Charlotte, North Carolina currently ranks as the third-fastest growing major U.S. city, with growth on the upswing for over a decade. South End is a particularly booming Charlotte neighborhood, home to some of the city’s best restaurants and nightlife, the 11-mile-long Rail Trail public trail and the Blue Line light rail, which brings visitors in and out of the area.
Adding even more clout to the district is the city’s newest retail and office tower, The Line. The recently completed 16-level building was designed to bring the community together and foster connection among residents and visitors. It houses 298,600 sq. ft. of office space above 304,500 sq. ft. of structured parking, and provides breathtaking views of Uptown Charlotte. The ground floor includes 24,400 sq. ft. of retail, restaurants and a brewery.
The Charlotte branch of DPR Construction performed the concrete scope of The Line, which included 25,000 cu. yds. of concrete and 4,000,000 lbs. of rebar.Minnich Mfg.
The Charlotte branch of DPR Construction performed the concrete scope of The Line, which included 25,000 cu. yds. of concrete and 4,000,000 lbs. of rebar. Unlike a traditional office building, much of the concrete was left exposed, prompting DPR to focus heavily on a quality finish.
“Our team enjoyed working through the unique elements of this project,” said Paulie Estrada, concrete superintendent, DPR Construction. “The new structure is going to create a space for the community, and visitors, to shop, unwind and see new views of the city.
“Building The Line didn’t always come easy, though,” he adds.
Working through challenges
To break up the 16-level structure between parking and retail space — and add architectural appeal — a sky lounge was included on level eight. Not only did this create a unique look for The Line, it brought challenges, too.
Starting on the ninth level, The Line includes two towers that sit on top of the sky lounge, with the tower floors extending past the face of the structure and parking deck. This posed a challenge due to how the floor defies gravity.Minnich Mfg.
The main core of the structure (shear walls) and columns are an integral part of the structure and were crucial to get right the first time. The vertical concrete elements start at ground level and extend all the way to the ninth floor. Not only are they important to the structure, but the 17-ft. shear wall is exposed in the sky lounge, creating a center piece of the design.
“It was tough to make sure we consolidated the concrete well because there was a lot of rebar inside the walls and columns,” said Estrada. “These were critical pours. The walls were very high, making it hard to look down the side of the column and be confident that we were vibrating everything to our standards.”
Choosing the right equipment
To eliminate the imperfections in the pile caps, columns and barrier walls, DPR Construction used four Stinger electric flex shaft vibrators from Minnich Manufacturing on the jobsite.
The Stinger is a 14.5-lb. double-insulated universal motor that can drive the full line of Minnich vibrator shafts and heads from ¾ to 2½ in. Available in a 15-amp (115-volt) version, it offers a speed range of 10,000 to 13,000 vpm to meet today’s concrete placement challenges.
The unit is equipped with a durable protective frame, which extends vibrator life, with urethane end caps that absorb shock while supporting easy to grip handles. A fully adjustable harness and compact size allow for easy carrying around the jobsite and access into small spaces.
The vertical concrete elements start at ground level and extend all the way to the ninth floor.Minnich Mfg.
Estrada also appreciates the unit’s dependability. “Before the Stinger, I was using a different brand and had problems with it day after day. I even had situations where I had to rework the concrete after the vibrator didn’t consolidate as needed,” he stated. “The Stinger has minimized issues and re-work dramatically. It works efficiently and can handle the workload we put it through day in and day out on the job.”
