Structural Performance Evaluation of 90 RC Buildings Collapsed during the 2011 Van, Turkey, Earthquakes

Abstract

The structural performance evaluation is presented of 90 reinforced concrete (RC) buildings that collapsed during the October 23 (Erciş) and November 9 (Edremit), 2011, earthquakes in Van, Turkey. A total of 35,000 buildings are damaged or collapsed in the city center and surrounding villages after the Erciş and Edremit earthquakes. Almost all the RC buildings are affected in the region. To evaluate the structural performance of the collapsed buildings, the buildings are evaluated according to structural system properties, specification properties, material properties (concrete and reinforcement steel properties), and soil properties. The results showed that a large proportion of nonengineering RC buildings completely collapsed or were damaged heavily. Most of the RC buildings in the affected area are not designed and constructed in accordance with Turkish code. Also, it was found that 26% of the buildings do not have a building license, 66% of the buildings’ ground floors were used as a commercial or retail space, 36% of the buildings lacked any structural design, 57% of the buildings were not constructed in accordance with their structural drawings, 74% of the structural drawings did not have any detail drawings and beam/column confined zones, the concrete used in many buildings did not have adequate compressive strength, aggregate dimensions were larger than the maximum aggregate diameter for concrete, 60% of the buildings were constructed with unribbed reinforcement steel, and the majority of the buildings (85%) did not have any geotechnical report.