Earthquake News

After Nisqually quake, need to shore up buildings persists

MRP Engineering President Mark Pierepiekarz, who co-authored a 2005 analysis on the likely effects of a shallow magnitude 6.7 earthquake, said, "That dated construction is what we're most concerned about.

Damage to brick structures that have not been reinforced in decades can be "catastrophic", according to Pierepiekarz. However, due to the high cost of seismic reinforcing, most property owners don't undertake it until they're rebuilding a structure.

Public entities are also having difficulty funding reforms. After years of planning and discussion, construction on two of the most notable projects — the need to replace the fragile Alaskan Way Viaduct and the Highway 520 floating bridge — is just getting underway.

The Puget Sound region is better prepared today than February. 28, 2001, when an earthquake killed 320 people and damaged buildings, roads, and airports to the tune of $4 billion.

The Nisqually quake was significantly less violent than two other situations that have occurred before and will occur again: a much more powerful "megaquake" when tectonic plates collide, or a shallow quake on the Seattle Fault.

Unreinforced brick buildings, concrete tilt-up warehouses and office buildings, older multistory concrete structures without adequate steel rebar — and, in the controversial opinion of one prominent engineer, downtown towers built to current standards — could all be demolished by either type of event.

"We assume we know what it's like to go through a huge earthquake because we've been through something like the Nisqually earthquake in the Pacific Northwest.It's a false sense of security,” said Seattle Emergency Management Director Barb Graff.

According to the experts, the Alaskan Way Viaduct might partially or totally collapse, as could several pre-1941 midrise structures and three-quarters of King County's hospital beds, which could be out of action for days or weeks.

Fortunately, public and private owners of landmark structures have implemented seismic modifications as well as repairs to Nisqually quake damage.

For example, the King County Courthouse and the Seattle-Tacoma International Airport control tower have been brought up to code. The state Capitol received a seismic upgrade when its sandstone columns shifted dangerously in 2001.

Prior to Nisqually, a bond issue passed by voters made Harborview Medical Center earthquake-resistant, and area public schools — which mainly spared significant damage because to voter-approved repairs — are continuing to improve.

The Compass Center, Cadillac Hotel, and Seattle Hebrew Academy were among the more severely damaged private properties that were repaired and upgraded.

Progress is slow and steady.

Since the devastating collapse of a double-deck viaduct on the Nimitz Freeway in Oakland, Calif., in 1989, the state Department of Transportation has made sluggish but steady progress in rehabilitating bridges. However, even with the $38 million provided by the 2005 gas tax this biennium, the job will not be completed until around 2070.

The Federal Emergency Management Agency, the Small Business Administration, and the Federal Highway Administration gave $334 million for rebuilding and retrofitting in the first five years after the quake.

Officials are also striving to protect coastal communities from tsunamis, in addition to buildings and roads. Counties are preparing "vertical evacuation" strategies for tsunamis that don't provide enough time for traditional car evacuation with the support of the state and the University of Washington.

Pacific County has devised a plan to construct 13 berms, five towers, and two parking garages where people can ride out a 22-foot-high killer wave despite the lack of financing. Despite the fact that a locally produced tsunami should have a 40-minute warning, the design places facilities in such a way that people may reach them on foot in 15 minutes.

"This is truly cutting-edge technology. This is by far one of the most intriguing projects I've ever worked on "John Schelling, the state's seismic program manager, stated as much.

Engineers have figured a how to reinforce 800 unreinforced brick structures in Pioneer Square, the Central Area, and the University District. Brick buildings accounted for two-thirds of the buildings that were closed, at least temporarily, following the earthquake in 2001.

Money being shook loose

According to 2008 city calculations, bringing them up to code would cost between $25 and $60 per square foot. Unless they're performing a larger refurbishment, that's more than most property owners are willing to pay, according to Seattle planning officials.

Following the quake, Seattle organized committees to look into whether brick owners should be obliged, as many California communities have done, to bring their properties up to modern seismic requirements.

The attempt came to a halt.

Tax incentives, as well as the deployment of police authorities, were discussed.

"We didn't have the money to defer taxes," said committee member Bob Freitag, "and we felt we couldn't put further obligations on property owners when people can't afford electricity for heat."

Seattle and the Port of Seattle have also not erected sea barriers to prevent areas of the Central Waterfront and Harbor Island collapsing into the water during an earthquake.

The city plans to replace the central waterfront sea wall for $300 million, with funds coming from the Army Corps of Engineers, the King County Flood District, and local taxes.

Despite seismically strengthening Terminal 91 for cruise ships, the Port has no mechanism in place to prevent underwater landslides at its container-shipping facilities. Dakota Chamberlain, director of seaport project management, claimed he was unaware of the 2005 Seattle Fault study, which predicted that a slide might shut down the Port for months.

The same report spoke of the possibility of pre-1941 structures of up to 15 stories collapsing, as well as eight-to-40-story buildings built between 1941 and 1974 collapsing. According to the authors, high-rises erected after 1975 "should endure."

However, an op-ed post in The New York Times last year by Peter Yanev, an Orinda, Calif., structural engineer and earthquake consultant, enraged many colleagues by saying that current skyscrapers in Seattle may suffer serious damage or collapse in a megaquake.

"No matter what an expert says, Seattle's structures are not designed for a magnitude 9 earthquake, period." Yes, I expect collapses if we get an earthquake like Chile," Yanev said in an interview. Many of Yanev's engineering colleagues doubt the safety of structures designed around a central core and missing what he believes enough walls or other structural "redundancy."

"We will absolutely not see the collapse of a big high-rise or all of our high-rises in Seattle," said Stacy Bartoletti, president and chief executive officer of Degenkolb Engineers.

"How many of our high-rises will be unusable after an earthquake, and how long will it take to make them usable? is the question on my mind. Instead of focusing on downtown towers, Bartoletti and Pierepiekarz argue that safety initiatives should prioritize an all-too-common hazard: older brick and concrete structures that are prone to life-threatening damage or collapse.

 

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