TAMPA — Mayor Bob Buckhorn is thinking about recycling another piece of downtown Tampa from the 1970s.This time, it's the annex behind the John F. Germany Public Library, plus the neighboring auditorium with the clamshell-shaped dome.Once people and the city's mainframe computers are moved out of the annex — a process scheduled to start next week — he said those two buildings could be demolished to create a new piece of vacant city-owned land near the Riverwalk."It's been in the works for about a year now," Buckhorn said this week. "We could potentially put out a (request for proposals) for redevelopment of the site. We could turn it into a park. There's all kinds of things we could do. We haven't decided."Starting next week, about 40 administrative workers from the Hillsborough County's library system will move out of the fourth floor of the main library. That's expected to create space for the Florida history and genealogy collection, which is now on the second floor of the annex.The library administrative staff is being moved to the city-owned historic Free Library building at 102 E Seventh Ave. in Tampa Heights. Buckhorn said he offered the Free Library to the county for the library system's use. The city is leasing it to the county for $1 for 10 years.Once the staff is out, the library will start planning to make space in its main building for the history and genealogy collection, said David Wullschleger, the library system's manager of operations. The children's area now in the annex is expected to go into the main building, too. The Hive, a "maker space" in the annex with tools and other resources that patrons can use to create hands-on projects, is being taken to the library system's branches.In addition to library operations, the annex also houses the city's mainframe computers. Moving those to a new location could take eight or nine months, Buckhorn said.Meanwhile, the library has a separate $260,000 project under way that includes improving the main entrance, adding architectural lights to the outside of the building, installing outdoor seating and upgrading signs, Wullschleger said. The library also plans to improve the fountains in front of the building and add landscaping.Along with bulldozing the annex, which was built in 1975, Buckhorn is talking about demolishing the auditorium, which he describes as "nasty." Consultants who examined the building a couple of years ago said the auditorium cannot host large programs, offers poor access to patrons with disabilities, can't be used after hours and is hard to use in bad weather because it lacks a covered entrance.Plans for change do not involve the main library itself, which sits on city-owned land. A state law dictates that Hillsborough County's main library must be at 900 N Ashley Drive, so moving it would require an act of the Legislature.If Buckhorn did offer the annex land for sale, it would be the latest in a series of outdated or fallow city-owned properties he has tried to put to new uses or to turn into cash. Over the last five years, his administration has:• Launched a $35.5 million renovation of Julian B. Lane Riverfront Park, where the last set of upgrades dated to the mid 1970s. Construction started in July and is expected to take 18 months.• Gone out for bids for a 1-acre parking lot next to City Hall. Officials said in September that the best bid came from New Orleans-based HRI Properties, which has proposed to pay the city $7.5 million for a piece of land that had sat vacant for 20 years. The city still must negotiate a sales and development agreement with HRI, which wants to build a 21-story building with a 223-room Hyatt Centric Hotel, 225 apartments, 7,000 square feet of retail space and a 408-car garage. Construction could start in the third quarter of 2017, with the building to open in May 2019.• Brought in the Columbia Restaurant Group, which spent $6 million to transform the city's old water department pump house next to Waterworks Park into the Ulele restaurant, which opened in 2014.• Attracted a developer to spend $26 million renovating the historic but abandoned federal courthouse on N Florida Avenue so it could be reopened in 2014 as a boutique Le Méridien Hotel.• Sold 1½ vacant acres near Interstate 4 in Ybor City for $660,000. Developers have construction under way on apartments there and on neighboring land purchased from the Catholic Diocese of St. Petersburg.• Sold a third of a block at the western gateway to Ybor City for $792,000 to a partnership between homebuilder Ariel Quintela and BluePearl Veterinary chain CEO Darryl Shaw. The developers have a string of projects under way in Ybor and have proposed a 100-unit apartment complex with an underground garage.• Agreed to reconfigure Cass and Tyler streets next to the David A. Straz Jr. Center for the Performing Arts to create a new city block. The city agreed to sell the land to developers for $4 million, and the City Council approved a rezoning for a 400-foot-tall tower in 2013. Construction has not started on either the road work or the tower.