Testing Earthquake-Proof Water Pipelines

Shaken, but not stirred is the objective of a newly developed pipeline solution to be implemented in Los Angeles. This steel pipe utilizes a structural wave design which controls buckling. The pipe can bend and compress without rupturing or experiencing a pressure drop in the water.

Earthquakes, landslides and other geological instabilities, as well as issues due to scour from hurricanes and floods are all absorbed by the pipeline using the wave features installed at specific locations across the pipeline.

Testing Pipeline Strength

The pipeline was tested at the Cornell Geotechnical Lifelines Large-Scale Testing Facility. Performance of a 28-foot-long pipe was evaluated using an earthquake simulation, with over 120 monitoring instruments within 80 tons of soil.

The pipe was subjected to a large, hydraulically-powered “slip box” which created 2 feet of fault rupture at a 50-degree angle. This placed the pipeline under conditions of both compression and bending. The test was considered passed when the pipe was subjected to three times its design standard and it did not stop transporting water. According to Brad Wham, a geotechnical engineering postdoc, “The pipe was able to accommodate the 2 feet and didn’t spring a leak.” Wham was responsible for designing the test.

(Image courtesy of Cornell University.)

Upon the completion of the test, the engineering research team took three days to excavate the pipeline. Once recovered, they will proceed to collect more data using its resulting deformation. This information will make it possible to choose the most strategic locations for the new pipeline.

Pipelines on Fault Lines

For Los Angeles, and other regions crossing over fault lines, this is a very attractive technology. L.A.’s water utility system crosses over 30 fault lines on the path to supplying over 4 million residents with water.

(Image courtesy of Cornell University.)

However, L.A. is not alone in benefitting from Cornell’s test space. San Francisco has already implemented pipeline solutions validated by the Cornell facility. Furthermore, Portland, Seattle, and Vancouver are all considering upgrades following this most recent round of testing.

The pipeline technology tested by Cornell for use by L.A.’s Department of Water and Power was developed by Japan-based JFE Holdings.

For more reading on pipeline testing, check out this article on pneumatic tests versus hydrostatic tests.