The weight of ANC’s kinetic scoreboard planned for Wells Fargo Center requires upgrades along the roofline. (Courtesy Wells Fargo Center)

The roof retrofit issue isn’t restricted to stadiums. Big league arenas are strengthening their existing roof structures to meet the demands of high-tech videoboards and extravagant touring productions. 

“Arenas built over the past 15 years are really struggling to keep up with where concerts are going these days,” said Bart Miller, a principal with Walter P Moore, a structural engineering firm for sports and entertainment venues. 

A decade ago, arena rooflines were designed with 120,000-pound rigging capacity. Now, many concert tours carry 200,000 pounds of equipment, and any rigging system under that number is not adequate for what’s going on in the entertainment industry, Miller said.

“The loading is getting heavier and more widespread, distributed over a much larger area than it used to be,” he said. “Some loads are dynamic and move around with stages and beams, and a lot of these existing roofs weren’t designed to accommodate these kinds of shows.” 

In an arena setting, the retrofit typically involves reinforcing steel trusses and connections. The cost for those modifications varies depending on the frequency, magnitude and location of those reinforcements, ease of access and scheduling conflicts with events, Miller said.

 The typical cost for those retrofits runs about $100,000, he said.

Bigger and heavier center-hung videoboards are also driving the retrofits. Walter P Moore has two clients, Wells Fargo Center in Philadelphia and Gila River Arena in Glendale, Ariz., tied to new center-hungs. In both cases, rigging grids are being reinforced to handle concert tours as well, Miller said.

“In Philadelphia, the new center-hung can expand from a roughly square-shaped board … to a large rectangular board that you see in other venues,” he said. “The LED is much lighter per square foot, but the technology and other systems added to the board makes it much heavier.” 

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Roof retrofit grows into a top priority