Assessment of Current Non-linear Analysis Models used in Earthquake Engineering
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Date
2019-09
Authors
Journal Title
Journal ISSN
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Publisher
Addis Ababa University
Abstract
The study aims to evaluate existing numerical nonlinear modeling techniques used in the
seismic analysis to provide a common ground for applications of the models in earthquake
engineering. Comparative analysis carried out to further asses the existing nonlinear
numerical finite element modeling techniques for beam-column elements subjected to
lateral loading. First, experimentally tested RC bridge column specimens downloaded
from peer structural performance database and modeled in OpenSees finite element
software.
The study shows, for sections exhibiting strain hardening behavior, the distributed forcebased
fiber
models
provide
a
more
accurate
response.
The
response
computed
using
the
distributed
displacement-based fiber models overestimate the capacity of the members.
Therefore, to accurately describe the inelastic response, several displacement-based
elements are required.
For the section exhibiting strain-softening behavior, the localization issue affected both
the displacement-based and force-based formulations. Therefore, material regularization
is required to overcome mesh dependent response. Furthermore, for section showing
softening behavior, the regularization of both concrete and steel materials is required. The
concentrated force-based plastic hinge model adequately captures the nonlinear response.
The lumped plasticity with zero-length hinge model captures the initial stiffness
adequately, but, inadequate to capture the cracking and onset of overall yielding.
Furthermore, the model underestimates the ultimate capacity in terms of base shear.
Finally, to evaluate the numerical accuracy of the models, two-story and three-story RC
frames modeled in OpenSees finite element software. For nonlinear analysis of the RC
frames, the distributed force-based fiber models capture the inelastic response accurately.
Increasing the axial load on the two-story RC frame exhibits mesh dependent results. For
the frame under strain-softening behavior, the material regularization techniques
successfully tackle the localization issue.
Description
Keywords
Earthquake Engineerin, Non-linear Analysis Models