Golden Gate Bridge Will Be Under Construction For The Next Decade To Prepare For The 'Big One': Report

SAN FRANCISCO, CA — While the Golden Gate Bridge is unlikely to collapse during the next major earthquake or even the Big One, officials are preparing now to retrofit the bridge in an effort to prevent that from ever happening, the San Francisco Chronicle reported.

While the bridge is designed to sway, the concrete roadway that spans the bridge and the pylons that reach to the ground at both ends are less flexible. That mismatch could be devastating.

They won’t be moving in sync, and they’ll be banging into each other,” John Eberle, an engineer for the Golden Gate Bridge, Highway and Transportation District, told the newspaper.

The bridge is about six miles east of the San Andreas Fault. It could also be shaken by a major temblor along the Hayward Fault, which is in the East Bay. According to the U.S. Geological Survey, there is a 72 percent chance of a 6.7-magnitude earthquake striking the Bay over the next 30 years. What's more, there's a 20 percent chance of a 7.5 quake hitting the region in that timeframe, the San Francisco Chronicle reported.

The San Francisco Chronicle reported that planned upgrades to reduce ground shaking include 40-foot-tall steel plates to reinforce the base of both towers, 38 massive shock absorbers — some weighing more than 26,000 pounds — and a strengthened steel lattice system to support the suspension span.

“The Golden Gate Bridge is a lifeline structure, and we are committed to opening up the bridge after a large-scale event,” Eberle said at a meeting earlier this year. “That’s why the extent of the retrofit is what it is.”

The intensive seismic retrofit, set to begin in January, would allow the iconic span to reopen to emergency vehicles within 24 hours and to the public within 72 hours of a major earthquake, John Eberle said. The bridge district aims to award a contract by December for the first of two project phases, which together are expected to cost nearly $1.8 billion and take approximately a decade to complete, according to the newspaper.

Read more from the San Francisco Chronicle: The Golden Gate Bridge is about to see 10 years of intensive construction