A design procedure for pin-supported rocking buckling-restrained braced frames

The paper describes a design procedure for a special type of chevron braced frame endowed with ties between the upper ends of the braces of adjacent storeys. Unlike conventional or suspended zipper braced frames, the braces on one side of the braced spanalong with the adjacent columns and tiesare part of a vertical truss system that is hinged at the base and designed to remain elastic until the near collapse limit state has been reached. The braces on the other side of the braced span consist of buckling-restrained braces and are designed to provide energy dissipation. The design procedure stems from a design method proposed in the past for rocking eccentrically braced structures and applies capacity design principles. The accuracy of the procedure is proved by means of nonlinear dynamic analysis of multistorey systems with different geometric and mechanical properties. To highlight further the qualities of the examined type and evaluate the cost-effective range of application, a comparison is made with other braced types in terms of cost of structural steel and seismic performance.