PERFORMANCE OF SEISMIC RETROFITTED HIGHWAY BRIDGES BASED ON OBSERVATION OF DAMAGE DUE TO THE 2011 GREAT EAST JAPAN EARTHQUAKE

Abstract

 Seismic design technique for bridges has improved gradually based on various experiences of damage from past earthquakes worldwide. Lessons learned from past earthquakes have been reflected in not only the design specifications for newly-constructed bridges but also in the seismic retrofit strategies for existing bridges. The 2011 Great East Japan Earthquake occurred on March 11, 2011 and the catastrophic damage resulting from strong ground motions and the huge tsunami was experienced in the Tohoku and Kanto regions. Since the seismic retrofit project for bridges has been significantly promoted after the 1995 Kobe earthquake, this is the first experience for retrofitted bridges to be excited by a large earthquake.
 To examine the effectiveness of the seismic retrofit of bridges through the 2011 Great East Japan Earthquake experience, the seismic behavior of some retrofitted highway bridges is reported in this paper and the damage compared to the damage found in unretrofitted bridges.