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UC San Diego: Denine Hagen
(858) 534-2920,

California Department of Transportation:
Steve Saville, (619) 688-6678

Editors note: A high resolution image is available for download.

$15 million Earthquake Testing Facility at UC San Diego to Evaluate New Technologies to Retrofit California Bridges

August 16, 1999 (San Diego, Calif.) UC San Diego and the California Department of Transportation (Caltrans) today officially opened the new Caltrans Seismic Response Modification Device Testing Facility at the UC San Diego campus. The facility is the first in the world of its kind and scale, and is designed to test new technologies to retrofit the state’s longest span bridges.

Equipped to provide a realistic three-dimensional earthquake simulation, the facility’s testing table is 16 feet-long by 12 feet-wide, and can move horizontally in all directions, lift and lower, rotate, and shake at velocities of up to 70 inches per second.

Long-span bridges including the western approach to the Oakland-Bay Bridge, the San Diego-Coronado Bridge and the Benicia-Martinez Bridge are among those targeted to be retrofitted for earthquake safety through the Caltrans Toll Bridge Retrofit Program. Rather than strengthening hundreds of thousands of individual components of the bridges, Caltrans is exploring the use of huge isolation bearings and dampers, which would be placed between the bridge superstructure and the supporting piers. These devices would absorb the shock of the earthquake and allow large displacements (movement confined to the bearings) to prevent collapse and damage to the bridges.

“California is leading the world in developing and using new technologies to save lives and keep our highway bridges safe during major earthquakes,” said Caltrans Director Jose Medina. “This new testing facility will allow us to tap the best bridge engineering minds from government, academia, and the private sector on an on-going basis as we expand our knowledge and understanding of the science of earthquake engineering.”

The new facility will be used to verify these very large bearings (up to 12 feet in diameter) and dampers which have never been built, tested or used before. The system is powered by computer-controlled hydraulic actuators connected to the testing table. Vertical actuators can apply up to 12 million pound loads (similar to the weight of a long-span bridge) on top of bearings and dampers during earthquake simulations. The facility also includes a reaction wall and a removable steel cross-beam, thus making the system flexible to perform in many different testing setups.

“We are placing the safety of the bridge on the function of a these special devices,” said Frieder Seible, chair of structural engineering at UC San Diego’s Irwin and Joan Jacobs School of Engineering and director of the facility. “We must be sure that the devices will work as designed and that is why this facility is so critical.”

Smaller isolation bearings and dampers have been used to retrofit buildings and bridges in the past. But such devices are not strong nor large enough to support the state’s longest toll bridges. Under the Caltrans contract, UC San Diego will verify all manufacturers’ devices before the devices are approved for use in bridges, and UC San Diego will test these devices at five-year intervals. The facility will also be available to industry and academic researchers worldwide.

If the bearing and damper technology proves successful, Caltrans will begin using it to retrofit the Benicia-Martinez Bridge as early as next year.

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