November 15, 2004

UCSD Shakes 70-Ft.-Tall Wind Turbine In Real-Time
Earthquake Demonstration Of World's First Outdoor Shake Table

By Denine Hagen

A 70-ft.-tall, 23,400-lb. wind turbine shook and shivered while it was subjected to historical ground motions from the 1992 magnitude 7.3 Landers earthquake, as the University of California, San Diego (UCSD) Jacobs School of Engineering today demonstrated the unique capabilities of the world’s first outdoor shake table for testing full-scale buildings and structures.

The test was part of a grand opening for National Science Foundation’s George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES). NSF has invested $81.8 million in the network of large-scale seismic testing laboratories at 15 universities.

“Our demonstration is a first step towards understanding how wind turbines are impacted by earthquakes, a question that will become increasingly important as California becomes more reliant on renewable energy sources such as wind energy,” said José Restrepo, associate professor of structural engineering at the Jacobs School. “A significant concern is the resilience of wind turbines to earthquakes because the main wind energy producing regions of California are within close proximity to active earthquake faults.”

At 25 ft. by 40 ft., the UCSD-NEES Outdoor Shake Table is the largest shake table in the United States. With its powerful hydraulic actuators capable of shaking at speeds up to six ft. per second, researchers are able to reproduce accurate near-fault ground motions, creating realistic simulations of the most devastating earthquakes ever recorded.

“This new outdoor laboratory seals UCSD’s position as the innovation leader in structural testing for earthquake hazard mitigation,” said Frieder Seible, dean of the Jacobs School. “Because there is no roof over the shake table, we are able to use tall cranes and heavy equipment to construct and test full-scale buildings and structures. We can now physically validate many construction systems that have previously been analyzed only through computer models.”

Researchers with the UCSD Department of Structural Engineering will use the shake table to conduct seismic experiments on multi-story buildings, bridge columns and bents, wharfs and piers, and lifeline structures such as electrical sub-stations and satellite towers. The shake table is adjacent to the Soil Foundation-Structure Interaction (SFSI) facility funded by the California Department of Transportation. Taken together, the shake table and SFSI will allow for one-of-a-kind testing of structural systems such as bridge abutments, embankments and foundations.

Construction of the UCSD-NEES Outdoor Shake Table, which is located at UCSD’s Elliott campus at Interstate 15 and Pomerado Rd, was completed in September 2004. The $9 million facility was funded through a $5.9 million grant from the NSF as well as state, university, and private contributions.

The wind turbine along with 5,000 similar machines operated for over 12 years not far from the San Andreas, White Wolf and Garlock faults just outside of Tehachapi, Ca. The turbine was donated by Oak Creek Energy Systems, which is now a member of the Camp Elliott Board of Directors, a group of 44 leading industry associations and Southern California engineering firms, developers and contractors who have committed more than $1 million in support of the new UCSD structural engineering research facility.

Camp Elliott Board Chairman Robert Englekirk said: “UCSD is an innovation leader in developing practical seismic safety construction strategies. The new outdoor shake table will help us increase our understanding of the science of the field, and lead to new ways to reduce seismic risk while at the same time reducing construction costs.”

Camp Elliott Board members include: American Segmental Bridge Institute, Anderson Drilling, Baumann Engineering, Brandow and Johnston Associates, Burkett and Wong Engineers, Carpenters/Contractors Cooperation Committee, Charles Pankow Builders, Ltd., Clark Pacific, Douglas E. Barnhart, Inc., Dywidag-Systems International, USA, Inc. (DSI), Englekirk and Sabol Consulting Structural Engineers, Inc., Englekirk Systems Development, Inc., Enniss Constructors, EsGil Corporation, GEOCON, Inc., Gordon Forward, Highrise Concrete Systems, Inc., Hilti, Hope Engineering, Inc., John A. Martin and Associates, Josephson Werdowatz & Associates, JVI, Inc., KPFF Consulting Engineers, Matt Construction Corporation, Morley Builders, Nabih Youssef and Associates, Occidental Petroleum Corporation, Pacific Southwest Structures, Parsons, PCL Construction Services, Inc., Precast/Prestressed Concrete Manufacturers Association of California (PCMAC), Rudolph and Sletten, Inc., Saiful/Bouquet, Inc., Structural Engineering Association of Southern California (SEAOSC), Simon Wong Engineering, Simpson Manufacturing Company, Smith-Emery Company, Stedman and Dyson Structural Engineers, The Eli & Edythe L. Broad Foundation, Twining Laboratories, UC San Diego Design and Construction, Weidlinger Associates, Inc., Hart-Weidlinger Division, and the Structural Engineering Association of San Diego (SEAOSD).

The UCSD-NEES Outdoor Shake Table is an extension of the Charles Lee Powell Structural Research Laboratories operated by the Jacobs School’s Department of Structural Engineering. The Powell Labs are world-renown for testing large-scale structural systems. Co-investigators involved in the project include UCSD Structural Engineering Professors Joel P. Conte, J. Enrique Luco, José Restrepo, Frieder Seible and Assistant Director for NEES IT operations Lelli Van Den Einde. Larry Berman is the senior development engineer. The general contractor was Taylor Frager and MTS Systems Corporation built the hydraulic system and shake table.

Media Contact: Denine Hagen, (858) 534-2920