Structural Performance of Bridges in the Offshore Maule Earthquake of 27 February 2010

Of the nearly 12,000 highway bridges in Chile, approximately 300 were damaged in this earthquake, including 20 with collapsed spans. Typical failure modes include damage to connections between super- and substructures, unseating of spans in skewed bridges due to in-plane rotation, and unseated spans with some column damage due to permanent ground movement. Unusual failure modes include unseating of spans in straight bridges due to in-plane rotation, plate girder rupture due to longitudinal forces, scour and pier damage due to tsunami action, and collapse of a historic masonry bridge. The most common damage mode was the failure of super-to-substructure connections (shear keys, steel stoppers, and seismic bars), which is the most likely reason for the low incidence of column damage. Whereas the fuse-like behavior of these components is believed to have protected the columns, the lack of adequate seat widths led to the collapse, or imminent collapse, of many superstructures.