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A research project was conducted at University of Naples “Federico II” over the last few years with the aim to give a contribute to overcome the lack of information on seismic behaviour of architectural non-structural lightweight steel (LWS) drywall components, i.e. indoor partition walls, outdoor facades and suspended continuous ceilings. The tested non-structural components were made of LWS frames sheathed with gypsum-based or cement-based boards. The research activity was organized in three levels: ancilliary tests, component tests and assembly tests. Ancilliary tests were carried out for evaluating the local behaviour of partitions, facades and ceilings. Component tests involved out-of-plane quasi-static monotonic and dynamic identification tests and in-plane quasi-static reversed cyclic tests on partitions. Finally, the dynamic behaviour was investigated through shake table tests on different assemblages of partitions, facades and ceilings. The study demonstrated that the tested architectural non-structural LWS drywall components are able to exhibit a very good seismic behaviour with respect to the damage limit states according to the IDR limits given by Eurocode 8 Part 1. The current paper describes the complete experimental activity within the project.

The search for innovative methods to ensure high structural, technological and environmental performance is an important issue in the development of new constructions. Among the several available building systems, constructions involving the structural use of Cold-Formed Steel (CFS) profiles represent an efficient and reliable solution. In an effort to characterize the seismic response of CFS structures and to support the spreading of these systems, a theoretical and experimental research has been carried out at University of Naples Federico II within the Italian research project RELUIS-DPC 2010-2013. It focused on the "all steel design" solution, in which CFS diagonal strap-braced stud walls are the main lateral resisting system. In order to overcome the lack of information in the current European codes, a critical analysis of the requirements for these systems provided by the AISI S213-2007 has been carried out by comparing them with those given by Eurocodes for hot-rolled X-braced steel frames (tension-only). On the basis of the design hypothesis outlined from this analysis, a case study has been developed with the aim to define an extended experimental campaign involving 12 tests on full-scale CFS diagonal strap-braced stud walls. Finally, on the basis of experimental results, the assumed design prescriptions and requirements, such as the force modification factor and the capacity design rules, have been verified.

The seismic behavior of sheathed cold-formed steel (SCFS) structures is characterized by the lateral response of shear walls. Basically, if cold-formed steel (CFS) structures are designed according to the “sheathing-design” methodology, then the seismic behavior of shear walls is strongly influenced by the sheathing-to-frame connections response, characterized by a remarkable nonlinear response and a strong pinching of hysteresis loops. In this paper the results of an extensive parametric non linear dynamic analysis, carried out on one story buildings by means of incremental dynamic analysis (IDA), using an ad hoc model of the hysteresis response of SCFS shear walls, are presented. An extended number of wall configurations has been considered investigating several parameters such as sheathing panel typology, wall geometry, external screw spacing, seismic weight and soil type. Based on IDA results, three behavior factors have been defined, which take into account overstrength, ductility and both overstrength and ductility, respectively. Finally, a design nomograph for the seismic design of single-storey SCFS frame structures developed on the basis of non-linear dynamic analysis results is presented. This last aims to complete a proposal of a design methodology, already presented by the author in the last years.

The development of light weight steel structures in seismic area as Italy requires the upgrading of National Codes. To this end, in the last years a theoretical and experimental study was undertaken at the University of Naples within the Italian research project RELUIS-DPC 2010-2013. The study focused on "all-steel design" solutions and investigated the seismic behaviour of strap-braced stud walls. Three typical wall configurations were defined according to both elastic and dissipative design criteria for three different seismic scenarios. The lateral in-plane inelastic behaviour of these systems was evaluated by twelve tests performed on full-scale Cold-formed strap-braced stud wall specimens with dimensions 2400 x 2700 m subjected to monotonic and reversed cyclic loading protocols. The experimental campaign was completed with seventeen tests on materials, eight shear tests on elementary steel connections and twenty-eight shear tests on strap-framing connection systems. This paper provides the main outcomes of the experimental investigation. Furthermore, the design prescriptions, with particular reference to the behaviour factor and the capacity design rules for these systems, have been proved on the basis of experimental results

The use of cold-formed steel (CFS) profiles in low-rise residential buildings has increased in European construction sector. The reason of this interest is related to potentialities offered by this constructive system, which are the high structural performance, lightness, short construction time, durability and eco-efficiency. Nevertheless, the current structural codes, such as Eurocodes, do not provide enough information about the seismic design of this structural typology. In an effort to investigate the seismic response of CFS structures, a theoretical and experimental research has been carried out at University of Naples Federico II, with the main aim to support the spreading of these systems in seismic areas. This study focuses on an “all-steel design” solution in which strap-braced stud walls are the main lateral resisting system. In the present paper the outcomes of theoretical phase are shown with the aim of defining the criteria for the seismic design of such structures. In particular, a critical analysis of the requirements for CFS systems provided by the American code AISI S213 has been carried out by comparing it with those given by Eurocodes for traditional braced steel frames.

The widely recognized structural performance provided by cold-formed steel (CFS) systems together with high levels of prefabrication, safety, durability and sustainability are spreading the CFS construction systems all over the world. At the same time, the actual lack in European seismic design codes requires the development of specific design procedures for the application in seismic area. The seismic behaviour of CFS structures is characterized by the lateral response of shear walls. In particular, when the sheathing-design methodology is adopted, then the seismic behaviour is strongly influenced by the nonlinear response of sheathing-to-frame connections. In this paper a performance-based design methodology for the seismic design of sheathed CFS walls is proposed. The presented methodology is based on the results of an extensive parametric nonlinear dynamic study carried out on one story buildings by means of incremental dynamic analysis. Moreover, a multistep design procedure that allows all the main structural components to be defined in three steps is developed. In particular, a nonlinear dynamic (ND) nomograph for the assessment of the external screw spacing is presented in this work in order provide a new tool that upgrade the design procedure under investigation by the Authors in the last years. Finally the application of the proposed design methodology is verified through a case study.