Re-examination of damage distribution in Adapazarı: Structural considerations

Adapazarı was the scene of spectacular structural damage as well as widespread foundation displacement that occurred in the city during the devastating earthquake of August 17, 1999. The damage patterns observed in Adapazarı were quite peculiar, so these are re-examined in an effort to answer the question of whether they are indicative of a consistent trend in terms of the building attributes and/or site conditions. For this purpose two databases comprising buildings surveyed in Adapazarı after the earthquake have been re-evaluated. The first data set included buildings that had collapsed fully; hence no complete data on the as-built properties have been assembled. Their examination was necessarily a desk study conducted from the design blueprints of the individual buildings that no longer existed. The second source was a larger database comprising buildings that had experienced various levels of damage and examined using conventional evaluation procedures. All buildings were rated from the viewpoint of conventional seismic performance using accepted parameters to confirm the observed damage. An examination based solely on structural attributes leads us to believe that building collapses observed in Adapazarı are perhaps too involved to reduce to a few simple deficiency attributes. The site effects seem to have played a major role in the observed damage, because conflicting trends of structural attributes and the actual damage were established. A companion paper focuses on the influence of site effects on the observed building damage.