Designing, testing and modelling two innovative non-conventional buckling restrained braces for seismic resistant buildings

Resumen

In this thesis two all-steel BRB have been designed, manufactured and tested, and both satisfy the testing protocols required by EU and US codes. They are composed of a steel slotted restraining unit which stabilizes the steel core. The first one, the Modular Buckling Restrained Brace (MBRB), is composed by several seriated modules which contain several dissipation units connected in parallel, which yield under shear forces. Although it has good hysteretic response and a high ductility, its core is heavy and expensive to manufacture. The second one,the Slotted Buckling Restraining Brace (SBRB), solves these two shortcomings. It yields under axial forces, like the conventional BRBs, but the usual solid core has been substituted by a perforated plate. The core is a one-piece element composed of two lateral bands, of a nearly uniform section and designed to yield, connected by stabilizing bridges, which behave elastic. The buckling prevention of the lateral bands is done by the restraining unit and the stabilizing bridges. Design expressions have been proposed to design both devices, and a numerical material model have been formulated and implemented in commercial finite element method software to numerically simulate the behavior of the braces, which will reduce the need of full scale tests for its design