Successful Demonstration of New Isolated Bridge System at UCB Shaking Table

On May 26, 2010 over 100 engineers, researchers, media representatives and members of the public were on hand to witness the demonstration of a new isolated bridge system at the PEER Earthquake Simulator Laboratory at UC Berkeley’s Richmond Field Station. The bridge was subjected to various ground motion records and varying intensity levels including the 1985 Liollio Chile record, the 1995 Kobe Japan JMA record, the 1978 Tobas Iran record and the 1994 Sylmar Northridge record, The bridge performed as expected without damage and the train that had been placed on the bridge deck was still fully operational after the earthquake and was able to slide easily on its rails. Photo Gallery.

In this new bridge system, all three bridge segments are supported using seismic isolators and utilize the new Segmental Displacement Control Isolation System, which was being tested for the first time. In this approach, the movement of the three isolated bridge segments is constrained so that the bridge’s road centerline remains continuous without residual offsets thus improving driver safety, minimizing the need to realign the different segments following and earthquake, and minimizing damage to the joints provided between segments along the bridge. This is achieved using special lockup guides between the bridge segments, triple pendulum isolators above the bridge column bents, and linear isolation bearings at the ends of the bridge.

Because of the ability of the Segmental Displacement Control Isolation concept to keep the bridge segments aligned during earthquakes, this technology may be particularly attractive for use in protecting high speed rail systems being constructed in California and around the world. Stephen Mahin, PEER Director and UC Berkeley professor of Civil and Environmental Engineering, and Ken Orgozalek, UC Berkeley gradate student in Civil and Environmental Engineering, are conducting this research.

The test was a completed as a part of PEER’s Transportation Research Program, which has been conducting research on various new bridge designs that are able to withstand large earthquakes without significant damage. By eliminating the need for extensive bridge repair, closure, or replacement after earthquakes, these new designs can prevent disruption of emergency response and recovery efforts, thus making our communities more resilient. Emphasis is placed on bridge systems that can be constructed more quickly and economically, and with less impact on the environment. Some new design approaches include systems that use new low carbon materials, rock on their foundations, deform but automatically re-center following a major earthquake, or are prefabricated to promote high quality and rapid construction.

EPS

This research was funded by PEER, the National Science Foundation and Earthquake Protection Systems, a Vallejo-based seismic isolation bearing manufacturer.

PEERNSFEPS

Media Coverage of the Testing

Schedule of Events from May 26, 2010:

10:30 am Welcome and Presentation about the new bridge system by Stephen Mahin (PEER) & Ken Orgozalek (UC Berkeley)
11:00 am View Specimen and Watch Live Shaking Table Demonstration
12:30 pm Lunch and Presentation on "Seismic Isolation for a Resilient and Sustainable Society" by Victor Zayas (EPS)
EPS