Expert: Bertha's Woes Are No 'Big Dig'

Feb 18, 2014

The prospect of taking the State Route 99 tunneling machine known as Bertha offline for as much as half a year is not good news for the company operating it. But one Seattle tunneling expert says it could be worse.

“It’s really a problem with the machine itself. I think it’s something that can be repaired,” said the University of Washington’s Joseph Wartman. “And I think in a couple of years when the tunnel is open, people will have forgotten about this.”

Wartman is an associate professor of engineering and an expert in underground construction. He even did some work on Boston’s infamous Big Dig. There, a number of the really fundamental problems that keep engineers up at night actually happened. He said there’s no sign of anything that serious here.

“There’s no damage at the ground surface. There isn’t damage to the buildings. And I don’t think there's anything that would suggest that the integrity of what they built so far is threatened,” Wartman said.

Wartman says not all tunneling operations have problems; look at the Sound Transit linkage between the U-District and Capitol Hill, for instance. But the SR 99 tunnel project is pushing the mechanical limits of what’s possible in underground construction. He says with the world’s largest-diameter tunnel boring machine making her maiden voyage, he’s not surprised she’s hit some snags.