1,721,133 research outputs found
Experimental analysis of fiber-reinforced mortar for walls in rectified brick blocks=Analisi sperimentale di malte fibrorinforzate per pareti in blocchi di laterizio rettificati
No full textThe paper examines the possibility of using the rectified bricks and in particular its installation through the innovative technique of the “thin joint”. The following experimental study was also intended to investigate the ossibility of using new mixes by adding different types of plastic fibers, mono and pluri-filament, with the aim of improving the action of sewing inside the joint, to affect the failure mechanisms and provide additional resistance to the ombination of clay-adhesive. *** Il lavoro esamina le possibilità di utilizzo del laterizio rettificato ed in particolare la sua posa in opera attraverso l’innovativa tecnica del “giunto sottile”. Con il seguente studio sperimentale si è voluto inoltre investigare la possibilità di utilizzare nuovi impasti con l’aggiunta nella matrice di differenti tipologie di fibre plastiche, mono e plurifilamento, con lo scopo di migliorare l’azione di cucitura all’interno del giunto, in modo da modificare i meccanismi di rottura e fornire resistenze aggiuntive al binomio laterizio-collant
Experimental analysis of a model isolated at the base with rubber-layer roller bearings (RLRB)
No full textCharacterization tests of new aluminium and steel energy dissipating devices
No full textIn this paper shear panels made of steel and aluminium alloy have been designed as energy dissipating devices for passive protection of structures. Preliminary tests have been performed on these panels, in order to evaluate their mechanical characteristics. Pulsating load cycles have been utilised and the corresponding displacements measured. An analytical expression of the applied shear load as function of the displacement at the end of each panel has been obtained: the resulting analytical form could be directly used for computational purposes. In addition, local strains have been measured in order to verify local plasticizations of panels and their energy dissipation capacity
"Swinging-bell resonances and their cancellation identified by dynamical testing in a modern bell tower"
No full textThe occurrence of the resonance phenomenon causes high amplitude dynamic vibrations in slender structures. This paper presents an archetypal example. including analysis and mitigating intervention, based on the real case study of a bell tower. Resonances between the multi-harmonic swinging motion of five oscillating bells and the first natural frequency of the supporting system. namely a modern tower realized in reinforced concrete, are clearly demonstrated. Using ambient vibration acceleration measurements, the modal parameters of the tower are identified consistently by two different output-only procedures: the first, based on the Complex Mode Identification Function, exploits a frequency representation of the response; the second, based on the Stochastic Subspace Identification Method, works in the time domain. The frequency characteristics of the bell-swinging action are determined through spectral analyses of the structure forced response signals, measured during the swinging motion of each bell separately. The closeness of the tower's first natural frequency with the third harmonic of the dynamic horizontal force transmitted to the structure by the two heaviest swinging bells is recognized as the source of large oscillations. A finite element model is developed and manually updated to accurately reproduce the tower's spectral properties and to design a structural intervention for the vibration mitigation. The resonance cancellation obtained through the introduction of a stiffening strut is demonstrated to limit the bell-induced oscillations effectively, as verified by a post-intervention dynamic test campaign
Dynamic identification of a modern bell tower: resonance cancellation through stiffening intervention
No full textModal parameters identification on environmental tests of an ancient tower and validation of its FE model
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Identification of the modal properties of a squat historic tower for the tuning of a FE model
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