Landslides are often caused by fire; earthquakes often cause fire by rupturing gas and electrical lines. Broken mains and other distribution components severely hamper a fire department's efforts and cut off drinking water supplies; and cities in particularly active seismic zones have taken great pains to ensure neither happens. San Francisco, for example, developed a one-of-a-kind pipeline design.
Now, testing by Cornell University’s School of Civil and Environmental Engineering shows that an American Cast Iron Pipe Co. joint system withstands at least 21.5 inches of axial extension. That's enough to resist more than 99% of ground strains measured after the Canterbury Earthquake Sequence in Christchurch, New Zealand, which exceeded levels generated by California's Loma Preita and Northridge earthquakes.
“For the more than 50% of communities in areas at risk of seismic activity, choosing an earthquake-resistant system will go a long way toward saving lives and minimizing property damage,” says Derek Scott, marketing and technical manager with American Flow Control, American Cast Iron Pipe Co.'s valve and hydrant division.
Read the test results of American's earthquake joint system, which was introduced in 2015 for use with ductile iron pipe, valves, and hydrants, at https://lifelines.cee.cornell.edu/files/2017/05/American-Earthquake-Joint-System-for-Resistance-to-Earthquake-Induced-Ground-Deformation-2ibjh0p.pdf.
"The Geotechnical Lifelines Large-Scale Testing Facility specializes in full-scale tests of pipeline materials and performance in response to seismic activity, is the only one of its kind,” says David Drake, American’s technical director. “Making the grade here was important in validating the design of our product.”
This fast motion video taken during the Cornell study shows the ground’s surface under a simulated earthquake with the joint system buried underneath. A second video shows the test crew unearthing the joint afterward.