Comparative Study of the Interaction Diagrams before and after Retrofitting the Existing Reinforced Concrete Columns of the National Gallery of Arts Building in Tirana

This study presents a comprehensive analysis of the structural integrity and performance of Reinforced Concrete (RC) columns in the National Gallery of Arts in Tirana before and after undergoing retrofitting procedures. The focus is on the interaction diagrams, crucial for understanding the axial load-bending moment relationship in RC columns. The retrofitting process must use contemporary techniques suitable for historical and culturally significant buildings. This study's chosen retrofitting approach involved applying concrete jacketing and steel rebars. This strategy aimed to bolster the columns' structural stability and seismic resilience while meticulously preserving the building's architectural essence. The comparison between the pre- and post-retrofitting diagrams provided a valuable understanding of the effectiveness of the retrofitting techniques. Significant improvements were observed in the load-bearing capacity and flexibility of the columns, bolstering their ability to resist axial forces and bending moments. The columns' axial force-bearing capacity increased by more than four times, and the capacity against bending moments increased by 5.8 to 8.6. Furthermore, the findings contribute helpful insights to the field of structural engineering, particularly in the context of retrofitting and conserving ageing structures in urban environments, offering a methodological approach for enhancing the structural integrity of RC columns in heritage buildings. This paper explores the impact of retrofitting reinforced concrete columns with reinforced substantial jackets on their interaction diagrams.