Moving 1,200 tons takes time. It took three hours beginning at dawn to lift the tower piece into a vertical position, then the rest of the day to lift and lower it into the foundation.
This is only the first section of one leg of the tower. There will be four legs made up of five pieces each.
The finished tower will hold a single cable that connects into the roadbed, circles the bridge and re-connects into the tower.
"As beautiful as this remarkable tower will be, and it indeed will be beautiful, the critical factor of this seismic retrofit is our emergency preparedness, Oakland Mayor Ron Dellums said.
Gray strips on the tower leg mark where shear link beams will connect a key seismic safety feature.
"In a massive earthquake, these tower legs can move independent of each other and those beams will bend and contort and break, we can simply unbolt them and rebolt new ones in after an earthquake and the bridge can remain open for emergency services," Caltrans spokesperson Bart Ney said.
At a ceremony marking the installation mayors from the cities linked by the bridge reflected on its history. Dellums was a child when it opened in 1937.
"When the Bay Bridge first opened up, they allowed people to walk on the bridge for a nickel or a dime and my folks told me they carried me as a tiny kid onto that bridge," Dellums said.
San Francisco Mayor Gavin Newsom says there was a time he thought a new bridge would never get built.
"The earthquake was 1989 and here we are 20 years later and we are a number of years away from this being completed; my long-winded point is not to rain on the party, but to acknowledge this," Newsom said.
Construction on the Bay Bridge is expected to be completed in 2013.