Recorded and Numerical Strong Motion Response of a Base-Isolated Bridge

• Published in: Earthquake Spectra
• Main Authors: Bessason, B., Haflidason, E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: SAGE Publications 2004
• Subjects: Iceland
• Online Access: http://dx.doi.org/10.1193/1.1705656; http://journals.sagepub.com/doi/pdf/10.1193/1.1705656

Since 1983, 12 Icelandic bridges have been base isolated for seismic protection. Lead-rubber bearings have been used in all the cases. The Thjorsa River Bridge, built in 1950 and retrofitted with base isolation in 1991, is instrumented by strong-motion accelerometers. The bridge has one 83-m-long main span and two 12-m-long approach spans. Only the main span, a steel arch truss with concrete deck, is base isolated. In June 2000, two major earthquakes of magnitude 6.6 and 6.5 occurred in South Iceland; the epicenter was close to the Thjorsa River Bridge. In the first earthquake, a peak ground acceleration of 0.53 g was recorded at the bridge site, and in the second earthquake, a peak ground acceleration of 0.84 g was recorded. The Thjorsa River Bridge survived the earthquakes without any serious damage and was open for traffic immediately after the earthquakes.