ST. PETERSBURG — A South Florida company has started work on a 218-unit apartment building in St. Petersburg's increasingly vibrant Edge District. The five-story Bainbridge 930 Central Flats on Central Avenue will have studio, one- and two-bedroom apartments renting for about $1,160 to $2,500 a month. They will be in the heart of a once-tired area on the fringe of downtown that is being transformed by new bars, shops and restaurants.They also will be near Tropicana Field, the recently relocated Chihuly Collection and a Publix that is under construction."We like to target millennials and young professionals, and they have a tendency nowadays to want to live in locations where they can just walk out their door and go to all of the entertainment venues," Bob Thollander, vice president of development for the Florida region of Bainbridge Cos., said Friday.Thollander, whose company has other apartment projects under way in Ybor City and Brandon, said there is still a strong demand for high-end rentals in downtown St. Petersburg even though several other complexes have opened recently or are nearing completion. "All of the apartments we looked at were 100 percent occupied with very high rents," he said. "It just seemed like a natural place."Wellington-based Bainbridge bought the vacant tract for $5 million from developer Jonathan Daou, who bought it two years ago for $1.65 million. Daou originally intended to build stores and a parking garage, but those plans fell through."We had multiple offers" for the site, Daou said. "We are not really ground-up builders, so we got a good offer and wanted to fill in the block because we don't want to see empty land in that district."Daou still owns much of the rest of that block of Central, which he envisions as part of a "walkable district" with enough places to dine, shop and browse to compete with the Beach Drive area. He recently bought the nearby Shirley Ann Hotel, now a residential hotel with mostly older occupants."It's not a high-end hotel by any means," he said, "but we aim over time to clean it up and upgrade it."Meanwhile, Daou said he is moving ahead with plans to redevelop the old North Ward Elementary School on Fourth Street N into a restaurant, shops and yoga studio."The permits have been approved, the contractor chosen, the construction financing is fine,'' he said. "So in less than 30 days, you will see activity there."Contact Susan Taylor Martin at [email protected] or (727) 893-8642. Follow @susanskate.