Bridge Performance during the 2010 M8.8 Chile Earthquake

Field observations and plausible reasons of damaged bridges are presented and their implications to bridge design are discussed. In general, bridge substructures behaved satisfactorily except that a few columns suffered shear failure. Reinforced concrete shear keys served their design purposes, performing well when they functioned as part of the lateral restraint system at the bottom flange of girders. Vertical seismic bars were widely used to restrain the vertical motion of decks and they also performed well. Lateral steel stoppers were also used to provide vertical and lateral restraints on girders but were largely unsuccessful due to their weak connection to capbeams. Many spans of precast, prestressed, discontinuous girder bridges with continuous decks fell from their supports due likely to significant rotation of their superstructure. Other types of bridge damage were related to ground shaking, ground settlement and liquefaction-induced lateral spreading.