An OTREC research project recently took a look at gusset plate connections, the riveted plates of sheet metal that hold steel truss bridges together.

These connective plates have come to the attention of the Federal Highway Administration (FHWA), because in 2007 the collapse of the Interstate-35W Bridge in Minneapolis was the result of a failed gusset plate.

After the collapse, which killed 13 people and injured 145, the FHWA issued a set of guidelines for load rating — or determining the weight-bearing capacity — of gusset plates.

Historically, only bridge truss members were considered for load rating during safety inspections. Gusset plates were thought to be reliable based on conservative assumptions employed during their design.

For more details, visit the project page.

Roughly 20,000 steel bridges in the United States are classified as non-load-path-redundant, or fracture critical, bridges. This means that the failure of a single truss member or connection could lead to collapse.

The problem, says the project's lead investigator Christopher Higgins, happens when a plate goes out of plane. It’s supposed to be perfectly flat, but with too much load put on it, it can develop a bifurcation and go from stable to unstable.

“It’s like stepping...

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During Hurricanes Ivan in 2004 and Katrina in 2005, at least 11 highway and railroad bridges along the U.S. Gulf Coast were damaged. When the water rose during the storms, wave forces slammed into the bridges’ supporting substructures, and when it rose high enough, the water’s buoyancy had enough power to lift off sections of a bridge’s superstructure and lay them aside like giant Legos.

To build bridges that can withstand the force of hurricane waves, engineers must be able to estimate the effects those waves will have on bridge structures. An OTREC project led by Oregon State University professor Daniel Cox examined the effects of wave loading on highway bridge superstructures.

Cox and co-investigator Solomon C. Yim, also of Oregon State University, conducted experiments in the Large Wave Flume at the O.H. Hinsdale Wave Research Laboratory at Oregon State University. They used a 1:5 scale, reinforced concrete model of a section of the Interstate 10 Bridge over Escambia Bay, Fla, which failed during Hurricane Ivan.

To see more details about the project, “Hurricane Wave Forces on Highway Bridge Superstructure,” click here, or download the final report.

The problem addressed by this...

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Oregon Institute of Technology students got an up-close look at bridge engineering on a large scale during a trip to the Mount Shasta area Sept. 28. A group of 16 students and faculty members Roger Lindgren and Matthew Sleep from the civil engineering department visited the Antlers Bridge Replacement construction site. The trip was organized by Oregon Tech’s Institute of Transportation Engineers student chapter with funding provided by OTREC.

Eric Akana, P.E., of the California Department of Transportation hosted the tour with CalTrans engineers Shari Re, Bill Barnes, and Mark Darnall.

The new Antlers Bridge, which spans the Sacramento River arm of Lake Shasta near the town of Lakehead, California, will be a balanced cantilever cast-in-place concrete bridge. The new bridge will consist of five spans coming together to make a 1,942-foot structure, approximately 600 feet longer than the original Antlers Bridge. The new bridge will replace an aging steel structure that is reaching the end of its service life. In addition, a section of highway south of the bridge will be realigned because of a high accident rate.

The Oregon Tech group met with CalTrans engineers for an extensive project review presentation at the field office and then proceeded to the construction site where they spent over two hours viewing foundation preparation, pier construction, pier-table form travelers, and abutment work.

In addition to viewing construction details and...

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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. (...

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A major seismic event is predicted to hit the Oregon Coast any year now, which has transportation planning experts asking, “Is Oregon prepared?”

OTREC seismic expert and Portland State University Associate Professor of Civil and Environmental Engineering Peter Dusicka recently spoke at a May 13 symposium titled, Next Big Earthquake In Oregon: Are We Ready? Along with five other PSU professors, the Maseeh College-sponsored symposium addressed the state’s preparedness in terms of emergency response and infrastructure. Dusicka’s talk focused on the ability of Oregon’s bridges to perform in a major earthquake.

“We depend on our network of bridges for anything from immediate emergency response to transportation of goods and services,” Dusicka said. “There is no doubt that there is an inventory (of bridges) within Oregon of a certain vintage where we know there will be issues.”

The ability of a bridge to withstand a seismic event can depend on the type of bridge, when it was constructed and how it’s supported in terms of a foundation, Dusicka said. OTREC recently worked with ODOT to examine several hundred bridges in Oregon for seismic deficiency. The most telling trait, Dusicka said, is age.

“Over time, we’ve learned the ways we’ve designed and built bridges are not the best for resisting earthquakes,” Dusicka said. “The challenge with remediation today is, do we have the knowledge to do this effectively, and if we do, do we have the funds to execute...

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As a student at the University of British Columbia, Peter Dusicka pursued earthquake engineering in part because so few others had taken that path. “I was looking for a way to make a difference and looking for areas within civil engineering that seemed immature,” Dusicka said.

There was too much guesswork as to how well the Pacific Northwest’s transportation network would handle the type of subduction zone earthquakes the region is prone to. Now, thanks in part to Dusicka’s research, we know a lot more.

When it comes to the fragility of Oregon’s transportation system, the recent earthquakes around the Pacific Rim provide more insight into a major quake than do models developed for North America, said Dusicka an OTREC researcher and Portland State University associate professor. “The subduction zone earthquake in Oregon, Washington and British Columbia isn’t a threat anywhere else in the U.S.,” he said.

The recent Japanese quake as well as the one in Chile—both subduction-zone quakes—are more instructive. Subduction-zone quakes tend to be larger magnitude, shake longer and affect a larger geographic area than other earthquakes.

The serious earthquake related damage in Japan probably would have been worse had that country’s leaders not been spurred by the 1995 Kobe earthquake. “The Japanese people and...

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designBridge is a student-based organization at the University of Oregon that exposes students to real architectural and planning projects in their community. The organization promotes studentsí engagement in their community while providing them with professional experience that will benefit them in their careers. In this OTREC-funded education project, led by Professor Nico Larco, the students of designBridge undertook the design and construction of a new transportation shelter for Roosevelt Middle School in Eugene, Oregon. The project results include not only the completion of the shelter but also the continued development of a service learning program that can effectively address small community transportation-related needs. To learn more about the project, down the final report at: https://ppms.trec.pdx.edu/docs/detail/2172

The Sustainable Endowments Institute has chosen to honor the University of Oregon’s OTREC supported designBridge program as a Champion of Sustainability in Communities. UO’s designBridge program, a student-run organization that offers environmentally friendly, community-based design-build services to the local area, was named as one of four honorable mentions. designBridge utilizes resources from the UO School of Architecture and Allied Arts, other campus departments and Eugene/Springfield community businesses to work on a variety of service projects, including a seedling greenhouse for Northwest Youth Corps and a bike shelter for Edison Elementary School in Eugene. Assistant Professor of Architecture Nico Larco currently supervises students Drew Hastings (project manager), Nick Wallace, Kent Wu, Truc Bui and Vito Cerelli on the project. Last fall students Patrick Hannah (project manager), J. Ho Lee, Kelley Stewart, Lucas Gray and Paul McBride worked on the designBridge project.

Dr. Larco (left) is pictured standing in a renewed and re-invigorated bicycle parking area at Edison Elementary school in Eugene. designBridge worked with kids, parents, and school administrators to completely re-design this area over the course of the last year. So far this year, bike ridership has doubled and the kids and parents are loving the design work that Nico’s students have done.

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See the PSU Vanguard's coverage and video interviews on this seminar.

In the last decade, three important new bridges in the Portland area were the subject of intense discussion and analysis: the Tilikum Crossing, the Sellwood Bridge and the Columbia River Crossing. One of those bridges is completed, the second is under construction and the third one was canceled.

As a Metro Councilor, Robert Liberty was involved in the decision making process for all three projects. The way in which those projects were analyzed and presented to the public revealed to him a great deal about the many weaknesses in the way we make major transportation investment decisions. Those insights are the topic of his seminar presentation.

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Cities and Bridges: A World History

Daniel Biau, international consultant, civil engineer and author of The Bridge and the City: A Universal Love Story, will share insights on urbanization and bridges.

Across countries and centuries, the session will explore a fundamental social and demographic change: the emergence of a planet of towns and cities. But it will look at this densification of human and economic relations through a specific lens, the increased connectivity triggered by strategic urban bridges. 

As places of encounters and exchanges, bridges have played a major role...

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