Determination of mechanical properties of concrete and steel materials taken from buildings in Antakya after the Kahramanmaraş earthquakes

The Kahramanmaraş earthquakes that struck the Antakya downtown resulted in significant structural damage, highlighting the need to understand the underlying causes and develop effective mitigation strategies. This experimental study aims to investigate the reasons behind the observed structural damage by examining defects in building materials. Through comprehensive laboratory testing, a detailed analysis was conducted to identify the factors contributing to the vulnerability of structures in the affected area. To simulate the conditions experienced during the earthquake, various building materials, including concrete and reinforcement steel, were subjected to rigorous testing. The results revealed variations in concrete quality, with some samples exhibiting lower compression strength, incorrect aggregate mixing ratios, deepening of carbonation over time and higher permeability, indicating potential weaknesses in the structural integrity. Furthermore, the examination of reinforcement steel samples revealed the presence of corrosion and inadequate bond strength, compromising the load-bearing capacity of the structures. These defects significantly affected the performance of reinforced concrete elements during the earthquake, leading to localized failures and increased vulnerability. In addition to these tests, cylindrical concrete elements with the same properties were reproduced to examine the concrete-steel adhesion interface. Ø8 reinforcements collected from the field was placed in the concrete elements during the production phase. Tensile tests were carried out on 48 test samples produced. In particular, pull-out tests of test elements without ribs and with low concrete compression strength, simulating the field, were completed at very low loads. The experimental results provide valuable insights into the causes of structural damage observed in the Hatay region following the Kahramanmaraş earthquakes. The identified defects in building materials, such as concrete and reinforcement steel, highlight the importance of stringent quality control measures during construction.