70 Years: Spanning The Golden Gate

The Golden Gate Bridge of the future will look just like the bridge of the past -- except inside the skeleton of the structure, where it will all be different.

In five years, in time for its 75th birthday on May 27, 2012, the bridge will be stronger, safer and more resistant to earthquakes. But it will be hard to tell the difference.

The bridge district is spending $455 million -- much of it federal money -- on a project to allow the bridge to survive the earthquake everyone knows is coming.

Some of the work has been completed and in the years ahead, the main span -- with a breathtaking 4,200-foot space between the towers -- will be fitted with dampers that work like shock absorbers to keep the bridge standing in a quake.

The dampers allow the bridge to move, so the forces are dissipated. "We want it to be flexible so that it can roll with the punch,'' said Denis Mulligan, the bridge district's chief engineer

Some of the lateral bracing on the trusses under the roadway will be replaced. The rivets driven when the bridge was built in the 1930s will be replaced by newer, stronger bolts, twice as strong as the old rivets.