The current center, which was completed in 1993, now spans from 11th to 13th streets between Arch and Race streets. The expansion will stretch another two Center City blocks to the west from 13th to Broad streets. In addition to raising the number of exhibit halls from four to seven, it will add 60,000 sf of ballroom space and another 72,000 sf of meeting rooms.

Four years ago the expansion was projected to cost $464 million. The tab rose to $632 million a year ago, and this year's earlier estimates began to approach $800 million, but a spokesperson for the Authority tells GlobeSt.com the design plan was modified to keep it within the $700-million budget.

At that, it is the state's largest capital expenditure ever. The state legislature approved $400 million for the project in 2003, and added $300 million in the 2005-2006 budget. The money is to come from tax proceeds from the state's slots venues.

In mid-November 2005, the state provided a $16-million down payment to cover the design and construction documentation. At that time, as GlobeSt.com reported, Gov. Ed Rendell stipulated that controls be in place to ensure that the project is delivered on time and within budget.