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  • Seismic design methods of concentrically braced steel frames

    SUMMARY – The work described here is addressed to the evaluation and the comparison of different seismic design methods of multistory steel frame structures with concentric braces. In particular, a multistory frame is designed through both the simplified method currently proposed by the recent code provisions (OPCM 3431, DM 24/01/2008, Eurocode 8 ) and an alternative simplified one, based on the partial contribution due to the brace under compression. The assessment of the seismic response of the two structures is then performed by means of static analyses, where the non-linearities of the geometry and of the materials are included, in order to compare the related seismic performances. In addition, the seismic response of the frame designed with the new method is assessed through non-linear dynamic analyses and incremental dynamic analyses, to particularly highlight the properties of the alternative adopted method, which permit to achieve less conservative solutions, more economical in terms of amount of material and characterized by more effective collapse mechanisms.

    For this paper is available an extended abstract after the text in Italian

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  • Nuovi strumenti per lo studio della risposta sismica di strutture irregolari in pianta

    SUMMARY – New tools for the analysis of the seismic behaviour of plan-asymmetric structures are herein presented and discussed. In particular, the concept of Polar Spectrum is firstly introduced to feasibly describe the spatial features of the seismic event. Limit domains are then used to investigate the non-linear behaviour of plan-asymmetric structures. The results obtained by the discussed procedure have been compared with non-linear dynamic analyses by using a benchmark structure.

    This paper is available in Italian only.