Construction magnate Willard Hackerman has offered to finance and build an 18,500-seat arena in downtown Baltimore, civic leaders say, freeing taxpayers from having to foot the bill and significantly increasing the chances that plans for a $900 million convention center expansion and arena will become a reality.

News of Hackerman's offer was made public Wednesday at the annual meeting of the Greater Baltimore Committee, a private business group that has been exploring ways to build an arena that would be combined with an expanded convention center to bolster the city's tourism business and add life to Baltimore's Inner Harbor.

Hackerman, 92, the president and chief executive officer of the Whiting-Turner Contracting Co., attended the meeting but declined to comment. According to GBC officials, Hackerman has been actively involved in planning for the arena and convention center expansion, and hired Ayers Saint Gross, a Baltimore-based architecture firm, to develop the designs unveiled Wednesday.

GBC leaders also showed preliminary designs demonstrating how a 25-story hotel could rise above the arena and expanded convention center. The proposed construction site, owned partly by Hackerman and partly by the city, is bounded roughly by Pratt, Charles, Conway and Sharp streets but does not include the Old Otterbein Church on Conway Street.

GBC officials and others say that Hackerman has the financial ability to raise private money for both the arena and hotel and that he wants Whiting-Turner to build them.

"Mr. Hackerman has pledged to the governor and the mayor that he will engage in creating a private … partnership that will privately finance the arena and the hotel," said Donald C. Fry, president and chief executive officer of the Greater Baltimore Committee. "He sees this as a transformative project that can have a significant impact on downtown Baltimore, and he would like to see that. … It would result in a great revitalization of the area."

Mayor Stephanie Rawlings-Blake, speaking at the GBC meeting, said she was pleased to see private-sector support for the project. "I would like to thank Willard Hackerman for his vision and his commitment to our city," she said.

Gov. Martin O'Malley, also at the meeting, said, "Thank you, Mr. Hackerman."

Much of the project's appeal to Hackerman, Fry and others say, is the combination of an arena and an expanded convention center in one location.

"We have an opportunity for Baltimore that we think is unique on the East Coast — the opportunity to put together a conference center with an arena in a way that would allow us to bring in groups that can't come to Baltimore today," Fry said.

"This concept, combined with the nearby baseball and football stadiums, gives us a chance to accomplish a dramatic transformation of the Inner Harbor into a sports, entertainment and recreation venue that would be largely unrivaled in the nation."

While other cities combine arenas and convention centers, none has united facilities the size of those proposed for Baltimore, said Adam Gross, Hackerman's architect.

The joint facilities would boost Baltimore's convention business by enabling the expanded convention center to accommodate two or three large shows or meetings at the same time — something it can't do now, said Tom Noonan, executive director of Visit Baltimore, the city's convention and tourism agency.

"This would be a hybrid building that doesn't exist anywhere else in the country," Noonan said. "It would give us the opportunity to do a lot of convention business in Baltimore and make us a lot more productive. It would make us really difficult to compete with."

As head of one of the largest construction firms in the country, Hackerman has built many of Baltimore's best-known landmarks, including Harborplace, the National Aquarium in Baltimore and the Meyerhoff Symphony Hall.

An engineer and a 1938 graduate of the Johns Hopkins University, Hackerman also owns commercial properties in Baltimore, including the office tower at 750 West Pratt St. and the Sheraton Inner Harbor Hotel at Charles and Conway streets.

Preliminary plans by Ayers Saint Gross call for a four-level convention center expansion, an 18,500-seat arena over two levels of underground parking, a 500-room hotel, and stores and restaurants facing Pratt, Charles and Conway streets.

The expansion would give Baltimore a convention center with 760,000 square feet of ballroom, meeting and exhibit space, more than twice that of the existing convention center. The estimated price of $900 million to $940 million would make it one of the most expensive projects ever envisioned for downtown Baltimore.

Fry said Hackerman originally indicated that he would fund the construction of a 500-room hotel to replace his 320-room Sheraton hotel, garage and parking lot, which would be displaced by the larger project.

However, as planning progressed, Fry said, he asked Hackerman whether he would be willing to pay for the arena as well. Soon afterward, Fry continued, Hackerman indicated he would be willing to put together a private group to pay for the arena as well as the hotel — eliminating the need for the city and state to issue bonds or identify other funding sources for those phases of the project.

Fry said Hackerman's offer is contingent on the convention center expansion's moving ahead and being connected to the arena to create one project. He said planners would seek city and state funding for the convention center expansion, making the project a public-private partnership.

He said Hackerman's offer to fund the arena privately should make the entire project easier to finance and more likely to move ahead, as funding sources have been identified for more than half the project's total estimated cost.

Based on the preliminary designs, Fry said, the hotel is expected to cost $175 million and the arena $325 million — a total of $500 million that would be covered by Hackerman and his investment group. The convention center expansion, which is expected to cost $400 million, would be the only major phase of the project for which a funding source has not been identified.

Fry said before the GBC meeting Wednesday that he believed the cost of expanding the convention center could be paid for by the city or state or both, by issuing bonds. He noted that bonds were issued to build the original convention center in the 1970s and an expansion in the 1990s. He added that the 1979 wing is paid for and that the bonds for the 1996 wing are to be paid off in 2014.

Fry also said Hackerman's offer eliminates the need for city and state officials to justify the construction of an arena without the city's having secured a professional basketball or hockey team as a project anchor.

He said he believes it would make sense to ask the state to fund an expansion of the convention center, given the state's previous investment in it and in other projects nearby such as the Camden Yards sports complex.

Fry said that the mayor and governor already have requested that the Maryland Stadium Authority conduct a marketing and economic study of the project, which Fry said he hopes will be completed by the end of the year.

With the results of the feasibility study, Fry said, planners can go to the city and state to seek approval to sell bonds to pay for construction of the publicly funded portion of the project. They also may explore other funding sources, such as selling rights to name the building.

Earlier this year, GBC officials said the arena could be completed by 2016 if construction began in 2012. With Hackerman's support, Fry said, the project could be completed close to the timetable outlined last fall — in about four years for the arena and hotel, and an additional three years for the convention center expansion.

The work requires that the 1979 wing of the convention center be demolished to make way for the expansion, but the 1996 wing could remain in operation.

For many years, civic leaders have been looking for ways to replace the 1st Mariner Arena, which opened in 1961 at Baltimore Street and Hopkins Place.

Baltimore banker Edwin F. Hale Sr., chairman of Visit Baltimore and owner of the Baltimore Blast soccer team, which plays at 1st Mariner Arena, said he was pleased that plans now call for holding off razing the old arena until a new one opens.

"I'm happy about that," Hale said of the new plan.

ed.gunts@baltsun.com