The skin of the building is built of prefabricated panels installed with an UpBrella track system. This system eliminates the need for a tower crane and does not require swinging any materials or equipment above the adjacent historic buildings or busy streets below. About 75 percent of the panels are prefabricated and delivered, which is not unusual on smaller projects, but not quite as common as would be expected.
“Prefab has a place even in the tiniest of spaces. It doesn’t only have applications on large-scale projects with many repeated elements,” said Sam Rowland, DPR Construction's Project Engineer.
The system uses a bridge crane suspended from the outside of the new structure and a monorail with trolley cranes that circles the perimeter of the new building. The bridge crane lifts panels off the delivery trucks, which are then picked up by one of the trolley cranes and transported with the monorail to its correct location on the building.
The UpBrella system was installed on top of the building, and the team used BIM to plan how panels would be “flown” around the building — through the tight spaces — and installed.
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“We’re flying panels in between the new building and existing buildings, and we’ve only got about 14 to 18 inches to slot panels through,” said Harley Manning, who works with DPR's SPW drywall team.
According to the installation teams, hook up of the panels took two minutes, hoisting took about seven minutes, flying to the appropriate location took up to 13 minutes to the furthest point from the street, and installation took about 10 minutes. In total, less than 10 people are needed to lift, fly, and install the panels.
“On any day, we can install 10 to 13 panels. On some days, we can install up to 18 panels,” Manning said. “Once we get that first layer perfect, we can move a little faster on the second run.”
During that time, DPR’s SPW team, who performed the actual installation, always had hands on the panels, making it much safer than flying the panels overhead with a crane, especially on a busy and crowded street like Broadway.
“One day, when I come to downtown Nashville, I want to tell my sons, ‘Look at the building. I worked on that,’” said Antonio Hernandez with DPR’s SPW team.
