Installation of Pile. Photo credit: Dr. Amy Cerato
Ram Jack took part in a first-of-its-kind study on seismic behavior of helical piles.
Deep Foundation Institute conducted seismic research at University of California-San Diego—which has the largest shake table in the world used to simulate seismic events. Amy Cerato, Ph.D., P.E., professor at University of Oklahoma, lead the project, “Large-Scale Shake Table Test to Quantify Seismic Response of Helical Piles in Dry Sand.”
Weights for free head condition Designed by Ram Jack Engineering. Photo credit: Dr. Amy Cerato
While helical piles are widely used in seismic areas in Japan and New Zealand, very little data about seismic behavior on helical piles in the U.S. is available. Testing of this nature is necessary to better understand the role of deep foundations, specifically steel piles, in highly active seismic zones in the United States.
All future studies on seismic effect on helical piles will reference this study.
Dr. Cerato writes on her project blog , “This project will benefit people living in seismic zones by educating engineers with full-scale helical pile experimental data so that they better understand how to design a building system that is safer, more resilient and sustainable for individuals and the community.”
Ram Jack’s Role in Testing
Ram Jack Helical Piles. Photo credit: Dr. Amy Cerato
Ram Jack provided cash, engineering assistance, fabrication (specialty pile caps and free head condition weights), (4) 3 ½” diameter helical piles with single and twin helical plates and a 3 ½” diameter driven pile.
Test Pile Information
- All piles consisted of a 7 ft. lead and 5 ft. extension.
- Both single and double helix plate configurations were used.
- Piles were installed in sand.
- Installation torque for 3 ½” dia. piles: 7.5 to 10 ft-kips
- Installation torque for 5 ½” dia. piles: 24 to 27 ft-kips
The seismic force of the test was to model seismic events that have occurred:
- 1994 Northridge, CA (6.7 magnitude)
- 1995 Kobe Takatori, Japan (8.9 magnitude)
UCSD Helical Pile Seismic Test - Video
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