A new form of wave-shaped steel piping promises to enhance the seismic resistance of oil or water utilities infrastructure that traverses earthquake-prone fault lines.
The steel pipe developed by Japan's JFE Holdings employs an innovative structural design to reduce buckling during the imposition of heavy stress at the vulnerable points of infrastructure lines.
The pipe's wave-shaped design enables it to bend and compress when subjected to heavy force, as opposed to bursting or rupturing completely. This ability should enhance its resistance to the various forms of stress created by natural contingencies, such as ground deformation following earthquakes and landslides or the undermining produced by scour during hurricanes and floods.
Engineers at Cornell University have used their own unique testing facilities to demonstrate that the wave-shaped pipe is indeed capable of withstanding intense seismic events.
The testing experiment saw Cornell engineers bury a 28-foot-long section of the pipe in 80 tons of soil, and equip it with 120 monitoring devices.
The engineers then simulated an earthquake by means of a hydraulically powered "split box," creating two feet of fault rupture along a 50-degree angle that subjected the buried pipe to simultaneous compression and bending.
According to Brad Wham, the geotechnical engineering postdoc from Cornell who was responsible for devising the test, the pipe managed to withstand seismic rigours well in excess of its design requirements.
"The pipe was able to accommodate the 2 feet and didn't spring a leak a leak," said Wham. "We took the pipe to three times its current design standard, and it continued to convey water.
"We consider it a successful test and very promising technology."
"It surpassed expectations," said Tom O'Rourke, professor of civil and environmental engineering at Cornell University and principal investigator for the project.
According to O'Rourke, efforts by Los Angeles and other municipalities in California to upgrade their ageing water utilities infrastructure have spurred the use of Cornell's unique scientific facilities to test the latest pipeline technology.
"What we've actually seen is a paradigm shift in pipeline technology, and it's a market-driven research environment," said O'Rourke. "All of the West Coast utilities say that if you want us to consider your pipe, you have to test it at Cornell."
The successful test results for the JRE Holdings pipe paves the way for its use as a replacement option for vulnerable water infrastructure in California that traverses multiple seismic fault lines.