Japanese Engineers Visit Oregon

People come from all over for a look at the Oregon Coast’s bridges. On Friday, the visitors hailed from Japan. Their interest, however, was not so much in the arcing grace of the iconic spans, but in two newer bridges most travelers would never give a passing glance.

 

One spans Spencer Creek just north of Newport, the other Millport Slough on Siletz Bay in Lincoln City.

“These are the first two bridges designed with construction for tsunami forces,” said Bruce Johnson bridge engineer for the Oregon Department of Transportation. “They are the only two on the coast that have that. They are the first, as far as we know, in the whole world.”

 

The Bridge Engineering Japanese Consult Group has met with the United States for the past 28 years, alternating each year between the U.S. and Japan. This is the first year the Federal Highway Administration, which organizes the program, asked Oregon to host the meeting, Johnson said.

“They asked Oregon because of the tsunami research,” he said. “We are definitely ahead of Japan.”

The group first visited Portland. On Friday, they convened at the Newport City Hall to hear how coastal communities have prepared for the Cascadia Subduction Zone earthquake, and for a field trip to visit the bridges. That trip included a visit to the Yaquina Bay Bridge.

The Japanese visitors were interested in how the state has worked to preserve the historic bridge from marine salts using cathodic protection, thereby maintaining the its structural integrity. Japan is just getting started on preserving its older bridges, Johnson said.
But while Oregon has kept up on preservation of the 76-year-old bridge, engineers know it won’t fare well in a major earthquake.
“We believe the columns would move back and forth and crack so badly they won’t be able to hold up the bridge,” said Johnson. “I don’t like to use the word collapse but the potential is certainly there.”
Johnson is hoping the state might see the wisdom in starting to put aside money to retrofit Oregon’s bridges and important buildings, rather than wait for them to be destroyed in an earthquake and face replacing them. The cost to replace the Yaquina Bay Bridge would run about $400 to $600 million dollars, while retrofitting would cost in the tens of millions.

 

It’s an idea that will be addressed in the Oregon Resilience Plan, due to be completed by Feb. 28, 2013. The plan came out of a resolution passed by the House of Representatives in 2011, directing state agencies to make recommendations to protect lives and the economy in the event of a major earthquake. Scientists have said there is a 37 percent chance the Cascadia Subduction Zone will rupture in the next 50 years.

 

“Only 20 percent of bridges in Oregon are designed for seismic loads, 80 percent are not and probably would not be usable,” Johnson said. “On the coast, we are predicting none of the cities would have access to another city on the coast. Every city would be isolated.

All state highways would be cut off and there would be no access from the valley to the coast. Five-thousand to 10,000 lives would be lost in the first hour. The problem I have is the 5,000 to 10,000 are just injured and could be saved if you could get to them. We are not going to be able to get them.”
The economy would also be in ruins and without the retrofitting and other preparations, recovery could take as long 10 years, Johnson said.

“The plan will paint a very bleak picture,” said Johnson. It will call for 50 years of investment at $50 million to $100 million a year.

“It sounds like a lot of money, but for that kind of money to save the state from 10 years of economic devastation, it’s a wise decision. If we don’t do something to be resilient, the economy of Oregon is going to be devastated for a long, long time.”

 

oregonlive.com