Nashville courthouse built with little room to spare

The Beverly Briley Courthouse, a $39.2 million building that will house Nashville's criminal courts, has contractors in a tight spot. The building covers about 41,600 sq. ft. of a 54,000-sq.-ft. site and is surrounded by a major power substation, a building and two streets. "The only way we can get precast up and over it is with a large crane," said Chris Winfield, assistant project manager for subcontractor Gate Precast Co. of Ashland City, Tenn. The crane is situated on the east side of the job and must lift the precast - some of which weighs nearly 16 tons - to the building's north side.

Gate Precast has produced 752 precast concrete panels. About 90 panels are already up on the north and east sides as steel is being erected on the remaining two sides, Winfield said. The largest panel is just over 11 ft. by 31 ft. Panels covering columns average 8 ft. by 20 ft. and weigh about 8 tons on the lower part of the building and 11 tons to 12 tons near the top.

"Lady Justice will also be made of precast in a relief sculpture. Weighing 25 tons, she is being cut into five sections to spread the weight over five panels," Winfield said.

The tight space has slowed the installers from Precast Services Inc. of Columbus, Ohio. They get about eight panels up daily, compared to 12 to 15 panels on a more open site, Winfield said. Their crane operator, however, must lift the panels up and over the building, guided by two-way radio, and stay away from the substation that's a few feet from the building. "The guys on the building - especially with the size and weight of these pieces - have to really trust the crane operator," he said. "We knew it was a small site but had no idea it would be this small," said Derek Bell, project manager for general contractor Ray Bell Construction Co. of Brentwood, Tenn.

The six-story, 245,000-sq.-ft. building will have 16 courtrooms and will connect to the nearby jail with a sky bridge made of concrete masonry units, reinforcing steel and a precast concrete panel exterior, said Lillard Teasley, principal of Teasley Services Group LLC in Nashville, the project's structural engineer. The prisoners will go to a main holding area and are locked in elevators for transport to holding cells near the courtrooms. Judges, the public and prisoners will move through the building via three separate corridors, said Rick Macia with Spillis, Candela DMJM of Coral Gables, Fla., associate architects.

Courtrooms get ballistic armor at the bench and emergency buttons are in the courtrooms, judicial offices, clerks' counters and public counters for clerks' offices, he said. Originally to be built in thirds, the structure is now going up in 14 sequences, which helped shave two months from the timetable. "It's like a big puzzle," said Brantley Gilmer, project manager with structural steel supplier Wylie Steel Fabricators of Brentwood, Tenn. Wylie Steel is supplying 1,275 tons of structural steel, 285 tons of decking and 13 tons of metal joists, Gilmer said. "Each piece has a number and the erection crew (Group Steel Erectors of Dickson, Tenn.) knows how they work," he added. The site itself was an early challenge. The rock underneath has natural fissures and fractures, as well as cracks from earlier blasting. A spread footing foundation wouldn't work in all areas so micropiles were substituted, said Jeff Kuhnhenn, project architect at Gresham Smith and Partners of Nashville. Bell and Teasley worked out a solution. "Teasley came up with a solution," Bell said. The 277 micropiles are 7-in.-diameter, drilled and grouted. Most are sunk 15 ft. to 20 ft. deep, some 50 ft. to 60 ft.