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The state Capitol is ready to rock and roll.
In a ceremony Monday, dignitaries in hard hats released the final stabilizing pier in a more than $60 million seismic retrofit begun in 2004 that would allow the 90-year-old symbol of Utah government to shimmy rather than collapse in an earthquake. The total cost of the ongoing Capitol restoration is projected at $212 million.
The couple dozen engineers, architects and restoration workers were celebratory, despite the ceremony taking place in the Capitol's cavernous concrete-reinforced basement, what Rep. Wayne Harper, R-West Jordan, referred to as "the bowels of the Great Lady of Utah."
Harper, Senate President John Valentine and House Minority Leader Ralph Becker used a golden wrench to unthread nuts the size of a child's fist from the final plates holding the so-called isolators in place. The massive seismic dampeners had been locked in place until foundation work was completed.
Each isolator contains a stack of yard-wide disks of rubber, stainless steel and lead that would allow the 84,000-ton building to slide "like a brick on rollers" to absorb tremors, said structural engineer Jerod Johnson.
Workers already had removed the locking plates from the other 265 subterranean isolators and as soon as the four plates came off the last pier, which supports a section of the rotunda, the Capitol was free to roam two feet in any direction to shrug off an earthquake of as much as 7.3 magnitude.
That is the maximum predicted earthquake in Utah, said Johnson. "We could call that a doomsday event." The Northridge, Calif., earthquake in 1994, by comparison, registered 6.9 on the Richter Scale.
With the most important aspect of the retrofit finished, only about 20 percent to 25 percent of the work at the Capitol remains. And that's mostly finishing work, said Capitol architect David Hart.
The project should be wrapped up, on time, by late November or early December in time for the next Legislative session.
Hart said it is customary to throw a "topping-out" party when steel workers place the final beam in a high rise. Because the most important goal of the Capitol restoration is to protect it from earthquakes, "We are having a bottoming out - or a release-the-Capitol - party," Hart said.
"Amen," said state heritage preservation officer Wilson Martin as the last nuts were removed, adding, "Before we have an earthquake." Until the isolators were freed, the Capitol was actually at higher risk to damage from tremors.
While the ground rocks during an earthquake, the stabilization system would allow the Capitol to waltz for about four seconds - two seconds in one direction and two-seconds back - before settling back on its isolators.
The science of seismic stabilization still is being developed, Hart said, and the Capitol - which is less than 400 feet from the Wasatch Fault line - will become an experimental lab "when we have an earthquake."
Workers will soon install motion-measuring instruments that will be monitored at the University of Utah geology department.
"When we have an earthquake we will be able to see the effect on the building." Hart said. The instruments would measure the Capitol's movement during the tremors - what engineers call "scragging;" its maximum acceleration and how it settles back on to its supports.
"We will be able to use that information to improve the next building and the next," Hart said.