Walk down South Tryon Street these days, and you’re likely to notice people staring through holes in a wall.
Since developer Spectrum Properties and general contractor Balfour Beatty cut holes in the construction wall surrounding the 300 South Tryon office tower site, peering into the ever-deepening pit has become something of a pastime for uptown workers on lunch breaks and schoolkids on field trips.
The perspective is a little different from the bottom, where uptown fades away and workers pour concrete onto the bones underneath the city.
All year, trucks have been hauling dirt out of the pit at South Tryon and Third streets, until they hit a depth of 45 feet below Tryon. Down there, shadows shift as the tower cranes swing overhead, bulldozers clank and smoke and $30 million drill rigs probe even deeper, hunting for bedrock to rest the office tower’s massive haunches on.
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It’s part of a complicated ballet that general contractor Balfour Beatty choreographs each day at the job site.
“This site is very tight,” said Josh McConaughey, senior project manager at Balfour Beatty. About 50 to 60 people a day work on the site now. That will rise to about 1,000 workers a day once the office tower and a planned hotel are both out of the ground and interior work is being completed, McConaughey said.
Here’s a quick refresher on the project: Spectrum Properties is developing the building, with Babson Capital as an anchor tenant leasing the top floors. When it’s complete in March 2017, the 25-story office tower – sitting atop four floors of subterranean parking – will include a fitness center, a restaurant and an extension of Romare Bearden Park running along Third Street to Tryon Street.
On the Church Street side of the site, Spectrum is building a 217-room hotel. The hotel’s brand hasn’t been announced yet, but Maxwell Hanks of Spectrum said it could be as early as next month. The hotel is set for completion in September 2017.
Spectrum isn’t the only company building an office tower uptown. Portman Holdings recently broke ground on a 19-story building next to the Westin hotel, and Crescent Communities plans to start work later this year on a 27-story office tower at Stonewall and South Tryon streets. Beacon Partners is building a seven-story office building on East Morehead Street in midtown.
Workers at 300 South Tryon have spent much of the time up until now excavating the hole and shoring up the sides. They installed a concrete wall along the southern edge of the hole, next to Latta Arcade, to shield the 100-year-old structure’s foundation and try to prevent it from settling.
“It’s more expensive, but better protection,” Hanks said of the wall. Workers also had to install pumps, tanks and water lines to drain the site, since the water table in the area is about 20 feet deep. That’s less than half the depth they’ve excavated down to, so keeping water out is a priority.
Now, most of the work being done is laying a foundation for the building. Workers are drilling holes and sinking 104 caissons for concrete pillars that will support the building’s core. The concrete must rest on bedrock, so the drilling varies from 18 inches to 30 feet below the floor of the pit.
“The majority of work happening now is this core,” said McConaughey. The core will house the skyscraper’s guts: bathrooms, stairs, shafts and machinery for the 15 elevators.
The process moves from one step to another in quick succession. If one part is held up, the whole job can be slowed.
“As soon as one of those is done, our concrete guys come in,” said McConaughey, gesturing at one of the towering, 200,000-pound yellow drilling rigs. Once their work is done, the drills will have to be disassembled and taken out of the pit in pieces – they’re too heavy for the cranes to lift out whole.
The office building should be level with the street again by around the end of the year. Then, once construction of the main floors starts, 300 South Tryon should go up even faster. The goal is to pour one floor a week. The blue tower crane at the corner of South Tryon and Third streets will more than double in size, from its current height of 220 feet to 580 feet, to accommodate the construction.
But before the tower reaches for the sky, all the crucial action is here, down below in the mud where drills poke down and hunt for solid rock.
Gesturing up at the bustle of South Tryon Street, out of sight and earshot, McConaughey pointed out shoring walls, tensioners, rebar, concrete and pumps that the public won’t ever see once they’re buried, but which will support 300 South Tryon for decades to come.
“It’s a different world down here,” he said.
Want to watch the building go up?
You can watch the 300 South Tryon construction camera, mounted above the site, online at https://oxblue.com/open/spectrum/tryon