Assessment of the Design Provisions for Steel Concentric X Bracing Frames with Reference to Italian and European Codes

Beatrice Faggiano*, Luigi Fiorino, Antonio Formisano, Vincenzo Macillo, Carmine Castaldo, Federico M. Mazzolani
Department of Structures for Engineering and Architecture, University of Naples “Federico II”, Naples, Italy.

Article Metrics

CrossRef Citations:
Total Statistics:

Full-Text HTML Views: 811
Abstract HTML Views: 1055
PDF Downloads: 508
Total Views/Downloads: 2374
Unique Statistics:

Full-Text HTML Views: 369
Abstract HTML Views: 584
PDF Downloads: 328
Total Views/Downloads: 1281

Creative Commons License
© 2014 Faggiano et al;

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Structures for Engineering and Architecture, University of Naples “Federico II”, Naples, Italy; Tel: (+39) 081.7682447; E-mail:


In the field of construction in seismic areas, the current Italian technical code for constructions NTC2008 is substantially based on the design criteria of Eurocode 8 (EC8), although with some differences. Focusing on steel structures with X Concentric Braces (CB), which is one of the most common seismic resistant structural typology in steel buildings, the paper illustrates a critical review of design methodologies specified in NTC2008, with the intent of providing simplified and more efficient design criteria and procedures able to ensure adequate safety levels under seismic actions, according to the modern design approach. The study is divided in two parts. The first part consists in the design according to the standard rules of typical steel X braced structures by linear analysis, both static and dynamic. The aim is identifying any possible weakness in the current design criteria, with particular reference to both the applicability of the proposed procedures and the actual possibility to size the bracing cross-sections and the connected structural members, like beams and columns. The second part consists in the assessment of the seismic response of structures examined. To this purpose, non-linear static analyses are performed in order to evaluate the most relevant behavioural issues, like the behaviour factor, the failure modes and the effectiveness of the capacity design criteria. Based on the results obtained, a proposal for the enhancement of design criteria is presented.

Keywords: Behaviour factor, concentrically braced frames, non linear static analyses, overstrength factor, eismic design criteria, seismic resistant steel structures.