PROTECTING CRITICAL ENERGY INFRASTRUCTURE
Wang was also instrumental in bringing attention to seismic vulnerability at the Critical Energy Infrastructure Hub, a six-mile stretch of the Willamette River that’s home to much of the state’s infrastructure for energy production. The area includes transmission lines, natural gas facilities and more than 600 large fuel tanks — holding roughly 90% of the fuel entering the state.
This infrastructure hub would be extremely vulnerable to damage during an earthquake. The facilities are on liquefiable soils: in response to long and intense shaking, the ground could become like quicksand — collapsing in on itself and shifting toward the river.
“Some people call it Oregon’s future Fukushima,” says Arash Khosravifar, associate professor in Civil and Environmental Engineering, referring to a seismically induced 2011 nuclear disaster at a power plant in Japan. “It’s one of the largest threats we face in Oregon.”
Not only do the fuel tanks sit on liquefiable soils, the tanks themselves are vulnerable to cracking or breaking if subjected to intense vibrations. Traditional methods of ground improvement that prevent liquefaction involve drilling, and risk damage to the tanks.
In response to the need for a low-impact method of ground improvement at the infrastructure hub, Khosravifar, along with Diane Moug, assistant professor, and Kayla Sorenson, Ph.D. candidate, are testing a soil-improvement technique called “microbial induced desaturation.” Their work is funded in part by a grant from the National Science Foundation.
Microbial-induced desaturation works by pumping nutrients into the soil to feed bacteria in the ground. When the bacteria eat the nutrients, they essentially burp nitrogen and carbon dioxide gas. This increases the amount of air in the soil and decreases the amount of water.
“The gas bubbles act like an airbag in a car,” Khosravifar says. “They absorb the energy when the earthquake hits the ground, and that’s how it mitigates liquefaction.”
In 2019, PSU researchers and their collaborators from Arizona State University and the University of Texas at Austin became the first researchers in the U.S. to test this technique in the field at two sites in Portland. Sorenson continues to monitor one of the sites to understand how long the mitigation effect lasts.
“If this method works, it could be really groundbreaking,” Khosravifar says.
BRIDGING A MORE RESILIENT FUTURE
As PSU researchers look to the future of earthquake preparedness, they are also thinking about novel methods to make rebuilding after an earthquake easier and more efficient
“When I first started, we were focused on ensuring infrastructure doesn’t collapse and kill people,” Peter Dusicka, department chair and professor, says. “Now we’re thinking about performance beyond life safety so, after a disaster, people can return to these buildings more quickly.”
Dusicka, who has worked at PSU for two decades, says Rad’s work is part of what brought him here. Now, Dusicka runs the iSTAR lab that Rad helped start. iSTAR’s shake table — the largest in the Pacific Northwest — simulates the shaking of an earthquake. Researchers use it to test how earthquakes impact infrastructure.
“Rad helped put PSU on the map for earthquake research,” Dusicka says. “He was instrumental in getting the lab to where it is today and bringing the shake table into the lab, all of which helped bring faculty like Khosravifar, Moug and myself, and the projects we’re working on today.”
Much of Dusicka’s current research focuses on structural systems and new technologies that can ride out an earthquake with minimal damage.
One example is his work on vulnerable bridges in the Pacific Northwest. Dusicka and his team looked to retrofit these bridges with a metal fuse, or bracket, that helps concentrate damage within a replaceable component. This way, the bridge not only survives an earthquake: in theory, the repair after an earthquake would be as simple as replacing the bracket.
In 2020, the metal fuse was installed on two Interstate 5 bridges in southern Oregon. But before that, the team tested the concept in the iSTAR lab.
To do this, Dusicka and his team reconstructed the columns and beams that support the bridge and installed the test bracket to the structure. Then, they shook the structure to mimic a high-intensity earthquake like “The Big One.”
“The fuse performed very well in the lab,” Dusicka says, adding that the experiments allowed them to test brackets with different features and identify the ones with optimal performance. “These lab experiments were crucial at validating the concepts,” he says.
Moving a concept from the lab to implementation is no small feat. “In the field of civil engineering, it is really hard to implement new technology because of the potential impact on society,” Dusicka says. But a combination of regional need, leadership at the state level and PSU’s expertise has paved the way for implementation across several different projects.
Having worked both for the State and at PSU for many years, Wang has seen this firsthand. “You want as many people as possible to buy in, and to help, and to be engaged to be part of the solution,” Wang says of earthquake preparedness. “PSU has been a leader in that.”