Multi-Code Response Spectrum Analysis of a Ten-Storey Reinforced-Concrete Building

Abstract This thesis examines the seismic response of a reinforced concrete tower with ten storeys above ground and two underground floors, designed for construction in Albania. The analysis focuses on how different seismic codes influence design outcomes, comparing Eurocode 8 (EC8), the Italian NTC2018, and the older Albanian KTP-89. The methodology is based on response spectrum analysis, carried out in SAP2000. The process began with the definition of materials, load patterns, and seismic input spectra for the three codes. A modal analysis was first performed to identify natural periods and mode shapes, followed by response spectrum analyses applied in both principal directions. From these, the study extracted global results such as base shear, roof displacement, and interstorey drifts, as well as local forces in beams, columns, and walls. Reinforcement demands were then calculated in line with Eurocode 2 design provisions. The results show that EC8 and NTC2018 produce similar outcomes, with higher seismic demands and reinforcement quantities, reflecting their common reliance on modern, site-specific spectra. By contrast, KTP-89 systematically underestimates seismic effects, due to its simplified zonation approach and absence of detailed soil amplification. While this may appear economical in terms of material use, it reduces safety margins and does not represent the real hazard conditions of Albanian sites. The study concludes that modern codes not only provide safer and more reliable designs but also align Albania with European practice. KTP-89 remains relevant only as a historical reference for assessing older structures. The comparison highlights the importance of updating national standards, since code choice directly influences both construction cost and structural resilience.