Bay Area toll bridge commissioners on Wednesday added $293 million to the $1.7 billion budget for the new Bay Bridge suspension span -- bringing the total for that portion of the project to nearly $2 billion.

The added amount covers extra construction work and other problems that may arise in the complex project, which is scheduled to be completed in late 2013.

Despite the higher costs, the overall estimate for replacing the eastern span of the Bay Bridge remains unchanged at $6.2 billion, and the project still can be finished on time, Bay Area Toll Authority and Caltrans managers said.

The self-anchored suspension span -- featuring a giant tower attached to a cable -- will be the elegant signature piece of the new span between Oakland and Yerba Buena Island. As experts expected, though, it is proving to be one of the most complex sections to design and build.

"We've known for some time there would be some uncertainty in the cost of the suspension span. Now we're able to quantify it," said Randy Rentschler, spokesman for the Bay Area Toll Authority, a partner with Caltrans in the project. "You never like it when you have higher costs, but the good news is we are still within the overall budget for the entire east span."

The joint venture American Bridge-Fluor is the lead contractor.

Included in the $2 billion amount is some $125 million to be used to resolve claims by bridge contractors that must do extra work to complete the eastern end of the suspension span where the giant cable will be anchored.

"This is a very complex part of the bridge," said Tony Anziano, Caltrans toll bridge program manager.

More metal sheets and pieces are needed to fit together in more complex ways than anticipated, putting the project construction behind schedule, he said.

To make up lost time, the public agencies beefed up the budget by $40 million to offer incentives to the contractors to finish the bridge in time to open by Oct. 20, 2013.

The deal also stipulates penalties for missing deadlines.

If the bridge fails to open by Nov. 30, 2013, the contractor is subject to penalties of up to $100,000 per day to a maximum of $125 million, according to a toll authority report.

Also to accelerate construction, Caltrans and the toll authority are spending $20 million for extra space and equipment at the Chinese manufacturing facility where many of the bridge parts are being built and assembled.

The toll authority also increased its contingency fund by more than $100 million to deal with unexpected problems that may come up before the project is finished.

Contact Denis Cuff at 925-943-8267. Read the Capricious Commuter at www.ibabuzz.com/transportation. Follow him at Twitter.com/deniscuff.