Analysis of the seismic performance reduction in steel braced frames due to irregular brace over-strength distributions

The influence of brace over-strength distributions on the seismic response of steel braced frames is studied through a method based on response sensitivity computation. A range of variation of the brace over-strength is defined and the brace over-strength patterns that are the most unfavourable for each damage measure 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 steel frame are presented and discussed showing the use of the developed sensitivity-based methodology.