See all those little dots on it that look like people? See how it's flattening out?
For the anniversary celebration, the bridge (road, not just sidewalks) was opened to pedestrians as it had been on its first day, but there are a lot more people in the bay area now. We showed up near the bridge at dawn, reached a nearby staging point by about 8 am, and had reached the first of the two concrete support sets by about 10 or 10:30, at which point we realized we'd be creeping across the bridge with tens of thousands of other people until dusk, so we turned around and crept back.
Eventually, the bridge authorities had to shut it down and turn everyone back. The bridge has always had a slight arch to it, but with all these people, the arch actually flattened out. No one expected the sheer numbers or weight.