Seismic performance and cost comparative analysis of steel braced frames designed in the framework of EC8

The paper investigates the seismic performance and the cost of case-study buildings embedding different braced steel structures, namely concentrically braced frames, eccentrically braced frames with short or long links, braced frames with buckling restrained braces or double-stage yield buckling restrained braces and dual systems consisting of braced frames with buckling restrained braces and moment-resisting frames with semi-rigid connections. The structures are designed by means of the design prescriptions of Eurocode 8, when available, or according to design procedures proposed by the authors in the framework of the Eurocodes. The seismic response of the structures is determined by incremental nonlinear dynamic analysis considering the effects of the variability of the dynamic properties of the seismic input and the variability of the mechanical properties of steel. The seismic performance is assessed in accordance with Eurocode 8 prescriptions. The results are used to compute the fragility curves of the case-study structures and the mean annual frequency of exceedance of the damage limitation, significant damage and near collapse limit states based on the hazard model proposed in Eurocode 8.