Unreinforced buildings could crumble in earthquake

More than 1,800 of Portland’s old brick buildings don’t stand a chance in a major earthquake.

Portland's old brick buildings pose risk

PORTLAND, Ore. — Portland’s old brick buildings don’t stand a chance in a major earthquake. 

“These buildings were never designed to withstand seismic shaking,” warns Carmen Merlo, director of Portland’s Bureau of Emergency Management.

Over the years little has been done to identify the most dangerous buildings in Portland or require property owners to retrofit them. Many residents have no idea the walls around them are at a higher risk of collapsing in a major earthquake.

Engineers estimate there are roughly 1,800 of these so-called “unreinforced masonry buildings” in Portland, but they don’t have an exact number. The last survey was conducted in the mid-1990s.

“All of these red dots represent unreinforced buildings in the city of Portland,” explained Amit Kumar of the Bureau of Development Services. The senior structural engineer laid out a map – it was covered in overlapping red dots – identifying old brick buildings.

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“You can see a big concentration of these buildings in the central city, downtown, Northwest Portland, the Pearl District areas,” Kumar said.

While newer buildings should be okay in a major earthquake, engineers warn Portland’s old brick buildings will likely crumble because the walls are not reinforced.

These buildings include businesses, schools, theaters, churches and apartments.

In an earthquake, the brick walls can pull away and the floors collapse. The decorative piece rising above the roof, called the parapet, can also topple over.

“There are a lot of these buildings. Unreinforced masonry are very vulnerable in an earthquake,” said Kumar. “Even in a smaller earthquake they can pose a lot of risk.”

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You don’t have to look far back in Oregon’s history to see an example of crumbling masonry buildings. The 5.6 magnitude “Spring Break Quake” in March 1993 damaged brick buildings in the Salem area. The bricks at Molalla High School were also damaged.

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Very few of Portland’s old brick buildings have been retrofitted for one simple reason: it’s expensive.

“We’re talking anywhere from $25 to $40 per square foot,” estimates Walter McMonies of Portland. The property owner spent two years and hundreds of thousands of dollars to retrofit the Trinity Place Apartments in Northwest Portland.

“You have a moral obligation to your tenants.  If you’re going to be renting to people you probably need to do something,” said McMonies. 

The seismic upgrades at Trinity Place included securing floors and roofs to the building walls, and bracing the parapet. The upgrades won’t prevent all damage from an earthquake but should allow people to evacuate.

“The first priority is what they call life safety,” said McMonies. “Can we get the people out of the building safely?”

Emergency managers would like to require seismic retrofits for Portland’s most dangerous buildings – similar to laws in California.

“They’ve already adopted a mandatory retrofit for unreinforced masonry buildings,” explained Merlo, the director of emergency management.  “In many cities, like San Francisco or Los Angeles, there are very few, if any, unretrofitted buildings still in existence.”

City planners are working to figure out exactly which buildings need to be fixed in Portland. They hope to introduce an ordinance in 2016 requiring owners to retrofit their buildings. There could potentially be grants, loans or other incentives to help offset the cost.

“We think this is the right thing to do,” said Merlo.  “Not only to save lives, to save property, but also to ensure the historic nature and character of the city is preserved.”

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