Once the excavation of the new arena is complete, these ‘Y’ columns will be retrofitted, continuing down the 60 feet to the new arena’s base, where they will be planted to again support the roof.
Once the excavation of the new arena is complete, these ‘Y’ columns will be retrofitted, continuing down the 60 feet to the new arena’s base, where they will be planted to again support the roof.

The Seattle Center arena has been an important fixture for the large crowds that conventions, music concerts and sporting events have drawn to the property for more than 50 years.

When it came time to address rebuilding the arena into a bigger and better venue, keeping the iconic roof was a high priority, said Ken Johnsen, construction executive with Oak View Group .

“The owner(s) probably stepped back very early in this project and said, ‘How do we save that iconic roof,” he said, “and how do we build the best arena for hockey, for concerts and the Storm and, yes, the Sonics when they come back.’” Johnsen said Oak View Group is currently within its revised $930 million budget — the original estimate had been $650 million — and the developer also plans to keep its schedule for completion by late summer 2021.

“This is not a renovation,” Johnsen said. “It’s saving the iconic roof, but this is a brand-new arena being built, and you can see — the old arena is gone. There’s really nothing left except for that roof. We are holding that roof up temporarily. We are digging down to build a brand-new arena, the best in the country.”

The Seattle Landmarks Preservation Board actually set conditions that the original glass windows and iconic roof be retained in the project. The windows have been removed and catalogued for their eventual return.

OVG will excavate at least 600,000 cubic yards by the end of the year, digging at least 60 feet below street level, eventually doubling arena’s original size.

Preserving the original roof hasn’t been as simple as Johnsen originally thought.

“Clearly, the challenges of that temporary roof were underestimated early on in the project, but starting early this year, really smart engineers and contractors got together and said, ‘OK, if we are going to hold this (44 million) pound roof up, how do we do that while we build this building…’ It was a bit more complicated than what we thought, but we are holding it up now.”

To ensure it would stay up while the construction crew builds beneath it, the familiar capstone roof was pushed up by 100 million pounds of pressure from temporary support structures.

Keeping the roof up takes 70 temporary roof columns and a shoring tower in the roof’s center.

The arena’s 20 permanent ‘Y’ columns and four buttresses will support the weight of the roof once they are retrofitted for the new arena. The current ‘Y’ columns will be sliced to accommodate the build while the temporary towers/columns hold up the roof. The ‘Y’ columns will then be extended down to the base of the new structure

Currently, more than 100 people are at work beneath the roof, and that number will increase tenfold in a year’s time.

Since this project has already hampered neighborhood activities, Johnsen told the Queen Anne News he appreciates the community’s patience.

“This is a construction project, you know, ‘til the summer of ‘21,” he said. “We’re working really hard with the surrounding residences and businesses and all the tenants of Seattle Center to say, ‘Look, pardon our dust, so to speak — we’ve got a big project to build.’ So far we’ve been so, so pleased with the neighbors, who understand this is something we are going to go through together, and in the end we are going to have this fantastic arena and open space.”