Gradient-based study on seismic performance reduction of steel braced frames due to irregular brace over-strength distributions

Abstract

In this paper a general sensitivity-based gradient methodology developed to investigate the relation between seismic performance reduction and regularity of brace overstrength distributions is used for performance-based design and assessment of braced steel frames. A range of variation of the brace over-strength is defined and the brace over-strength patterns that are the most unfavorable for each response parameter are identified. Then, the relationship between the brace over-strength used in the seismic design and the maximum seismic performance reduction is obtained. Results for a case study considering a realistic buckling-restrained braced frame are presented and discussed showing the practical use of the developed sensitivity-based gradient methodology.