City Hall: ‘toast’ in a big quake
February 22, 2008
If an earthquake of magnitude 7.0 or higher struck Park City, it’s best that someone not be inside City Hall.
A temblor that size could leave the building in ruins, a key reason why the Park City government plans an extensive renovation of the building later in 2008.
"This building is toast," Chief Building Official Ron Ivie admits when he talks about the possibility of an earthquake of at least magnitude 7.0 shaking the area.
Earthquakes of lesser severity could threaten the building, he says. The Marsac Building, a New Deal-era structure perched above Swede Alley, would be "at some risk" in a close by magnitude 5.0 earthquake, he says. An earthquake of magnitude 6.5 would cause "serious damage," according to Ivie.
He cautions that other factors in an earthquake would contribute to whether the building falls, and Ivie says he cannot say with certainty what magnitude earthquake would destroy the building.
His comments come after an earthquake struck rural Nevada Thursday. People in the Salt Lake Valley felt the shaking, but authorities in Park City and Summit County say they did not receive reports about the earthquake.
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Ivie and others have long been concerned about an earthquake hitting locally, and the area’s seismic activity is well understood. There have been occasional earthquakes in the region.
Ivie years ago, before the 2002 Winter Olympics, condemned City Hall based on his assertion that the building is susceptible to earthquakes. Since then, city officials have mulled plans to strengthen the building to make it safer, resulting in the blueprints for the upcoming renovation.
The building, which was a schoolhouse before it was turned into the city offices, features outside walls made of unreinforced masonry and a steel frame.
After the renovation, what are known as "shear walls" will be reinforced with steel rebar. That, Ivie says, will distribute the energy from an earthquake into the shear walls. The brick exterior of the building will remain.
Afterward, Ivie expects the building would not collapse in a magnitude 7.5 earthquake, although it might fail structurally and need to be torn down.
"The odds are about one in a 200-year period that this building will have that problem . . . You sort of play the odds," Ivie says.
The renovation of City Hall is scheduled to start in June. Officials have set aside $5.3 million for the project. The building will also be made more accessible for handicapped people, new plumbing and electrical systems will be installed, and a heating and cooling system relying on the Earth’s internal temperature will be put in, among other upgrades.
Meanwhile, at the Park City School District, Steve Oliver, who oversees construction, says school buildings were constructed to meet the earthquake standards in effect at the time the buildings went up.
"They are as safe as the code required they were built under when they were constructed," Oliver says, acknowledging he is unsure how many School District buildings meet the current standards.
The renovation of Park City High School meets the earthquake standards, he says.
"Buildings are built to the code . . . Nobody can do better than that," Oliver says.
Utah lawmakers are considering a bill that would require the earthquake risk be evaluated at each public school in the state. A House of Representatives committee favorably recommended the legislation, but the full House has not voted. Neither of the two local state representatives are on the committee that recommended in favor of the bill.