|
|
||
|
|
|
|
This and the next image are from:
P.C Ashwin Kumar, Dipti Ranjan Sahoo & Nitin Kumar (Dept. of Civil Engineering, Indian Institute of Technology Delhi, India),
“Limiting slenderness ratio for hollow square braces in special concentrically braced frames”, Proceedings of the Tenth Pacific Conference on Earthquake Engineering Building an Earthquake-Resilient Pacific 6-8 November 2015, Sydney, Australia
ABSTRACT: Special concentrically braced frames (SCBFs) are commonly used to resist lateral forces in structures located in high-seismic regions. Steel braces undergo inelastic axial deformations and thus provides an adequate level of structural ductility and hysteretic energy dissipation capability to the frame under cyclic loading. Past studies have shown that the slenderness ratio and the width-to-thickness ratio of braces are primarily responsible for achieving enhanced seismic response in SCBFs. An increase in the brace slenderness ratio results in a reduction in its energy dissipation capacity along with a simultaneous increase in the ductility nearing its fracture. Since both energy dissipation capacity and ductility of braces are essential parameters in quantifying the seismic performance of SCBFs, there is a need of establishing the optimum range of brace slenderness ratio and width-to-thickness ratio. The main objective of this study is to find an optimum range as well as the lower limits of these parameters for braces of hollow square steel (HSS) sections. An extensive finite element (FE) parametric study has been conducted on a wide range of values of these parameters using a commercial software package ABAQUS. The FE models accounts for the inelastic hysteretic characteristics and the fracture behavior of braces. The results of simulation models matched very well with the past experimental results with respect to the performance points, namely, global buckling, local buckling, fracture initiation, complete fracture and ductility. Finally, the relationship between the lower limit of slenderness ratio and the width-to-thickness of square braces has been established based on the simulation results.
Page 172 / 216