Techniques for seismic safety evaluation and determination concrete strenght of existing reinforced concrete buildings

SUMMARY Nowadays reinforced concrete structures can be used widely because of their economic consideration and the different purposes in our country. However concrete is inherently brittle and performs poorly during earthquakes if not reinforced properly. The recent earthquakes in Turkey dramatically demonstrated this characteristic. The resulting loses and human lives have highlighted the structural inadequacy of buildings to carry seismic loads. Due to actual of earthquake risk, there is an urgent need for assessment of existing buildings in terms of seismic resistance. Considering the huge stock of existing buildings, it is clear that seismic evaluation of these buildings by a detailed structural analysis is practically impossible. So it is inevitable to utilize a quick evaluation method for deciding which buildings need further detailed structural analysis or not and which buildings can be used with their existing seismic safety levels. Buildings which be demanded structural analysis under seismic loads or which have lack of drawing and other documentation, it is necessary further detailed analysis. In these cases, there is a requirement of knowledge about architectural and design plan of building, strength of concrete and bars, location and quantity of bars and geotechnical character. The stages of determination seismic resistance for existing reinforced concrete structures are given in this study. The factors affecting on the compressive strength of core specimens which are used to estimate the compressive strength of hardened concrete in the construction have been investigated with experimental study and empiric formulas has been obtained for various factors. Keywords: Reinforced concrete structures. Rapid evaluation. Seismic performance assessment, Hardened concrete, Destructive method, Nondestructive method.