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Bucharest, Romania

The aim of the paper is to present the main results of the research regarding the dynamic characteristics and modal behavior of the Central ROMEXPO Pavilion at ambient vibrations, considering different variations of the possibilities of motion of the structure. The retained study models are only those parametric situations which may be considered, from the engineering point of view, with important risk in the dynamic evolution of the motion process under the action of a strong earthquake. For this purpose multichannel, simultaneous, digital recordings are performed on site and afterwards are processed using the basic records combination method. In order to validate the obtained results an ETABS structural model of the Pavilion is constructed and the signal is processed both in the computer program LabView as well as in DaisyLAB. Source

Vasile O.,ICECON SA | Vasile O.,Polytechnic University of Bucharest
Applied Mechanics and Materials

The results of the experimental tests, in dynamic regime, on antiseismic elastomeric devices, evidenced the fact that the internal damping represents a significant parameter tightly related to the specific shearing deformation of the elastomeric elements. Consequently, based on the final obtained results, correlation curves were raised meant to represent the variation of the equivalent critical damping ration (dynamic system of order I). © (2013) Trans Tech Publications, Switzerland. Source

Vasile O.,ICECON SA | Vasile O.,Polytechnic University of Bucharest
Applied Mechanics and Materials

The paper presents the experimental results regarding the hysteretic behavior of elastomeric systems made in conformity with the European Standards SR EN 1337-3 and SR EN 15129. It is also mentioned that the hysteretic damping was determined by experimentally raising the hysteresis loop in a low-cycle harmonic regime, with a kinematic exterior excitation defined by a harmonic displacement law. In this context, it is mentioned that the area of the hysteretic loops was determined instrumentally (in analogical representation of the signals) as well as under digital form, through a sampling of the physical signal, which allows a high precision of the determination. © (2013) Trans Tech Publications, Switzerland. Source

The paper represents a work of synthesis and research for the earthquake response of structures under various assumptions. The cases of a structure with multiple degrees of freedom, having a rigid body motion between the ground-structure interface and a random, spatial motion are presented. The earthquake induces a spatial, random motion to the ground-structure interface contact points and alternative ways and hypotheses of determining the equations of motion and their solutions are shown. New approaches are needed because the simplified manner in which this subject is usually treated (one degree of freedom or plane structures) is not compatible with the real, physical, phenomenon and may introduce coarse errors in analyses or design. When the non-synchronous nature of motion of the ground-structure interface is important, instead of dealing with the unknowns of relative displacements, absolute displacements should be considered. © 2014, Romanian Society of Acoustics. All rights reserved. Source

Romanian Journal of Acoustics and Vibration

The aim of the paper is to present the experimental results performed on two categories of concrete, C35/40 and C40/50, in order to highlight the evolution of their compressive strength with respect to the duration of vibration. The strength of the concrete made with a determined dosage greatly depends on the compaction degree. The compaction process of the fresh concrete can be optimized through an efficient correlation of the compaction degree with the vibration parameters (amplitude, frequency). © 2014, Romanian Society of Acoustics. All rights reserved. Source

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