TAMPA - Bob Abberger says he has the cure to fight the exodus of companies from downtown Tampa to glitzier buildings in the West Shore district and the suburbs: a 20-story, 450,000-square-foot office tower and 300,000-square-foot hotel erected in the shadows of the Channelside District.

Abberger, managing director of real estate firm Trammell Crow Co., filed zoning papers Thursday for the $350 million project that could encompass four city blocks north of the Crosstown Expressway. The project includes the main office tower, a separate tower to house a 350-room upscale hotel and a parking garage with 1,200 spaces.

He predicted the project will help the struggling Tampa economy.

"It's going to be a huge generator," he said. "It can be a game changer for downtown."

Abberger acknowledged that the downtown office vacancy rate hovers at about 20 percent. But he said if you strip away the lesser quality buildings, the vacancy rate is in the single digits.

The office tower would also attract tenants because it will be the first new one built around downtown in more than 15 years, he said.

"You have the best, then you have the rest," Abberger said. "I know what it means to set a new standard."

Abberger has not secured financing for the project. He expects backers to come on board after tenants agree to leases. Talks are under way with high-end hotels to anchor the project, which could break ground late next year, Abberger said. Construction on all buildings could be completed in 2014.

The proposed development abuts the University of South Florida's new $30 million Center for Advanced Medical Learning and Simulation. The medical training complex, scheduled to open in January, is the first piece of an expanded downtown presence for the university. The medical complex alone is expected to attract enough out-of-town doctors to fill a 95-room hotel.

The zoning request will go before the Tampa City Council in December and for final approval in January. The property, owned by Naples-based Collier Enterprises, is used currently as a parking lot and is bordered by S Florida Avenue, E Brorein Street, S Morgan Street and E Whiting Street.

Although the office tower will be half the height of Tampa's biggest skyscrapers, the proposed building's 28,000 square-foot footprint will be nearly 10,000 square-feet larger than other towers. Businesses that have left downtown want their employees all on one floor, not scattered across several, Abberger said. He plans to seek a LEED certification for energy efficiency in the tower.

Two commercial real estate experts in the bay area have differing opinions on the project.

Lee Arnold, chief executive of Colliers International in the bay area, said building the hotel first is a good idea because the USF medical facility will fill up many of the rooms.

By the time the office tower opens in 2014, the economy should be on better footing, which will help attract tenants, he said.

"It's an ideal track of land for that use," Arnold said. "I think he can be successful. Tenants will flock to a quality product."

Ed Kobel, president of Tampa-based DeBartolo Development, said office space is in high demand in New York, Chicago and Los Angeles, but not Tampa. His company scours the country for distressed properties with low prices.

He called Abberger's plan a great idea, but said "the future demand for office space is weak."

The building's proximity to the Channelside entertainment district, Abberger said, will provide something that other downtown towers can't: less congestion and less traffic.

The project is similar to the Prime Meridian Center, a 20-story building, which Abberger wanted to build in 2007 across from the St. Pete Times Forum before the real estate market soured the following year. He pointed to his spearheading the Marriott Waterside, the luxury hotel his company completed in 2000 despite a chorus of doubters. The 700-room hotel, the city's largest, made a lot of money for his company, he said.

Abberger once chaired the Greater Tampa Chamber of Commerce's Committee of 100, the chamber's business recruitment arm. Mayor Bob Buckhorn recently appointed Abberger to the city's Economic Competitiveness Committee, a group tasked with streamlining city development rules.

Abberger is optimistic about Tampa's economy and future.

"Now is the time to stop looking down and start looking up," he said. "I wouldn't be doing this if I didn't have the confidence."

Mark Puente can be reached at mpuente@sptimes.com or (727) 893-8459. Follow him at Twitter at twitter.com/markpuente.