OLYMPIA – Many Washington public schools are at risk of serious damage in an earthquake, a new study ordered by the Legislature said.
“Washington state has many older school buildings built prior to the adoption of modern seismic safety codes,” said the study, released Tuesday by the Department of Natural Resources.
Certain types of construction are particularly vulnerable to collapse in an earthquake and those risks “should be mitigated as soon as practical,” the study said.
For many, it would be cheaper to upgrade them now than to repair them after a quake, the study said. But for one building studied in Spokane, Adams Elementary School, shoring up the 1910 building against the relatively low risk of a quake might not be cost-effective, researchers said.
In 2017, the Legislature gave the department $1.2 million from the state’s capital budget to study the quake risks for public schools. The state has 4,444 public school buildings; the department studied a sample of 222, or 5%, with a more detailed construction and seismic analysis of 15.
The schools were selected based on a mixture of location, proximity to known fault lines, type of construction and age, said department spokesman Joe Smiley.
Washington has a wide mix of geologic formations that can produce the three different types of earthquakes, the report said. Although significant quakes are more common in Western Washington, which has had four major quakes since 1946, Eastern Washington is not immune. Quakes near Chelan in 1872 and Walla Walla in 1936 also caused significant damage.
“The presence of all three earthquake sources and the relatively high likelihood of having another earthquake in the future, in addition to the high population density in areas where these earthquake hazards exist, increases the seismic risk for our state,” the report said.
About 70% of the state’s schools are in high seismic risk areas, the report estimated. The seismic areas, type of construction and age for each of the 222 buildings were studied across the state. For Spokane Public Schools, the researchers looked at Adams and Audubon elementries, and the Libby Center. Other schools near Spokane included Chattaroy Elementary in the Riverside School District, Newport High School and Dayton High School.
The main building for Adams Elementary, an unreinforced masonry structure built in 1910, is one of the oldest buildings on the full list and the oldest among the 15 evaluated for possible costs of a seismic upgrade. Unreinforced masonry is one of the construction methods most at risk in a quake, and the cost of providing the school with structural upgrades, as well as upgrades for fire protection equipment and mechanical improvements, was estimated to be $1.1 million to $2.1 million.
But Adams is in an area at low risk of seismic activity and is one of only two schools studied for which the cost of repairing the damage to the building might be less than the seismic upgrade.
The Dayton High School gymnasium, however, a light steel-frame structure built in 1965, might be one of the best bets for a seismic upgrade, even though Dayton also is at a low risk for an earthquake. It could be upgraded for $50,000 to $95,000, engineers estimated, while fixing the damage could be more than 10 times that amount.
That’s because the cost of repairing a light steel-frame building is so high, Smiley said. A light steel-frame building in the Grand Coulee Dam School District was the only other one in the study with such a high ratio of upgrade-to-repair costs.
The report doesn’t say school districts have to upgrade their buildings. Instead, it’s giving them “actionable information” on the conditions of their buildings, and an idea of the cost to upgrade the ones that are most at risk.
The 2019 Legislature set aside another $2.2 million for the current biennium to study another 300 to 350 buildings, Smiley said.
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