To improve the predictability of structural and non-structural damage of structures
for a given hazard scenario, it is essential to identify factors that influence the
response and evaluate their contribution. Several studies have therefore focused on the
assessment of parameters that influence the inelastic response of structures under
seismic loading. However, these studies have in most cases been limited to single
degree of freedom (SDF) systems and generic frames with controlled strength and
stiffness distribution characteristics. In addition to this, the influence of the frequency
content of ground motion on the inelastic response of structures has not been fully
explored and utilized. Therefore, this thesis aims to understand the influence of
frequency content and key properties of structure, designed to Eurocode provisions,
on the inelastic response.
A suitable frequency content measure that can be related to magnitude, distance
and site characteristics of an earthquake event, and easily adopted as a design input, is
selected from the available literature in order to understand the influence of frequency
content. The applicability of the selected parameter is first explored and established
by studying the inelastic displacement demand of SDF systems as well as global drift,
base shear and maximum storey drift profile of a selected multi-degree freedom
(MDF) system, using a suite of 128 far-field ground motion records. Subsequently,
incremental dynamic analysis of a large set of moment resisting steel frames designed
to Eurocode 8 is conducted using 72 far-field ground motion records. The influence of
salient structural properties on the inelastic drift and strength demands and their
interaction with frequency content is investigated. Based on extensive parametric
studies, regression models are developed as a function of the parameters that influence
drift and strength demands of the frames.
Finally, implications of the findings on current seismic design and assessment
provisions, with emphasis on the guidelines of Eurocode 8, are discussed.
Furthermore, recommendations are proposed for future work that can lead to further
improvements in codified procedures.