Comparison of New-Generation Elastic and Design Response Spectra Eurocode 8 with Currently Valid Norm in Terms of N2 Method

Abstract

The new generation of Eurocode standards has prompted enquiries regarding the major distinctions from the current version, particularly in relation to the application of the N2 method. A substantial change has been made to the definition of elastic spectra. The new spectra are defined through a series of fixed, probabilistically determined points, yet they remain rooted in a probabilistic approach. Three building types—multi-storey reinforced concrete (RC) frames, steel moment frames, and steel braced frames—were analysed in accordance with ground accelerations of 1, 2, and 3 m/s2, as well as across five soil types (A–E). Variations in target displacements between soil types, particularly A, B, and D, are notable in the results. For accelerations of 2 and 3 m/s2, steel structures demonstrate consistent displacements, whereas RC frames exhibit values that are up to 20% higher, particularly on soils C and E. For soils A and B, the distribution of inter-storey drift remains consistent. Nevertheless, in the case of 1 m/s2, the utilisation of next-generation spectra results in an average 46% decrease in inter-storey drifts. The significance of adapting design methods to the updated Eurocode provisions is underscored by these findings, which emphasise the substantial influence of soil type on building response and safety performance, particularly under increased seismic demands.