You won’t believe but a Crowd of people almost destroyed the Golden Gate Bridge on It’s 50th Anniversary. The 50th-anniversary celebrations of the amazing feat of engineering were held on 24th May, 1987. A crowd gathered on the bridge and weighed 50% more than the original design load of the bridge.
The bridge was closed to traffic in the morning and was open only to pedestrians. Surprisingly the crowd that showed up was much more than the anticipated audience. The bridge featured a conventional arch that sported a peak in the center. However, on that day, the peak flattened out and the center dropped 7ft because of the weight. The cables stretched and subsequently, the towers were pulled inward. As it turns out, bumper-to-bumper cars don’t weigh as much as shoulder-to-shoulder crowd.
The seemingly scary story wasn’t that grim actually. In fact, according to most engineers, the actual danger of a collapse taking place was quite small. Why? Because in the preceding year, substantial dead weight had been removed from the span, and as a result, the actual weight of the crowd was not 50% above the design load, but 14% below. Bridges even incorporate a safety factor with the design load in order to prevent collapse due to a gust of wind at the design loading.
The actual danger in this scenario was of a panic. Such big crowds with narrow escape routes is a potential catastrophe waiting to happen. Thankfully the crowd didn’t notice the flattening of the bridge and only a very limited number of people in the crowd actually noticed the effect.
Another amazing fact that you all probably don’t know about the Golden Gate Bridge is that one of the engineers was tasked with solving 33 algebraic equations that involved 6-36 variables each for ensuring that the bridge can withstand any storm that might hit the Pacific. For those of you, who don’t get the picture, solving for this many variables means that you’ll have to solve the equation in over 5,000 ways.
A pretty amazing feat of engineering, isn’t it?