Effects of Local Eccentricity of Connecting Braces on Nonlinear Behavior of Steel Concentric Brace Connections

According to most current building codes, in order to prevent a steel brace from brittle behavior due to buckling, it is necessary to use prescribed stronger and stiffer sections. However, experience from past earthquakes has shown that the above requirement is not effective in containing the brittle failure of members, not even in postponing this unwanted behavior. It is well known that one of the factors affecting dynamic behavior of a brace is its end condition, i.e., the stiffness of connection plates known as gusset plates (GP). In this paper through numerical simulation it is suggested to offset the connecting members at the connection to enhance the ductility and even strength of the connection itself. For the purpose of this research work, numerical models are studied using nonlinear static analysis. A very good match is shown to exist between results of computer simulation and experimental results, making it possible to study much more models at less time, effort, and cost, comparing to experimental work. A summary of results from numerical modeling and nonlinear analysis on ۵ different connection configurations of cross and chevron bracing is also given and compared. It was shown that the eccentricity at connecting point is resulted in increasing ductility.

Keywords:

Brace Connections , Nonlinear behavior , Local Eccentricity , Steel