UCLA's earthquake center will receive $4.5 million of a $105 million grant given by the National Science Foundation to Purdue University to spearhead a national earthquake simulation network.
Purdue will serve as headquarters for the operations of the George E. Brown Jr. Network for Earthquake Engineering Simulation (NEES), created by the NSF in 2000 to give researchers around the country the tools to learn how earthquakes and tsunamis impact critical infrastructure, including buildings, bridges and utility systems. The NSF grant spans five years.
NEES@UCLA, the campus's large-scale earthquake experimental resource site, will continue to serve as one of the network's 14 sites, which feature advanced simulation tools such as shake tables, centrifuges, a tsunami wave basin, unique laboratories and other equipment. The UCLA site specializes in the field testing and monitoring of geotechnical and structural performance, and the site's state-of-the-art mobile field laboratory will allow researchers to glean significant new insights based on the response of full-scale test specimens under realistic field conditions.
"We offer unique field-testing capabilities for full-scale earthquake engineering testing," said Robert Nigbor, co-principal investigator of NEES@UCLA. "We can shake and even break big structures with our vibration equipment."
According to the NSF, more than 75 million Americans in 39 states live in towns and cities at risk for earthquake devastation. In the past decade, according to the U.S. Geological Survey, 124 major earthquakes — those with moment magnitudes exceeding 7 (similar to the Richter scale measurement) — have occurred throughout the world.
All NEES experimental sites are linked to a centralized data pool and earthquake simulation software. Collaborative tools and telepresence technologies allow off-site researchers throughout the U.S. and around the world to interact in real time with any of the networked sites.
"Prior to NEES, we simply did not have national facilities," said Jonathan Stewart, professor of civil and environmental engineering at UCLA's Henry Samueli School of Engineering and Applied Science and a co-principal investigator of NEES@UCLA. "We could not run the type of experiments we run now. Today, there is a lot more high-quality experimental work being done. There's been a shift in culture as well. Resources and information are shared freely among the community, and that wasn't always the case. We see NEES@UCLA as a resource to the entire country."
Since its establishment, NEES@UCLA has worked with several other institutions, including UC San Diego, Brigham Young University, Rice University, the University of Texas at Austin and the Carnegie Institute of Washington, and has had several service-to-industry projects with the California Department of Transportation, the U.S. Geological Survey, the Jet Propulsion Lab and Los Angeles World Airports. NEES@UCLA averages about five active projects per year.
Current Research at NEES@UCLA
Stewart is currently working on two large-scale research projects for NEES as well. One, the NEES Grand Challenge Project, aims to develop effective strategies for identifying older, seismically hazardous non-ductile concrete buildings in Los Angeles — a project that could lead to the creation of lifesaving public policy.
Twenty years ago, the buildings with the greatest potential risk of collapse were unreinforced masonry buildings or brick buildings with no reinforcing bars. Today, due to state ordinances, virtually all unreinforced masonry buildings have been removed or retrofitted. The next hazard on the list, according to Stewart, is non-ductile concrete buildings.
"Non-ductile means if you start deforming it, like a piece of uncooked spaghetti, it can snap," said Stewart, who is co-principal investigator on the project. UC Berkeley's Jack Moehle serves as principal investigator.
The California Governor's Office of Emergency Services estimates that more than 40,000 non-ductile concrete buildings exist in the state. But observations made following major earthquakes suggest that only about 5 to 15 percent of these buildings collapse.
"So how do we distinguish the really hazardous ones from the larger pool? This is a critical problem for many seismically active regions around the world, and accordingly, this is a high-profile, critical project, involving investigators from all over the U.S.," Stewart said. "The project has been organized with L.A. serving as our test bed."
The second major project involves an analysis of the seismic vulnerability of levees along the Sacramento–San Joaquin Delta. These levees are critical components of California's water distribution system. The delta supplies fresh water to 22 million people in Southern and Central California, as well as eastern portions of the Bay Area.
Within the delta are islands surrounded by the levee system. Though the ground level of the islands is below the water level, water is not able to flow in because of the levees.
"So you can imagine, you've got these rivers flowing through this system of levees surrounding very low-level islands, many of which are farms. What happens if there is a failure in one of the levees? Water flows right in and fills up the island like a big bathtub," said Stewart, who is working on the project with principal investigator Scott Brandenberg, UCLA assistant professor of civil and environmental engineering.
"These are big islands. A lot of fresh water is lost and a lot of money is spent fixing the problem," Stewart said. "But the biggest concern is when an earthquake causes simultaneous levee failures at multiple locations. It would be beyond the ability of the state to fix the problem. This would lead to seawater intrusion to the intake facilities for the California Water Project, compromising water delivery for more than 22 million Californians."
A recent bond measure has directed significant resources to levee retrofitting projects. Unfortunately, engineers lack the tools to assess seismic risk for one of the most common levee configurations — earthen levees overlying soft organic peat soils — and do not understand the potential seismic failure mechanisms associated with such levees
Brandenberg and Stewart team plan to build their own levee and shake it with the NEES@UCLA equipment to see whether it undergoes a seismic failure, and if so, by what deformation mechanism. Lessons learned from this work will help advise the ongoing levee risk-assessment and retrofit efforts.
The UCLA Henry Samueli School of Engineering and Applied Science, established in 1945, offers 28 academic and professional degree programs, including an interdepartmental graduate degree program in biomedical engineering. Ranked among the top 10 engineering schools at public universities nationwide, the school is home to five multimillion-dollar interdisciplinary research centers in wireless sensor systems, nanotechnology, nanomanufacturing and nanoelectronics, all funded by federal and private agencies.
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