The Influence of the Aspect Ratio on the Lateral Response of the Sheathed Cold Formed Steel Walls

The influence of the aspect ratio on the lateral response of cold formed steel walls is analyzed by three design methodologies. In particular the prediction provided by the AISI Lateral Design, that is at the moment the main document for the design of CFS buildings under horizontal loads, is compared with the results obtained by applying the principles of mechanics and with those provided by non-linear finite element models. This paper presents and discusses in terms of strength and stiffness the validity of the different design methodologies in case of non-conventional wall aspect ratios comparing the numerical results with available experimental data

Seismic behaviour of “all-steel” CFS structures: Design criteria

The search for innovative building methods to ensure high structural, technological and environmental performance is promoting the development of light gauge steel structural systems. Among them, stick-built constructions realized with Cold-Formed Steel (CFS) profiles are attracting considerable interest in the construction sector and in the recent research studies. Nevertheless, the main European structural code for seismic design, the Eurocode 8 part 1 (EN 1998-1) [1], does not provide any prescription for the seismic design of CFS structures. Presently, the "North American Standard for Cold Formed Steel Framing - Lateral Design" AISI S213-07 [2] represents the only reference for the design of this structural typology under seismic actions. This document is developed by the American Iron and Steel Institute Committee on Framing Standards and it codifies the design of different seismic resistant CFS systems for Canada, Mexico and United States. As an effort to define the seismic design criteria for such structures, an extended theoretical and experimental study aimed to investigate the seismic behaviour of strap-braced stud shear walls has been carried out within RELUIS –DPC 2010-2013 research project. The research included a wide experimental campaign as well as theoretical analyses to define criteria for the seismic design of strap braced CFS structures. Among the different steel seismic-resistant systems regulated by the EN 1998-1, traditional concentrically braced frame (X diagonal) represents the closest system to the investigated one. In this paper a critical analysis of the current standards is illustrated, with particular reference to the analysis and comparison of the existing provisions for the two similar structural typologies (traditional concentrically braced frames and strap braced CFS system). Based on the results of that critical analysis, the design hypotheses for the definition of a case study have been defined. In addition, on the basis of the adopted design assumptions and the experimental results [3], guidelines for the seismic design of strap braced CFS structures are proposed

Seismic response evaluation of non-structural drywall building components: Planning of an experimental campaign

Russian post-revolutionary abbreviations in the first bilingual Russian dictionariesThe process of real expansion of abbreviations started at the end of 19th century and it developed tremendously in 20th century. The process of creating abbreviations in Russian became active after World War I and suddenly became widespread particularly in the post-revolutionary period. At that time abbreviations were created spontaneously and in a disorganized way, yet numerous creations were commonly used. The period of time during which they were used was usually short, compare: ОСОАВИАХИМ (= Общество содействия обороне, авиации и химическому строительству). In most cases they were names of political parties, combat, revolutionary, social and other organizations, for instance: волисполком, военкомат, ревком. This characteristic type of Russian lexis was very troublesome for Polish intellectuals who were trying to code the Polish Russian language, i.e. specific, language code with many Russian and Soviet idioms that was used by the Polish living in the Soviet Union during the post-revolutionary period. Attempts to standardize abbreviations were reflected in translation dictionaries (Polish-Russian and Russian-Polish) published in Moscow in the 30s of 20th century. Русские послереволюционные аббревиатуры в первых советских двуязычных словаряхПроцесс настоящей экспансии аббревиатур начался в конце XIX столетия и продолжался, продвигаясь большими темпами, в ХХ веке. В русском языке аббревиация сильно активизировалась после первой мировой войы, особенно бурно распространялась в ранний послереволюционный период. В то время аббревиатуры образовались спонтанно, стихийно, неупорядоченно, но – несмотря на это – многие подобные образования попадали в общенародный обиход. Как правило, их жизнь быстро обрывалась, ср. ОСОАВИАХИМ (= Общество содействия обороне, авиации и химическому строительству). В основном это были названия политических партий, боевых, революционных, общественных и др. организаций, напр.: волисполком, военкомат, ревком. Этот характерный слой русской лексики доставлял много хлопот польским интеллигентам, пытавшимся кодифицировать советский польский язык, этот особый, сильнорусифицированный и советизированный языковой код, используемый поляками, проживавшими в СССР в межвоенный период. Попытки нормализовать образования аббревиатурного типа нашли отражение в переводных словарях (польско-русском и русско-польском), выпущенных в Москве в 30-е годы ХХ в

Seismic behaviour of “all-steel” CFS structures: Experimental tests

The Cold-Formed Steel (CFS) structures are able to ensure a good structural response in seismic areas. Among them, the stick-built constructions raise a considerable interest in recent studies. In these structures, the lateral load bearing systems are CFS stud walls, that are generally realized with a frame in CFS profiles that can be braced by light gauge steel straps installed in an X configuration. In this case, the "all steel" design methodology can be adopted and the lateral resisting system is assured by the CFS strap-braced stud walls

Seismic Design Method for CFS Diagonal Strap-Braced Stud Walls: Experimental Validation

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

Seismic response evaluation of non-structural drywall building components: Planning of an experimental campaign

Past earthquakes have shown that the damage to non-structural elements can severely limit the functionality of most affected buildings and cause substantial economic losses. Among the non-structural building components, the ceiling-partition systems represent a large economic investment in construction sector. Nevertheless, their seismic performance is poorly understood, because information and specific guidance are very limited. In the last years, international studies have been conducted on the seismic behaviour of light gage steel stud partition walls (Lee et al. [1], Restrepo and Bersofsky [2], Tasligedik et al. [3], Retamales et al. [4], Magliulo at al. [5]), suspended ceilings (Badillo et al. [6], Magliulo et al. [7], Gilani et al. [8], Soroushian et al. [9],) and partition walls - ceiling systems (Filiatrault et al. [10], McCormick at al. [11]). Since the behaviour of these systems cannot be easily simulated with traditional structural analysis, experimentation is the main way to assess the seismic response. For these reasons, an experimental campaign has been planned at the University of Naples Federico II with the main aim to characterize the seismic response of different Cold-Formed Steel (CFS) partition drywalls and suspended continuous plasterboard ceilings. The current paper presents the research project, in terms of experimental program, prototypes and specifically designed set-up

Comportamento meccanico di giunzioni speciali per strutture di alluminio: sperimentazione e modellazione

La possibilità di ottenere attraverso il processo di estrusione profili dalla sezione personalizzata permette di concepire nuovi sistemi per il collegamento tra profili di alluminio, noti come giunzioni speciali. Infatti, è possibile ottenere sezioni dotate di scanalature e guide al cui in-terno possono disporsi organi meccanici di collegamento come viti e bulloni. Tali sistemi ri-sultano particolarmente competitivi rispetto alle soluzioni tradizionali in quanto comportano diversi vantaggi come la rapidità di esecuzione, il risparmio del materiale di base e la riduzione delle lavorazioni meccaniche. Nonostante i numerosi impieghi strutturali e il crescente interesse da parte dell'industria dell'alluminio dovuto ai vantaggi legati al loro utilizzo, le principali normative in materia non forniscono informazioni sulla progettazione di tali sistemi di giunzione. Per tale motivo, è stata pianificata una vasta campagna sperimentale finalizzata alla caratterizzare la risposta strutturale dei sistemi noti come screw-groove e bolt-channel. In aggiunta, sulla base dei risultati sperimentali sono sviluppati e calibrati modelli numerici non lineari che rappresentano uno strumento di analisi avente validità più generale

Development and Calibration of Hysteretic Model for CFS Strap braced stud walls

Cold-formed steel (CFS) members in buildings are in use for decades, but their earthquake performance remained unexplored, until recently. Eurocodes, which provide common approach for the design of buildings in Europe still lack the information on seismic design of CFS structures. However, for the last few years, University of Naples “Federico II” CFS research group is dedicated in investigating their seismic performance. One of the focus areas is characterizing seismic behaviour of CFS strap braced stud walls. This paper presents a generalized approach adopted in simulating hysteretic behaviour of these walls under cyclic load in OpenSees software. Numerical models are developed and calibrated on the basis of available experimental results