Puente Milenium vibracion lateral sincronizada 1
The Unexpected Movement of a Bridge
Initial Opening and Public Reaction
- The bridge was completed with an investment of around 20 million euros and opened to the public on June 10, 2000. On its opening day, approximately 100,000 people crossed it, leading to unexpected oscillations.
- The speaker expressed disappointment upon witnessing the bridge's movement, as it posed a significant safety issue for pedestrians who could potentially fall or get injured.
Understanding the Problem
- The company Haru was tasked with investigating the cause of the noticeable lateral vibrations that occurred when many pedestrians crossed simultaneously.
- It was noted that while walking on a moving surface (like a ferry), individuals anticipate movements to maintain balance; however, this collective behavior among pedestrians created excessive lateral forces on the bridge.
Discovering Key Insights
- Haru conducted tests revealing a clear relationship between lateral forces exerted by pedestrians and their impact on the bridge's stability.
- A breakthrough moment occurred when they developed a new formula to calculate "lateral synchronized excitation," which describes how pedestrian movements contribute to overall vibrations.
Solutions Implemented
- Two options were considered: strengthening the structure or implementing damping methods. Strengthening would compromise aesthetics and require significant structural changes.
- Ultimately, dampers were installed along the bridge’s underside to absorb energy from pedestrian movements. This solution aimed to preserve the original design while effectively managing vibrations.
Testing Effectiveness
- After installing dampers at various points along the bridge, extensive testing involved crowds crossing repeatedly.