The collapse of the Alto Rio building during the 27 February 2010, Maule, Chile earthquake

The Alto Rio building, a fifteen-story building located in Concepción, Chile, collapsed during the 2010 Maule, Chile, Earthquake. Construction of the building was completed in 2009 following the Chilean building code of 1996. The building was provided with structural reinforced concrete walls (occupying 7% of the floor area) to resist lateral and vertical loads. The walls failed in the first story causing the overturning of the entire building. Analyses show that the building was more likely to form a failure mechanism in the second story than in the first story. The inconsistency between analysis results and field evidence implies that the strength of the first story was reduced by factors not considered in conventional analysis. Furthermore, field observations indicate that bond failures occurred in lap splices in the first story. These observations and the analysis results suggest that bond failure in the first story is likely to have triggered the collapse.