I.11.07: Pre‐test numerical simulations for development of prequalified buckling restrained braces

Abstract

ABSTRACTBuckling Restrained Braces (BRBs) are increasingly used as structural fuse elements due to their stable and quasi‐symmetric cyclic behaviour and capacity to dissipate a large amount of energy. However, a wider adoption of buckling restrained braced frames is often precluded by the proprietary character of most BRBs, need for their experimental qualification and sometimes lack of experience of designers. To overcome these problems, a set of typical BRBs were developed in view of their pre‐qualification. “Conventional” and “dry” devices were considered, with capacities corresponding to typical steel multistorey buildings in Romania. The paper presents the pre‐test numerical simulations program for the “conventional” type of BRBs. The numerical model was developed using the general‐purpose finite element analysis program ABAQUS. The nonlinear cyclic behaviour of the steel core was described by a combined kinematic‐isotropic hardening rule. Calibration of the hardening parameters is also presented. A parametric analysis was performed in order to identify the optimal geometry and mechanical characteristics of brace components. Core aspect ratio, gap size, critical elastic axial load of the buckling‐restraining mechanism were among the investigated geometrical parameters. Also, different values for the friction coefficient were analysed. Outcomes of the finite element investigation were used developing the engineering solution and a design procedure for two conceptually different solutions of “conventional” buckling restrained braces in view of pre‐qualification.