Observations on the Van Earthquake and Structural Failures

Abstract

Turkey is located in one of the most seismically active regions in the world. In the 1999 Marmara earthquake in Turkey, more than 20,000 people died. On October 23, 2011, an earthquake with a magnitude of 7.2 on the Richter scale struck the Van and Ercis cities, causing more than 600 casualties. The epicenter was located in Zone 1 in the earthquake zones map of Turkey. In this paper, the results of a field reconnaissance survey of the affected earthquake area were reported and common structural failures in reinforced concrete (RC) structures were summarized. The observed failure modes included weak column–strong beam formations, hinging in the columns, column–beam joint failures, lap splice inadequacies, poor concrete quality, insufficient transverse reinforcement, buckling of longitudinal column reinforcement, pancake type of collapse mechanism, soft- and weak-story failures, and short column formations. The buildings in Van and Ercis have also several undesired architectural features, such as the presence of mezzanine floors and penthouses, commercial use of ground floors, etc.