VULNERABILITY ASSESSMENT OF CURRENT MASONRY BUILDING STOCK IN ALBANIA

Abstract

Recent devastating earthquakes in Albania have shown the inadequate seismic performance of existing building stock. In Albania, template designs developed by the General Directorate of Construction Affairs are used for many of the buildings intended for residential as well as governmental services (administrative centers, health clinics, hospitals, schools etc.) as common practice to save on architectural fees and ensure quality control. For that reason, these buildings must be dealt with firstly. This study evaluates seismic performance of residential buildings with the selected template designs in Albania considering inelastic behavior of masonry components. Nineteen masonry buildings from ten different template designs were selected to represent major percentage of residential buildings in medium-size cities located in high seismic regions of Albania. Selection of template designed buildings and material properties were based on field investigation and a detailed archive study on public and private buildings in several cities of Albania. Capacity curves of investigated buildings were determined by pushover analyses conducted in two principal directions by using TREMURI software package. The inelastic dynamic characteristics were represented by equivalent single-degree-of-freedom (SDOF) systems and their seismic displacement demands were calculated under selected ground motions from near and far-field recordings. Seismic performance evaluation was carried out in accordance with Eurocode 8 that has similarities with FEMA-356 guidelines. Reasons of building damages in recent earthquakes are examined using the results of performance assessment of investigated buildings. The effects of material quality, building height, the date of construction on the seismic performance of residential buildings were investigated. The detailed examination of capacity curves and performance evaluation identified deficiencies and possible solutions for template designs. Seismic capacity evaluation was carried out in accordance with Eurocode 8. Evaluation of the capacity curves for the investigated buildings points out that material quality, detailing, aging and height have significant role in both displacement and lateral strength capacity of buildings. Also, performance of public buildings improves as the amount of load bearing wall increases, emphasizing its importance, especially in countries where construction with poor detailing is a common problem. Insufficient performance of residential buildings makes the development of the effective and affordable retrofitting techniques essential. The most convenient technique in Albania where poor material and construction quality is a common problem, seems the adding steel grids to increase lateral load capacity and decrease displacement demands. Besides this technique, adding encirclements and polymer grids could be alternative methods to increase the stiffness and the deformation capacity of the existing masonry buildings. As a result, existing deficiencies in load bearing walls are less pronounced and poor construction quality in buildings is somewhat compensated. Analytical findings of this study are also compared with the induced damages on masonry buildings after 2019 Albanian Earthquakes. Finally, conclusions are provided, and future research needs on the topic are outlined.