National Institute for Transportation and Communities

It’s not shocking that bridges built without thought to earthquakes wouldn’t make it through a big quake unharmed. More surprising, however, is how much damage even a relatively small earthquake would cause to Oregon’s bridges.

In an exhaustive OTREC project, researcher Peter Dusicka looked at the most common bridge types in the Oregon highway system. Those bridges weren’t just fragile, he found—they were even more fragile than other researchers and technical guidelines had suggested.

Dusicka published his preliminary findings in a draft report last year. The final report, “Bridge Damage Models for Seismic Risk Assessment of Oregon Highway Network,” is out now. Click here to download.

Most Oregon highway bridges were built before the 1980s, when designers started to consider seismic activity. Dusicka set out to see what would happen to the most common bridge type, continuous concrete multi-beam or girder, during quakes of varying degrees.

To find that out, he had to first know how the ground in the Pacific Northwest moves during and earthquake and second, model how the bridge type would react to these motions. Historical and geological evidence show a catastrophic earthquake will occur sooner or later in the region, Dusicka has said, as the Cascadia subduction zone stores up energy that will be released at some point. (...

Transportation models keep growing more sophisticated. But complicated isn’t necessarily better, Rick Donnelly said during the inaugural seminar in OTREC’s spring 2012 transportation seminar series April 6.

“Better is contextual,” Donnelly said.

Donnelly, who leads the modeling and simulation practice at engineering consultancy Parsons Brinckerhoff, opened the spring seminar series with an introduction to models. Seven more free seminars follow in the series, produced in partnership with the Oregon Modeling Collaborative.

Donnelly detailed questions that model builders and users should ask and offered his thoughts on building more useful and informative models. Click here for a link to the archived presentation.

Although transportation models consider increasingly more information, simpler models can often get the job done with a smaller investment of time and money, Donnelly said. Sometimes the simplest approach actually produces the best results.

“’Better’ is only relevant in the context of what the model is going to be used for,” he said.

The modeling series continues Friday, April 13 with another seminar geared toward non-modelers. The seminar, by Ben Stabler, also of Parsons Brinckerhoff, builds on Donnelly’s opening installment.

Stabler will discuss two approaches to travel modeling and give...

It’s a common occurrence: a digital signboard over the freeway tells you to expect a 15-minute trip, but traffic clears and you arrive in 10 minutes. Or, worse, you hit a clog and arrive in 30 minutes.

Sometimes those signboards, called dynamic message signs, are way off, Portland State University researcher Kristin Tufte found. But sometimes that doesn’t matter.

Tufte examined the signboards, called dynamic message signs, along Portland-area freeways in an OTREC project. Drivers typically reach their destinations earlier or later than the signs told them to expect when a so-called “shock wave” forms or dissipates; that is, when traffic suddenly bunches or clears up.

Currently, only three of the 30 or so message signs in the Portland metro area display travel times. Detectors at freeway onramps feed those signs. As a result, large swaths of freeway without onramps also have no data. To be most useful, new message signs would require more detectors in certain areas.

Take the busy Marquam Bridge in Portland, where busy freeways merge and there is no signboard. “There’s no detection for the whole length of the bridge,” Tufte said. “If you really want to have accurate travel times, you have to have detection there.”

As expected, Tufte found that traffic bunching or clearing in blind zones can throw off the accuracy of travel times displayed. Surprisingly, that inaccurate information is...

Good transportation decisions rely on good models. Yet, despite advances in transportation modeling, there had been no dedicated training ground for the next generation of modelers. That all changed with the launch of the Oregon Modeling Collaborative Nov. 12. The collaborative will serve as a living laboratory to put the research from some of America’s top modelers into practice across Oregon.

On Nov. 12, we welcomed Peter Appel, administrator of the federal Research and Innovative Technology Administration, to Portland to kick off the collaborative with researchers, practitioners and policymakers from across the Northwest. Appel, confirmed by the U.S. Senate as administrator in 2009, has worked on U.S. Department of Transportation initiatives aimed at getting researchers and professionals to address safety, efficiency and environmental sustainability across all forms of transportation.

Groundbreaking research at the Oregon Transportation Research and Education Consortium has already produced models to account for bicycle trips and greenhouse gas emissions and to predict earthquake risk to highway bridges. However, models don’t do any good if agencies can’t afford the staff time and resources to use them. The Oregon Modeling Collaborative helps fill this gap by educating the next...