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A preliminary prediction of seismic damage‐based degradation in RC structures
Author(s) -
Gupta Vinay K.,
Nielsen Søren R. K.,
Kirkegaard Poul H.
Publication year - 2001
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/eqe.45
Subject(s) - structural engineering , stiffness , ductility (earth science) , aftershock , displacement (psychology) , restoring force , yield (engineering) , range (aeronautics) , damping ratio , excitation , degradation (telecommunications) , mathematics , engineering , materials science , creep , physics , vibration , acoustics , electronic engineering , metallurgy , composite material , psychotherapist , aerospace engineering , psychology , civil engineering , electrical engineering
Estimation of structural damage from a known increase in the fundamental period of a structure after an earthquake or prediction of degradation of stiffness and strength for a known damage requires reliable correlations between these response functionals. This study proposes a modified Clough–Johnston single‐degree‐of‐freedom oscillator to establish these correlations in the case of a simple elasto‐plastic oscillator. It is assumed that the proposed oscillator closely models the response of a given multi‐degree‐of‐freedom system in its fundamental mode throughout the duration of the excitation. The proposed model considers the yield displacement level and ductility supply ratio‐related parameter as two input parameters which must be estimated over a narrow range of ductility supply ratio from a frequency degradation curve. This curve is to be identified from a set of recorded excitation and response time‐histories. Useful correlations of strength and stiffness degradation with damage have been obtained wherein a simple damage index based on maximum and yield displacements and ductility supply ratio has been considered. As an application, the proposed model has been used to demonstrate that ignoring the effects of aftershocks in the case of impulsive ground motions may lead to unsafe designs. Copyright © 2001 John Wiley & Sons, Ltd.