The placement of the fifth self-anchored suspension span tower will bring the tower lift up to 495 feet. Currently, the tower stands 480 feet high.
The last tower section is scheduled to be installed later this year, boosting the structure to a final height of 525 feet.
Construction of the first tower section began last July, with the second following in October, the third in December and the fourth just last month.
Caltrans officials say the $6.3 billion project to build the new eastern span and make the entire Bay Bridge more seismically safe is still on time and is slated to be finished in 2013.