1,721,094 research outputs found
A proposal for the design of seismic resistant precast concrete industrial buildings through application of energy dissipaters in the cladding walls
No full textLo scopo di questo lavoro è quello di mostrare un approccio per la progettazione di edifici nuovi o per il recupero di edifici esistenti in prefabbricato pesante. Questa tipologia strutturale è stata fortemente colpita nei recenti eventi sismici, evidenziando le problematiche di connessione che sussistono fra le pannellature esterne di chiusura e la parte intelaiata dell'edificio. La tecnica proposta è quella di collegare rigidamente le intelaiature ai pannelli, creando un sistema accoppiato in cui sia le colonne che i pannelli contribuiscono in termini di rigidezza, resistenza e dissipazione. Al fine di conferire alle chiusure esterne un'adeguata duttilità, riducendo nel contempo la domanda sismica, si propone di inserire al piede dei pannelli dei particolari dissipatori isteretici metallici ideati dagli stessi autori. La metodologia proposta viene validata mediante l'esecuzione di alcune analisi preliminari su archetipi strutturali. I risultati mostrano l'aumento della rigidezza, con un beneficio dal punto di vista degli stati limite di servizio, ed una migliore risposta sismica, dovuta essenzialmente alla capacità dissipativa dei dissipatori aggiuntivi.The aim of this work is to show an approach for both the retrofit of existing and the design of new industrial precast concrete buildings. This typology has been strongly hit in recent seismic events showing the inappropriate detailing of the typical claddings' connections. The proposal made in this paper is to connect rigidly the panels to the internal framing creating a dual system where columns and claddings both contribute in terms of stiffness, resistance and energy dissipation. In order to provide an adequate ductility to the panels and to reduce the seismic demand, the inclusion of hysteretic dampers at the lower corners of the external walls is proposed. The methodology is validated in the paper through preliminary pushover analyses of an archetype building. The results show that considering the participation of the panels, the structure becomes stiffer, with a consequent benefit in terms of reduction of the lateral drifts, and its seismic response is improved, thanks to the high energy dissipation provided by the dampers placed at the base of the walls
Numerical study on the resistance of thread-fixed one-side bolts: Tensile and bearing strength
No full textIn steel structures, owing to technological aspects, frequently bolting access is difficult. To overcome these issues, technological research has proposed in the last decades several blind bolt systems that allow the installation of a bolt working only on one side of the connection. The simplest type of blind bolt is the thread-fixed one side bolt (TFOSBs), in which the connecting elements are fastened through threaded holes, and the connection is assured by the contact between bolt and hole threads. This type of bolting system is very easy to apply, but, currently, there are only a few design rules available. While the mechanical behaviour of TFOSBs is conceptually easy to understand, there are still some specificities that need to be accounted for and deserve specific investigations. A first aspect regards the behaviour in tension that must be characterized properly because it depends on some local effects such as the threads’ bending both bolt and hole. Similarly, regarding the behaviour in shear, due to the lack of confinement in the nut area, as already shown for similar bolt typologies, the bearing resistance may be lower compared to standard assemblies. To provide design rules for the behaviour of TFOSBs in tension and shear, in this paper, FE models and parametric studies are developed. The collected data are used to provide a prediction of the resistance of these fasteners, suggesting design rules of immediate applicability developed along the same lines of Eurocode 3 part 1.8 provisions. The results obtained suggest that, compared to standard bolt assemblies, an average reduction of 15% of the bearing resistance should be considered for the design of TFOSBs. Instead, for what regards the behaviour in tension, the shank necking failure of the bolt be achieved only by assuring minimum bolt screwing depths, which are suggested in this paper, confirming similar proposals already available in technical literature. Conversely, provided that the failure of the hole's threads is accepted a reduction coefficient of the tensile resistance to be used in design, ranging from 0 to 1, has been proposed based on the FE studies’ results
Numerical Simulation of Aluminium Stocky Hollow Members Under Uniform Compression.
No full text5th International Colloquium on Stability and Ductility of Steel Structures, Nagoya, July 29-31, 199
Experimental Analysis of Aluminium Alloy Channels Subjected to Local Buckling under Uniform Compression
No full textExperimental and numerical analyses of steel-concrete composite floors
No full textBackground: The performances of composite steel-concrete slabs are strongly influenced by the connection between the concrete and the steel decking, which is essentially assured by bonding, interlocking, and adhesion. The connection can be continuous or localized by means of connectors. In order to increase the bonding between steel and concrete elements and to allow their collaboration, typically, a continuous connection with indentations or embossings is realized. Objective: In this study, the simulation of the concrete-steel bond interaction of a typical composite decking is analyzed. In particular, the objective is the investigation of the role of the main geometric parameters of the indentations or embossings that determine the effective functionality of the connection. Methods: To this scope, the results of four-point bending tests on five specimens of a typical layout of a composite floor are reported and discussed. Then, the obtained results are used to determine the shear bond strength according to the partial interaction method, by following the procedure provided by the Eurocode 4. Successively, the experimental results are exploited in order to calibrate a FE model in Abaqus software to be able to account for the basic effects involved in the shear bonding mechanism, i.e. interlocking, friction, and adhesion. Results & Conclusion: Finally, the obtained results are discussed, and the FE model is used to evaluate the geometrical and mechanical parameters influencing the longitudinal shear bonding resistance
Local buckling of aluminium alloy angles under uniform compression: experimental analysis
No full textC. T. A. “Giornate Italiane della Costruzione in Acciaio”, Genova: 28 Settembre – 1 Ottobre 200
Influence of random material variability on the moment capacity of beam-to-column joints.
No full textChord failure resistance of 3D cut welded connections with CHS columns and through I-BEAMS
No full textPrototype Test of Resilient Friction Materials for Seismic Dampers
No full textIn recent decades, low-yielding seismic devices based on the use of friction dampers have emerged as an excellent solution for the development of building structures with improved reparability and resilience. Achieving an optimal design for such low-yielding seismic devices requires precise control of bolt preloading levels and predictability of the friction coefficient (CoF) between the damper interfaces. While various types of friction devices exist that are capable of providing significant energy dissipation, ongoing research is focused on the development of novel friction materials that exhibit a stable hysteretic response, high CoF values, minimal differences between static and dynamic CoF, and predictable slip resistance. In this context, an experimental campaign was conducted at the STRENGTH Laboratory of the University of Salerno to evaluate the behaviour of new friction shims employing specially developed metal alloys. Specifically, the influence of the characteristics of the contact surfaces in the sliding area on the behaviour and performance of the friction device was analysed. The tests followed the loading protocol recommended by EN12159 for seismic device qualification. Monitored parameters included preloading force values and the evolution of slip resistance. The friction value was determined, along with its degradation over time. Finally, the material’s performance in terms of hysteretic behaviour was assessed, providing a comparison of the tested specimens in terms of slip force degradation and energy dissipation capacity
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