A Failure Mechanism Seen After the February 6th, 2023 Kahramanmaraş Earthquake Sequence, Buckling of Compression Reinforcement in RC Beams

Two catastrophic earthquakes occurred in the Eastern Anatolian Fault Zone on February 6, 2023, in the city Kahramanmaraş in Türkiye and directly affected the Eastern and South-Eastern Anatolia regions, where 15 million people live. These earthquakes are among the most destructive earthquakes in the history of Türkiye and destroyed both old and new structures. While many studies have been conducted to report the caused damage in the existing building stock, common damage is worth in-depth discussion since it was observed in the seismic code-compliant new buildings. This damage is the buckling of compression reinforcement (BCR) in reinforced concrete beams. In this study, the observed damage mechanism has been evaluated with the design requirement of the recent seismic codes of Türkiye. The principles of anti-buckling design requirements in literature were searched and a certain deficiency in the codes was revealed. The outcomes of the study have been applied to an existing newly constructed reinforced concrete building that experienced BCR damage in its beam. It has been demonstrated that beams designed according to Türkiye’s recent seismic codes may fail to reach the ductility level specified in the literature due to buckling of their compression bars under extreme loading.