Actually, Bay Bridge's western span did get a lot done to its steelwork. It's just not that noticable because a lot of it was "under the hood", so to speak.
You can read more here:
http://baybridgeinfo.org/projects/west-span
Note the picture on top, which shows the black netting over parts of the towers.
Also take a look at the first picture in this thread, one of mine showing a close up of the tower. Look at the underside of the uppermost horizontal part at the top of the tower- note that it's latticed. Then look down at the underside of the x-brace immediately below it. That used to be a latticework of steel too, but they've either replaced or reinforced that old latticework with solid steel plate.
Also, have a look at the 4th picture down on the page I linked to- notice the steel beams that make up the bridge's stiffening truss. Those were once made of thousands of small steel pieces riveted together, and are now replaced by one-piece perforated steel crossbeams. That way they don't have thousands of rivets just waiting to fail in the event of an earthquake.
Bay Bridge ended up with something few women want- major weight gain. To the tune of 17 million pounds! Mind you, that 17 million pounds are all solid steel, making her much stronger than she previously was. I definately suggest reading the article linked to here, it should prove helpful.