Finite Element Parametric Studies on Buckling Restrained Brace

Abstract

Concentric Braced Frame (CBF) is an efficient lateral load resisting system. It adds stiffness and strength to the structural system. However, the repeated failures of concentric braces in the past earthquakes has raised concern of its overall seismic performance and ultimate deformation capacity. Buckling Restrained Brace (BRB) is becoming popular energy dissipation device in the field of seismic resistant steel structures. BRB absorbs substantial amount of energy during cyclic performance. By preventing the buckling of the brace, a symmetric and stable hysteresis curve of BRB is achieved, as it dissipates high amount of energy in every single cycle. In the present research work, numerical modelling, and prediction of cyclic response of concrete BRB is presented. The numerical model is validated by comparing the results with the previous experimental work. Numerical simulations have been performed using the finite element software ABAQUS. The yielding core length is varied from 1m to 3 m, and the coefficient of friction is varied from 0 to 1. The parametric study is carried out to investigate the influence of yielding core length and coefficient of friction on the hysteretic performance of concrete BRB. The performance of all the numerical models is accessed by comparing their hysteretic response and the compression adjustment factor. With increasing the friction coefficient between the steel core and the concrete, an unsymmetrical hysteretic response is observed, with reduction in energy dissipation. Axial stiffness of short length BRB is found to be higher, as compared to the longer length. From the parametric study, it is revealed that the length of the yielding core and friction impact the cyclic response of BRBs