The first cost estimates, released in 1995, figured both east and west spans of the bridge could be upgraded for $250 million.
In September 2013, the price tag for eastern span alone had reached a reported $6.5 billion.
In 1996, the cost estimate increased to $1 billion. This was the result of detailed engineering studies conducted during the year or so after the initial estimate was released. Among other things, soil testing in the Bay had revealed that bridge pilings would need to be anchored “deeper into bedrock than expected.
In 1997, Caltrans offered a range of cost estimates for various retrofit designs to the east span. Ultimately the state legislature agreed to fund the bridge to the tune of $1.285 billion. This would have been a straightforward viaduct unadorned by a tower.
In April 2001, the cost had roughly doubled to $2.6 billion. The agency gave two main reasons for the rise. Construction costs were way up with a strong economy—steel and concrete prices, in particular, spiked 18 percent from 1999 to 2000. Caltrans also blamed the two years of delay associated with selecting the final single-tower design.
In August 2004, a new cost of $5 billion was announced, with the tower alone expected to cost at least twice the estimated $750 million. Caltrans blamed the rise on three factors: elevated insurance rates in the wake of 9/11, a 50-percent rise in steel costs related to China’s boom, and greater staff needs owing to so many bridge projects going at once. A state auditor added one more to the list—poor cost management.
In April 2006, a consortium involving American Bridge and Fluor won the tower contract. It was built in China to save money—a decision that carried its own costs when inspectors later found poor welding and busted bolts at key points that required fixing. The current $6.5 billion total is a rough estimate, and that it doesn’t include interest or financing costs.
With those costs included, some expect the total price to double yet again—to $13 billion.
SOURCES – Citylab