SEISMIC PERFORMANCE EVALUATION OF RESIDENTIAL RC TEMPLATE BUILDINGS USING NON-LINEAR ANALYSES PROCEDURES

Abstract

Recent damaging tremors in the Balkans have shown insufficient earthquake performance of reinforced concrete (RC) buildings intended for residential purposes. In Albania, typified designs developed by the governmental authorities during the socialist era are used for many of the buildings intended for residential and governmental services including administrative centers, health clinics, hospitals, and schools as a common practice to save on architectural fees and confirm quality control. Therefore, such template-designed buildings must be dealt with first. This thesis assesses the seismic performance of residential buildings with the chosen template designs in Albania considering the inelastic response of RC sections. Five residential buildings with template designs were chosen to represent an important percentage of residential buildings in mid-size cities located in high seismic districts of Albania. Selection of template designed buildings and material properties were based on site investigation on residential buildings in several cities of the region. Pushover curves of studied buildings were constructed by nonlinear static and incremental dynamic analyses conducted in two orthogonal directions. The nonlinear dynamic characteristics were represented by equivalent single-degree-of-freedom (ESDOF) systems and their earthquake deformation demands were estimated under selected ground motions represented by near and far fault recordings. Seismic performance evaluation was carried out in accordance with modern seismic guidelines following the capacity spectrum method. Reasons of building damages during the November 26, 2019 earthquakes are examined using the results of the performance assessment of studied buildings. The effects of material quality and detailing effect on the earthquake performance of residential RC buildings were investigated. The detailed examination of capacity curves and performance evaluation identified deficiencies and possible solutions for template designs. Earthquake capacity evaluation was deployed in accordance with capacity spectrum method. Evaluation of the capacity curves for the investigated typologies points out that concrete quality and detailing have remarkable effects in both displacement and lateral load bearing the capacity of buildings. The unsatisfactory performance of residential buildings makes the development of effective and affordable retrofitting techniques essential. The rehabilitation techniques are broken into two different categories: the local methods, which improve the response of individual structural elements and the global ones, which operate on the whole structure. Since in Albania poor material and construction quality is common problem, the most suitable technique is the use of additional shear walls to increase lateral load capacity and decrease deformation demands. As a result, existing weaknesses in frame elements would be less pronounced and poor construction quality in buildings could be somewhat compensated. Finally, conclusions are provided, and future research needs on the topic are outlined.