Search results for "Forced"
showing 10 items of 500 documents
Assessment of seismic resistance of masonry structures including boundary conditions
2002
The paper is devoted to the investigation of seismic response of the masonry structure and describes experiences with modelling of boundary conditions during the test of large heavy model on 6DOF shaking table. The main aim of the research was how to increase dynamic resistance capacity of old masonry buildings including the medium and strong seismic effects. The results of theoretical and numerical analyses are compared including initial forecasting calculations made before any test started. The emphasis is given to the boundary conditions reached during the excitation of the large masonry model via shaking table. Strengthening and retrofitting procedures and their effects are discussed wh…
Simplified flexural response of steel-fiber reinforced concrete beams
2008
In the present paper, an analytical model is proposed that is able to determine the flexural response of supported beams under four-point bending tests. Cases of normal strength reinforced concrete beams with longitudinal bars in the presence of reinforcing hooked steel fibers and transverse stirrups are considered. A simplified analytical model is presented that is able to calculate the load-deflection curves and the maximum and ultimate deflections occurring in the case of shear or flexure failures. In the case of shear failure, the maximum shear strength of the beams is evaluated by using a recent analytical expression proposed by the author able to account for the shear-to-moment intera…
Generalization of Shear Truss Model to the Case of SFRC Beams with Stirrups
2012
A theoretical model for shear strength evaluation of fibrous concrete beams reinforced with stirrups is proposed. The formulation is founded on the theory of plasticity and the stress field concepts, generalizing a known plastic model for calculating the bearing capacity of reinforced concrete beams, to the case of fibrous concrete. The beneficial effect of steel fibres is estimated taking into account the residual tensile strength of fibrous concrete, by modifying an analytical constitutive law which presents a plastic plateau as a post-peak branch. Around fifty results of experimental tests carried out on steel fibrous concrete beams available in the literature were collected, and a compa…
Finite element modelling of slipage between FRP rebar and concrete in pull-out test
2014
The paper presents numerical results of direct pull-out test of glass fiber-reinforced polymer (GFRP) rebars embedded in concrete. Rebars of three different cross-sections are considered: circular without longitudinal ribs and with two and four ribs. The design analyses of the rebar configurations embedded in concrete are investigated by the 3D finite element method (FEM), which takes into account the non-linearity using ANSYS software. The results of the numerical model with two ribs were compared with the experimental results. Then, the effect of different rebar geometries to the load-slip pull-out curves was studied. It is concluded that the influence of rib height and width on the pull-…
Masonry infills and RC frames interaction: Literature overview and state of the art of macromodeling approach
2015
The issue of the influence of masonry infills within RC frames structures has been widely investigated in the last decades by several researchers. The large interest addressed to this topic depends on the actual observation that when in presence of seismic events, the response of framed structures is strongly conditioned by the interaction with the infill walls, which however are considered as non-structural elements and not included in the models. The influence of masonry infills role in structural response is so much relevant to affect not only the overall strength and the stiffness but it may also radically change the possible collapse mechanisms of the overall structural complex under t…
Flexural behaviour of external R/C steel fibre reinforced beam-column joints
2011
ABSTRACT A softened strut-and-tie macro model able to reproduce the flexural behaviour of external beam-column joint is presented. The model is specific for concrete with hooked steel fibres (FRC) and it is designed to calculate the flexural response, as load-deflection curve, of a beam-column sub-assemblages. The model considers the presence of a constant vertical load acting on the column and of a monotonically increasing lateral force applied at the tip of the beam.
Palliative Treatment of Dyspnea With Epidural Methadone in Advanced Emphysema
2005
This study investigated whether epidural methadone perfusion at the thoracic level can mitigate dyspnea in patients with advanced emphysema.Open-label clinical trial without a control group.University hospital.The inclusion criteria were a diagnosis of emphysema, basal dyspnea index (Mahler scale)or = 3, FEV(1)or = 35%, and no indication for pneumoreduction or lung transplantation surgery.An epidural catheter was inserted at the thoracic level connected to a perfusion pump for administering methadone (6 mg/24 h). Assessments were made at baseline, 1 week, and 1 month after catheter insertion.Pulmonary function tests were performed, and determinations were made of arterial blood gas levels, …
Separated Children’s Migration in the Mediterranean Sea. An Ethnohistorical Perspective
2016
In the imaginary of Italian people, the Island of Lampedusa (Italy) has always been considered a paradise destination for summer holidays. The beauty of this small island at the heart of the Mediterranean Sea, far from big harbors and cities, with its rich biodiversity and unspoilt nature, has made it a national and international tourist attraction. However, in recent years its name become associated with scenes of tragic, desperate journeys made by people of different origins trying to reach Europe from North African coasts. This shift exists not only in Italian people’s perception, but also all over the world, as the news related to Lampedusa and other Italian areas affected by this pheno…
The Event Structure of Motion Perception
2004
Motion perception on the basis of optic flow is often studied using purely perceptual response paradigms such as forced choice preferences, and using straightforward motor responses such as simple stereotypical reaction times. Here we argue for a more complex perspective that takes into account the event structure of ecological motion perception. In particular, we hope to convince the reader that the would-be perceptual response to a motion stimulus is noticeably modified be the type of response that is required from the actor. We will argue that our actions modify our perception and more precisely, that the planning component of intended actions influence processing of time critical motion…
New evidence for chunk-based models in word segmentation.
2014
International audience; : There is large evidence that infants are able to exploit statistical cues to discover the words of their language. However, how they proceed to do so is the object of enduring debates. The prevalent position is that words are extracted from the prior computation of statistics, in particular the transitional probabilities between syllables. As an alternative, chunk-based models posit that the sensitivity to statistics results from other processes, whereby many potential chunks are considered as candidate words, then selected as a function of their relevance. These two classes of models have proven to be difficult to dissociate. We propose here a procedure, which lea…