Testing at Cornell’s Large-scale Geotechnical Lifelines Facility can be a major undertaking especially when our large-scale test basin is involved. Watch this greatly sped up time lapsed video of the effort required for a typical research project.
Author: Joseph Chipalowsky
NYSEARCH has recently completed some important testing on the longevity and extreme capabilities of cured-in-place lined pipe. Their tests used lined pipe that was extracted after more than (10) years in live pressurized gas service and then tested to extremes by experts at Cornell University.
A top engineer from the city of Los Angeles visited Cornell July 20-22 as researchers tested a new earthquake-resilient pipeline designed to better protect southern California’s water utility network from natural disasters.
The steel pipe, developed by JFE Holdings in Japan, uses a unique structural wave design to control buckling, allowing the pipe to bend and compress without rupturing or losing water pressure. The wave features are installed at key locations along the pipeline to absorb large ground deformation, such as movements imposed by earthquakes and landslides or from undermining associated with scour during hurricanes and floods. The extent of its performance was unknown until it arrived at Cornell.
“It surpassed expectations,” said Tom O’Rourke, professor of civil and environmental engineering and the project’s principal investigator. O’Rourke is a member of a research team with Harry Stewart, director of the Cornell Geotechnical Lifelines Large-Scale Testing Facility; lab manager Tim Bond; and other lab personnel, including graduate and undergraduate students. They ran multiple tests, including an earthquake simulation in which a 28-foot-long section of the pipe was outfitted with more than 120 monitoring instruments and buried within 80 tons of soil – an experiment that took over a month for the research team to prepare.
The test mimicked a fault rupture that can occur during an earthquake when global plates begin to slip past each other, causing the ground to shift and deform. A large, hydraulically powered “split box” imposed 2 feet of fault rupture along a 50-degree angle, forcing the buried pipeline into a combination of compression and bending.
“The pipe was able to accommodate the 2 feet and didn’t spring a leak,” said Brad Wham, a geotechnical engineering postdoc who designed the test. “We took the pipe to three times its current design standard, and it continued to convey water. So we consider it a successful test and very promising technology.” And while the test pipe was only 8 inches in diameter, Wham says the results are scalable and could be applied to pipelines as large as 70 inches in diameter or greater.
The results are significant for Los Angeles and other West Coast cities that want to upgrade their aging utility systems, especially portions that cross over fault lines. Craig Davis, the resilience program manager for L.A.’s Department of Water and Power, attended the Cornell testing and said his city’s water utility system – the nation’s largest – crosses over 30 fault lines en route to supplying water to more than 4 million residents. The new pipe produced by JFE Holdings now gives Davis and other engineers a new option for securing water supply to the city’s most vulnerable areas.
Los Angeles is upgrading its water utility system through the “Resilience By Design” program implemented by Mayor Eric Garcetti, and other municipalities around the country are eager to initiate similar programs following natural disasters like Hurricane Katrina and Superstorm Sandy.
“What we’ve actually seen is a paradigm shift in pipeline technology, and it’s a market-driven research environment,” said O’Rourke, who added that a steady stream of business from manufacturing companies like JFE Holdings has kept his facility in high demand. “All of the West Coast utilities say that if you want us to consider your pipe, you have to test it Cornell. Ours is the only facility in the world that can perform these kinds of tests.”
Following the fault rupture test, Stewart, Bond, Wham, O’Rourke and the team of undergraduate and graduate students spent three days carefully excavating the pipeline and will begin collecting additional data based on its deformation. The results will help officials identify the most strategic locations for the new pipeline to be installed. “We modeled the Los Angeles water supply and have the entire system on a secure computer,” said O’Rourke. “We created the next generation of hazard-resilient network modeling, and they actually used it to develop policy and emergency response operations.”
Los Angeles is not the only city to benefit from Cornell’s unique testing facility. San Francisco has implemented fault rupture hazard solutions for pipelines validated by Cornell, with Portland, Seattle and Vancouver all considering upgrades based on recent test results.
A length of pipe is buried in the hydraulically powered “split box,” which forces the pipe into a combination of compression and bending. Following the test, the pipe is excavated and data on the deformation is collected.
Robert Barker/University Photography
Syl Kacapyr is public relations and content manager for the College of Engineering.
For more than 50 years, the Karl Terzaghi Lecture has been given by an individual honored for their exemplary contributions to the field of geotechnical engineering. The 2016 Terzaghi Lecture was presented on Tuesday, February 16 at the Geotechnical & Structural Engineering Congress by Thomas D. O’Rourke, Ph.D., Hon.D.GE, NAE, FREng, Dist.M.ASCE. Dr. O’Rourke is the Thomas R. Briggs Professor in Engineering at Cornell University.
There are millions of km of pipelines in the U.S., and tens of millions worldwide used in water supplies, gas and liquid fuel delivery systems, electric power networks, and wastewater conveyance facilities. Geotechnical and structural engineers play a critical role in managing the performance of these systems that are affected by ground deformation arising from tunneling, deep excavations, and subsidence due to dewatering and mineral extraction as well as geohazards, such as earthquakes, floods, and hurricanes.
The lecture explores the mathematical functions used to characterize soil deformation in response to underground construction and natural hazards. It examines both the soil and structural mechanics of soil-pipe interaction under various ground movement patterns, including the material and geometric nonlinearities of pipelines, conduits, and soil. Guidance is provided for estimating tolerable levels of ground deformation for frequently encountered continuous and segmental pipelines subject to tunneling, open-cut excavation, and extreme events, such as earthquakes and landslides. Large-scale laboratory testing and numerical modeling for the next generation hazard-resilient pipelines are described, and innovative ways of accommodating ground deformation are illustrated. Water supply and wastewater system response to widespread liquefaction-induced ground deformation during the Canterbury earthquake sequence in New Zealand are evaluated with high density LiDAR and GIS analyses.
Dr. O’Rourke is an expert on natural disasters and their impact on the infrastructure supporting civil society, pipelines, and underground construction. He authored or co-authored over 360 publications on various geotechnical topics. He served on several teams reviewing and reporting on significant disasters such as Hurricane Katrina and earthquakes around the world. O’Rourke also headed a team that analyzed the impact on infrastructure systems of the attack against New York City on September 11, 2001. He served as chair or member of the consulting boards and peer review of many large infrastructure projects. Throughout his career, Dr. O’Rourke received many honors, including ASCE’s Stephen D. Bechtel Pipeline Engineering, Ralph B. Peck, C. Martin Duke, and LeVal Lund Awards. He is a member of the National Academy of Engineering and International Fellow of the Royal Academy of Engineering.
ASCE, the American Society of Civil Engineers recently presented an Outstanding Civil Engineering Achievement Award (OCEA) for the seismic upgrade of Bay Division Pipelines Nos. 3 and 4 at Hayward Fault in Fremont, CA. The story and a video can be found on line in the March 2016 issue of ASCE News.
The design concept tests for this project were performed at the Cornell Large – scale Lifelines Testing Facility.
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