TAMPA - If built, a new high-rise proposed for downtown Tampa would be the first new office tower to grace the city's skyline in about 15 years.

But before any such milestone is met, the developers need to obtain construction financing and open before a proposed second new office tower, in the Channel District, is built.

On Thursday, the Tampa City Council unanimously gave initial zoning approval to the downtown office project. The development group behind it said it is serious about plans to build two 50-story office towers on a parcel bordered by Zack and Twiggs streets and Nebraska Avenue.

The area, near the city's Union Station train station and the Lee Roy Selman Expressway, is characterized by a mix of government offices and older homes.

'This location is a critical connection point with everything going on in this area,' said Adam Stein, vice president for development of Union Station Tampa, the Boca Raton-based group that owns the property. The 2.4-acres is near the proposed new Central Park Village, the Channel District and Ybor City.

When the developers initially brought their plans to City Hall in May 2006, they proposed an 850-unit condo complex on the site. But the development group, concerned that the residential condominium market has flattened, has revised its plans so it can build an office tower instead.

The rezoning granted Thursday allows the development group to alter its plans again; the group could build a residential or hotel project instead.

The office tower plans call for 17,500 square feet of retail on the ground floor and a nine-story parking garage with 1,000 spaces.

Twin towers, with 40 floors of Class A office space in each, would contain 840,000 square feet of office space. The height of the buildings would not exceed 540 feet. (Downtown Tampa's tallest buildings, by stories, are Bank of America Plaza and 100 N. Tampa St. at 42 stories.)

City Leaders Like Idea

City council members warmly received the project.

'We're looking at something fresh, something invigorating for that part of the city,' Councilman Charlie Miranda said.

Paul Ayres, director of marketing for the Tampa Downtown Partnership, said the office buildings could attract law firms, accounting firms and major-company headquarters. As more people move downtown to live, Ayres predicted, demand for offices will increase.

Some experts say it doesn't make much sense to build new condominium projects, considering the extended, deep downturn in the residential real estate market.

But it may not make much sense to build new office towers in downtown Tampa, either, say some experts.

Tampa's central downtown business district bears the highest vacancy rates in Hillsborough County. About a million square feet of downtown Tampa's 6.4 million square feet is vacant, according to figures from Cushman & Wakefield, the commercial real estate services firm.

Those vacancies work out to a 16.3 percent vacancy rate for downtown. In comparison, the West Shore business district, the largest office market in the Tampa Bay area, has a 7.2 percent vacancy rate, according to Cushman & Wakefield.

Commercial real estate veteran Robin Bishop, president of Tampa-based Bishop & Associates, said downtown Tampa's vacancy rates have held steady for several years. She said existing buildings have enough vacant space to accommodate expanding and relocating tenants, so it would not be pragmatic to add a massive amount of additional space. 'We need to absorb some of the existing space before it makes great sense to build an 800,000-square-foot totally speculative building,' she said.

Competing For Tenants

If the Union Station office tower were built, it would face stiff competition for tenants.

Trammell Crow Co. is planning to build Prime Meridian Center, a 450,000-square-foot office building in the Channel District of downtown Tampa. The company is promising suburban-style amenities, such as capacious parking decks and expansive floor plans. Developers expect to open Prime Meridian by the end of 2009.

Several other major office projects are on the horizon, or under construction in the West Shore area, including three towers at MetLife's MetWest International mixed-use development, new waterfront buildings from Highwoods Properties, and new buildings near International Plaza from Crescent Resources.

Reporter Ellen Gedalius can be reached at (813) 259-7679. Reporter Dave Simanoff can be reached at (813) 259-7762.