Parametric Study on the Behavior of Eccentrically Braced Frame Links
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Date
2021-12
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Addis Ababa University
Abstract
Eccentrically Braced Frames (EBFs) link’s behavior is affected by their link length,
web/flange slenderness, stiffener spacing, stiffener cross-sectional behavior, and the axial
load ratio present in the link. Even though various research has been conducted on the
effect of these parameters on the link’s behavior, a sensitivity analysis to determine
which of these parameters is the most influential on the link’s behavior has not been
conducted. Additionally, most of the previous research conducted on EBF links was
done using the American wide flange sections and not much research has been conducted
using the European IPE sections. The purpose of this research is to conduct a parametric
sensitivity analysis using nonlinear finite element analysis on the behavior of EBF links
made up of European IPE sections subjected to cyclic loading. Latin hypercube sampling
(LHS) method was employed to generate samples for the nonlinear finite element
analysis. A total of 45 samples with 15 samples for each of the three link types (Short,
Intermediate, and Long) was generated. From the nonlinear finite element analysis
results, a sensitivity analysis was conducted using the differential sensitivity analysis
method. From the sensitivity analysis, it was found out that short links plastic rotation
capacity was the most influenced by axial load ratio and stiffener spacing, while their
overstrength ratio was the most influenced by stiffener spacing and link length ratio.
Short link energy dissipation capacity and ductility were the most influenced by axial
load ratio, link length ratio, and stiffener spacing. Intermediate links plastic rotation
capacity and ductility were the most influenced by stiffener spacing, axial load ratio, link
length ratio, and flange slenderness the most. Intermediate links’ overstrength ratio was
the most influenced by stiffener spacing and link length ratio, while their energy
dissipation capacity was the most influenced by stiffener spacing and flange slenderness.
Long links’ entire behavior was influenced by their flange slenderness and axial load
ratio the most. It was also observed that tensile axial load increases the overstrength ratio
in short links. The higher overall overstrength ratio observed for IPE sections in previous
research was also observed in this research as well where most of the samples surpassed
the seismic code recommended value of 1.5.
Description
Keywords
Eccentrically braced frames, Links, axial load ratio, Link length ratio, Web slenderness, Flange slenderness, Stiffener spacing, Plastic rotation capacity, Overstrength ratio, Ductility, Energy dissipation capacity, Cyclic Loading