Seismic shift in Capitol project
Ceremony marks transfer of building load to withstand a 7.3 earthquake
"We have the comfort of knowing we can't lose this building, we can't lose this treasure," said House Minority Leader Ralph Becker, D-Salt Lake, a member of the Capitol Preservation Board in charge of the four-year, $200 million retrofit and renovation project set for completion in November.
Without the series of base isolators, a sort of shock absorber intended to allow the 80,000-ton granite structure to sway rather than split apart in an earthquake, Becker said significant seismic activity would have been able to "just corkscrew the building into rubble."
Becker was among the ceremony participants, although the building's weight was actually shifted from unreinforced concrete columns to the 265 base isolators and 15 similar devices known as sliders over two days last month, April 17 and 18.
It was during that process that the Capitol was most at risk, according to structural engineer Jerod Johnson of Reaveley Engineers, calling an earthquake at that time "the worst-case scenario."
Especially since the Wasatch Fault is located just 200-300 yards from the building. "We're as close as we can possibly be," Johnson said, noting the Capitol can now withstand a massive 7.3 magnitude quake — the much-feared "Big One" predicted to strike anytime.
Even though it's now resting atop the new base isolation system instead of the original concrete columns poured more than 90 years ago, the Capitol won't budge unless there's earthquake activity, Johnson said.
The first base isolator was installed in May 2005, and since then, everyone associated with the Capitol reconstruction has been waiting to mark the completion of the most critical part of the project.
David Hart, executive director of the Capitol Preservation Board, said Monday's ceremony in the bowels of the building would replace the typical "topping off" ceremony done when the highest point of a structure is completed.
This ceremony, Hart said as he handed Senate President John Valentine, R-Orem, a golden wrench, was to symbolically "release the Capitol" from being bound too rigidly to the ground.
Of course, the project isn't finished yet. Hundreds of workers continue to put the finishing touches on the portion of the stately structure that, unlike the base isolators, will be visible to the public such as the House and Senate chambers.
Utahns will have their first opportunity to see the results of that restoration effort during an open house scheduled from Nov. 19 through Dec. 1. The Capitol is set to be rededicated on Jan. 4, 2008, Utah's statehood day, and ready for the 2008 Legislature.
E-mail: lisa@desnews.com
You can be the first to comment on this story.