TITLE:
Simulating the Seismic Response of Concentrically Braced Frames Using Physical Theory Brace Models
AUTHORS:
Liang Chen, Lucia Tirca
KEYWORDS:
Brace Model; Plastic Hinge; Hysteretic Energy; Seismic Response; Time-History Analysis
JOURNAL NAME:
Open Journal of Civil Engineering,
Vol.3 No.2A,
June
18,
2013
ABSTRACT:
The aim of this paper is to assess the accuracy of brace
models formulated in Drain 2DX and OpenSees by comparing the simulated results with those obtained from experimental
tests. Both, Drain 2DX and OpenSees rely on the physical theory brace model. In
this study, experimental tests conducted on the behaviour of structural hollow
section braces subjected to symmetric and asymmetric quasi-static cyclic
loading were selected for calibrating the numerical model. In addition, the
predicted failure strain parameter resulted from a proposed empirical equation
as a function of slenderness ratio, width-to-thickness ratio and steel
properties was used to define the low-cycle fatigue material that was assigned
to model braces in OpenSees. It is concluded that both Drain 2DX and OpenSees
brace models give a good prediction in terms of maximum tensile and buckling
force, as well as interstorey drift. However, in Drain 2DX, the brace model is not able to replicate the out-of-plan buckling and the braced
frame model cannot provide an accurate response when the system experiences
highly nonlinear demand. To emphasise the differences in performance between Drain
2DX and OpenSees, the behaviour of a 4-storey concentrically braced frame with
zipper bracing configuration, located in Victoria, BC, was
investigated.