Energy-related parameters and structural damage in nonlinear dynamic analysis

Abstract

Non Linear Dynamic Analysis (NLDA) is increasing its popularity not only for research but also for the Performance-Based Design (PBD) and analysis of actual buildings. The standards and codes offer guidance and minimum requirements to perform NLDA, however, many aspects are open to expert judgement and such is the case of the input ground motions choice. In the Eurocode 8 (EC8), for example, a set of ground motions, artificial or recorded, can be selected and scaled so that their response spectra approximately characterise the desired target spectrum, and for this purpose, the spectral matching techniques are becoming more popular. This study aims to assess the influence of energy-related parameters, such as the significant duration (𝐷��𝐷��𝑎��𝑎��5−95) and Arias Intensity (𝐼��𝐼��𝑎��𝑎��) of spectrally matched records, on the NLDA damage results in terms of the well-known Park and Ang damage index. Particularly, variations in the damage of a real building were studied using a set of four different seismic records spectrally matched to several EC8 design spectra. The results show significant differences in the damage produced by the spectrally equivalent records. Records with larger energy input lead to greater damage compared to the shorter and less energetic records. It is concluded that the energy-related features of the input records might have more impact on the structural damage than the acceleration-related ones.