Observations from the February 27, 2010, earthquake in Chile

On February 10, 2010, Chile was struck by an 8.8-magnitude earthquake, followed by hundreds of aftershocks. This article summarizes findings from a reconnaissance team from the Precast/Prestressed Concrete Institute that visited the region in April 2010 to assess damage. The team found that most structures performed acceptably or better, with the number of deaths and the amount of property loss proportionate to the severity of the earthquake. Precast concrete building systems generally performed well. The absence or weakness of diaphragm framing did result in local failures. Although bridges experienced shaking that was much more intense that the bridges were designed to handle, most precast concrete bridges performed well. However, the bridges that suffered the most damage were those that were designed based on a recent (1990s) practice that eliminated or reduced diaphragms providing lateral support between beams. These bridges experienced lateral displacements at the bearings, failure in end stoppers and overturning of some beams. Steel-girder bridges constructed with similar end details experienced similar failures. As a result of the earthquake, changes were made to Chile’s building code. Similar changes are being considered for possible inclusion in the American Concrete Institute Building Code 318-08 section 21.9 on special structural walls and coupling beams.