Mayor Nutter and Convention Center Authority officials reiterated yesterday their support for the Convention Center expansion and said they hoped bids due today would not break the project's budget.

Nutter and authority chairman Thomas "Buck" Riley emphasized that the true impact of the final construction numbers to be announced today will not be known for several weeks.

Once bids are opened, the apparent low bid will have to be analyzed to ensure it meets specifications. The contractor's plan for minority-subcontractor participation must also be scrutinized.

The $700 million project is now expected to be at least $90 million over the original budget because of soaring construction costs.

When the first construction bid, for the steel superstructure and concrete foundation, came in 20 percent over budget in May, officials reestimated costs at potentially $90 million more than the $700 million set in 2006.

"My hope and expectation is that we are going to be able to build one of the best expanded convention centers anywhere - and stay within our cost constraints," Nutter said.

"I don't want to speculate on the 'what if,' because we haven't gotten to that point," the mayor said. "We'll know a lot more in about three weeks, when we are dealing with hard data."

Amid optimism that the expansion will be built, the Convention Center Authority board said goodbye to its president and chief executive officer, Albert A. Mezzaroba, who is returning to private law practice.

Mezzaroba, 43, had been a member of the authority's board before becoming chief executive in early 2003, at the time Nutter, then a councilman, became chairman of the Convention Center board.

Mezzaroba said he planned to take "a little time off" and then practice law. He said he had no immediate plans to join a firm.

Nutter came to Mezzaroba's last board meeting to offer praise - and a few stories.

"It was just a wild time," Nutter said. "We certainly had both challenge and controversy. People did give us a shot. The end result is, 51/2 years later, this Convention Center is at a much different and better place."

Gov. Rendell said last week that if the final construction bid was way over budget and it appeared "we cannot go fowrward, we've simply got to pull the plug."

But Rendell said he had a plan to try to salvage the project, if the bids are "way over."

What is the breaking point? No one is saying. Rendell said the project was "achievable" if the cost is $790 million - which is $90 million more than planned in 2006.

The state will provide $700 million from slot-parlor revenue for the expansion. The $90 million shortfall would come from an increase in the city's hotel tax, if approved by Council.

Surging prices for steel, copper, reinforced concrete, and other construction materials, along with diesel fuel, have driven up costs.

Board chairman Riley said he would "welcome" any ideas from the governor, but noted the city would be an "also ran" among the nation's largest convention cities if the expansion is stalled.

"This isn't just standing still if we don't build this addition," Riley said. "We'll go backward, as a city and as a destination city."

Jack Ferguson, the Philadelphia Convention and Visitors Bureau's executive vice president of conventions, told the board $1.3 billion worth of large convention business is booked in the expanded center in years 2011 and beyond.

Carl Singley, authority board member and former Temple Law School dean, said the expansion was "too important to the economic well-being of the region not to happen."

"I have no reason to believe the numbers won't be within reason," Singley said. "I'm absolutely optimistic that it gets built."

Contact staff writer Linda Loyd at 215-854-4822 or