due to a sudden transition from longitudinal to torsional oscillations caused by resonance phenomena (Hajjej, Al‐Gharabli and Messaoudi, 2021; Al‐Mahdi, Al‐Gharabli and Zahri, 2023). This transition led to strong vibrations that the bridge could not withstand.
Aeroelastic Flutter: The bridge experienced vertical and torsional vibrations due to aeroelastic flutter, a phenomenon where wind-induced forces cause oscillations that grow in amplitude (Song et al., 2022). This flutter was a critical factor in the bridge’s failure.
Positive Feedback Mechanism: Contrary to the resonance theory, another explanation involves a positive feedback mechanism between the bridge and the wind, similar to the behaviour of wind instruments. This mechanism, rather than resonance, was identified as a key factor in the collapse (Unruh, 2024).
Parametric Resonances: A detailed explanation suggests that parametric resonances, involving complex interactions between structural dynamics and wind forces, contributed to the collapse. This explanation aligns well with observed data from the incident (Gazzola, Jleli and Samet, 2022).
While resonance is often cited as a cause of the Tacoma Narrows Bridge collapse, the actual failure involved a combination of factors, including aeroelastic flutter and complex feedback mechanisms. These insights highlight the importance of considering multiple dynamic interactions in bridge design to prevent similar failures.
References
Unruh, W., 2024. The collapse of the Tacoma Narrows bridge– Why?. The Journal of the Acoustical Society of America. https://doi.org/10.1121/10.0026856
Hajjej, Z., Al‐Gharabli, M., & Messaoudi, S., 2021. Stability of a suspension bridge with a localized structural damping. Discrete & Continuous Dynamical Systems – S. https://doi.org/10.3934/dcdss.2021089
Al‐Mahdi, A., Al‐Gharabli, M., & Zahri, M., 2023. Theoretical and numerical decay results of a viscoelastic suspension bridge with variable exponents nonlinearity. Mathematische Nachrichten, 296, pp. 5426 – 5453. https://doi.org/10.1002/mana.202200338
Gazzola, F., Jleli, M., & Samet, B., 2022. A new detailed explanation of the Tacoma collapse and some optimization problems to improve the stability of suspension bridges. Mathematics in Engineering. https://doi.org/10.3934/mine.2023045
Song, D., Kim, W., Kwon, O., & Choi, H., 2022. Vertical and torsional vibrations before the collapse of the Tacoma Narrows Bridge in 1940. Journal of Fluid Mechanics, 949. https://doi.org/10.1017/jfm.2022.748
