Here's a breakdown:
* The Bridge's Design: The bridge's design, with its relatively narrow deck and flexible suspension cables, made it susceptible to wind forces.
* Wind Conditions: On the day of the collapse, winds were strong and had a specific frequency that resonated with the natural frequency of the bridge's deck. This caused the bridge to oscillate vertically, like a giant flag waving in the wind.
* Aerodynamic Instability: As the oscillations increased in amplitude, the wind's interaction with the bridge's deck became increasingly unstable. This created a feedback loop where the wind further amplified the bridge's oscillations.
* Resonance: The wind's frequency matched the bridge's natural frequency, leading to a phenomenon called resonance. This amplified the bridge's oscillations until the structure could no longer withstand the forces and collapsed.
In simpler terms: The wind acted like a giant invisible hand pushing and pulling the bridge, causing it to sway and eventually break apart.
This event is a classic example of how understanding the interaction between structures and wind is crucial for designing safe and reliable bridges. The collapse of the Tacoma Narrows Bridge led to significant advancements in bridge design and wind engineering.