Golden Gate Bridge to a site near the bridge. In May 1987, as part of the 50th anniversary celebration, the Golden Gate Bridge district again closed the bridge to automobile traffic and allowed pedestrians to cross the bridge. However, this celebration attracted 750,000 to 1,000,000 people, and ineffective crowd control meant the bridge became congested with roughly 300,000 people, causing the center span of the bridge to flatten out under the weight. Although the bridge is designed to flex in that way under heavy loads, and was estimated not to have exceeded 40% of the yielding stress of the suspension cables, bridge officials
Golden Gate Bridge million. Since its completion, the Golden Gate Bridge has been closed because of weather conditions only three times: on December 1, 1951, because of gusts of ; on December 23, 1982, because of winds of ; and on December 3, 1983, because of wind gusts of . An anemometer, placed midway between the two towers on the west side of the bridge, has been used to measure wind speeds. Another anemometer was placed on one of the towers. Modern knowledge of the effect of earthquakes on structures led to a program to retrofit the Golden Gate to better resist seismic