A novel universal device "LINGUAL RING Ri.P.A.Ra" for TMDs and cranio-cervico-mandibular pains: preliminary results of a randomized control clinical trial

The aim of this study was to evaluate functionality and clinical application of a novel immediate device in the treatment of temporomandibular disorders (TMDs). To address the research purpose, authors developed and implemented a randomized control clinical trial

Dissipative behaviour of reinforced-earth retaining structures under severe ground motion

This paper focuses on the seismic performance of geosynthetic-reinforced retaining walls (GRWs) that several evidences have shown to be generally adequate. This can be attributed to the dissipation of energy produced by the internal plastic mechanisms activated during the seismic shaking, and to an overall ductile behaviour related to the large deformation that can be accommodated by the soil-reinforcement system. Using a number of numerical computations, this work compares the behaviour of three idealized structures that were conceived in order to have a similar seismic resistance, that however is activated through different plastic mechanisms. The analyses include numerical pseudo-static computations, carried out iteratively to failure, and time-domain nonlinear dynamic analyses, in which acceleration time-histories were applied to the bottom boundary of the same numerical models used for the pseudo-static analyses. The results of the dynamic analyses were interpreted in the light of the plastic mechanisms obtained with the pseudo-static procedure, confirming that GRWs develop local plastic mechanisms during strong motion resulting in a significant improvement of their seismic performance

Probabilistic Seismic Hazard Curves and Maps for Italian Slopes

The seismic performance of an earth slope is commonly evaluated through the permanent displacements developed at the end of an earthquake. In this paper a probabilistic approach is adopted to assess the displacement of the slope for a given hazard level using an updated database of ground motions rec-orded during the earthquakes occurred in Italy. The results are presented in terms of hazard curves, showing the annual rate of exceedance of permanent slope displacement evaluated using ground motion data provided by a standard probabilistic hazard analysis and a series of semi-empirical relationships linking the permanent displacements of slopes to one or more ground motion parame-ters. The probabilistic approach permits to take into account synthetically the characteristics of the slope through the yield seismic coefficient, the aleatory variability of the ground motions and the different subsoil classes of the record-ing stations. Finally, the procedure has been extended on a regional scale to produce seismic landslide hazard maps for Irpinia, one of the most seismically active regions in Italy. Seismic landslide hazard maps are very attractive for practitioners and government agencies for a screening level analysis to identify, monitor and minimise damages in zones that are potentially susceptible to earthquake-induced slope instability

Influence of the displacement predictive relationships on the probabilistic seismic analysis of slopes

Seismically induced landslides can often cause severe human and economic losses. Therefore, it is worth assessing the seismic performance of slopes through a reliable quantification of the permanent displacements induced by seismic loading. This paper presents a new semiempirical relationship linking the permanent earthquake-induced displacements of slopes to one or two synthetic ground motion parameters developed considering the Italian seismicity, and a comparison with existing simplified displacement models is illustrated. Once combined with a fully probabilistic approach, these relationships provide a useful tool for practicing engineers and national agencies for a preliminary estimate of the seismic performance of a slope. In this perspective, the predictive capability of different semiempirical relationships is analyzed with reference to the permanent displacements evaluated for the Italian seismicity assimilating the slope to a rigid body and adopting the Newmark integration approach. The consequences of the adoption of these relationships on the results of the probabilistic approach are illustrated in terms of displacement hazard curves and hazard maps for different slope scenarios

Evaluation of Seismic Landslide Hazard Based on a New Displacement Semi-empirical Relationship

This paper presents a new semi-empirical relationship that links the permanent earthquake-induced displacements of slopes to the synthetic ground motion parameter PGA or to the couple PGA and PGV. The displacements are evaluated under the hypothesis of a rigid sliding block performing Newmark’s integrations for all the acceleration time histories of the updated Italian seismic database. The relationship reproduces well the displacements for any values of yield seismic coefficient in the whole range of peak ground acceleration. The two parameters expression is more reliable for the study of Italian slopes under seismic loading than that based on the single PGA parameter as characterised by a lower standard deviation. The proposed relationship is also combined with a fully probabilistic approach to produce displacement hazard curves and hazard maps for different sites and regions of Italy that represent a useful tool for practicing engineers and national agencies for a preliminary estimate of the seismic performance of a slope

Impactos socio-territoriales: Puerto Iguazú y Reserva Iriapú, 600 hectáreas. Misiones, Argentina

Se presenta una revisión teórica y analítica sobre la ciudad turística de Puerto Iguazú y su área periurbana, "Reserva Iriapú Parque Nacional en Misiones Argentina. En esta área se albergan comunidades nativas de guaraníes, que han sufrido modificaciones sociales en su espacio geográfico a partir del 2003, periodo en el cual los flujos de capital internacional aumentaron y las políticas públicas turísticas se consolidaron hacia procesos de internacionalización. En este contexto, el objetivo de la presente investigación se enfoca en identificar cuáles han sido los impactos socio-territoriales en el área de amortiguación, ocasionados por la actividad turística. Para ello se analizaron una diversidad de documentos (informes, planes de desarrollo, datos estadísticos de Organismos Gubernamentales, consultoras privadas e informes académicos) así como primeros acercamientos de campo al área de estudio, lo que permitió hacer una recopilación de datos y testimonios que abonaron a la revisión teórica y analítica. Donde las conclusiones muestran que las políticas turísticas y territoriales provinciales lejos de propiciar un desarrollo justo y equilibrado para las comunidades nativas, terminan por aumentar los niveles de desigualdad social y profundizar la polarización socio-territorial, disminuyendo a la vez la participación ciudadana.Se presenta una revisión teórica y analítica sobre la ciudad turística de Puerto Iguazú y su área periurbana, "Reserva Iriapú Parque Nacional en Misiones Argentina. En esta área se albergan comunidades nativas de guaraníes, que han sufrido modificaciones sociales en su espacio geográfico a partir del 2003, periodo en el cual los flujos de capital internacional aumentaron y las políticas públicas turísticas se consolidaron hacia procesos de internacionalización. En este contexto, el objetivo de la presente investigación se enfoca en identificar cuáles han sido los impactos socio-territoriales en el área de amortiguación, ocasionados por la actividad turística. Para ello se analizaron una diversidad de documentos (informes, planes de desarrollo, datos estadísticos de Organismos Gubernamentales, consultoras privadas e informes académicos) así como primeros acercamientos de campo al área de estudio, lo que permitió hacer una recopilación de datos y testimonios que abonaron a la revisión teórica y analítica. Donde las conclusiones muestran que las políticas turísticas y territoriales provinciales lejos de propiciar un desarrollo justo y equilibrado para las comunidades nativas, terminan por aumentar los niveles de desigualdad social y profundizar la polarización socio-territorial, disminuyendo a la vez la participación ciudadana

Soil-structure interaction for the seismic design of the Messina Strait Bridge

This paper illustrates an approach to the study of the seismic soil–structure interaction that was developed at the verification stage of the design of the Messina Strait Bridge in order to validate its seismic behaviour. It consisted of a series of two-dimensional, plane strain numerical analyses on models that included, in addition to the embedded foundation elements, a simplified structural description of the bridge towers: simplified structural models were specifically designed to reproduce the first vibrations modes of the towers, that were deemed to have the most significant influence on the system's dynamic response. Non-linear dynamic analyses were carried out in the time domain, studying the effects of two different natural records, each characterised by three orthogonal components of the soil motion. In the first part of the paper, essential information is provided about the foundations layout, the main properties of the foundation soil resulting from the in situ and laboratory investigation, and the assessment of the liquefaction potential. Then, the numerical models are discussed in some detail, with an emphasis on the modelling of the soil and of the structural elements. For sake of conciseness, details are provided only for one of the two shores. The results obtained with the present approach shed some light on the complex coupling between the soil's and the structure's behaviour, evidencing the significant role that the embedded, massive foundations of the bridge play in the dynamic response of the system. The computed time-histories of the displacements of the foundation elements are used to assess the seismic performance of the bridge

Una procedura per il dimensionamento di muri in terra rinforzata soggetti ad eventi sismici intensi

In questa nota si presenta una procedura per il dimensionamento di muri in terra rinforzata mediante il metodo pseudo-statico. In essa, il coefficiente sismico k è calibrato su prefissati livelli di prestazione del muro, espressi in termini di valori limite degli spostamenti permanenti accumulati durante l’evento sismico. Un’equivalenza di upper bound tra gli spostamenti indotti da sisma e i valori di k è stata ottenuta applicando il metodo di Newmark al database di accelerogrammi italiani, aggiornato alle registrazioni del 2017, e correggendo le relazioni empiriche ottenute per tenere conto della forma dei meccanismi plastici interni alla zona rinforzata, ai quali corrisponde la massima domanda di resistenza dei rinforzi. Fissata la prestazione sismica, il muro viene quindi dimensionato per ottenere un coefficiente sismico critico associato ai meccanismi interni (kcint) inferiore a quello associato ai meccanismi esterni (kcext), così da promuovere l’attivazione di meccanismi plastici che prevedano la mobilitazione della resistenza del sistema terreno-rinforzo, dotato di rinforzi caratterizzati da adeguati livelli di duttilità

Seismic design of geosynthetic-reinforced earth retaining walls following a pseudo-static approach

Geosynthetic-reinforced earth (GRE) retaining walls show a better performance than conventionally-designed walls during destructive earthquakes, due to their capability of redistributing seismic-induced deformations within the reinforced zone. In this paper, a recently-proposed method to design GRE walls is first recalled, where the wall is designed to trigger an internal plastic mechanism in the presence of strong earthquakes. Following a pseudo-static approach, the seismic coefficient k is therefore assumed equal to the internal seismic resistance of the wall kcint. The seismic coefficient is then calibrated against given seismic wall performance, expressed in terms of limit values of earthquake-induced displacements. Permanent displacements are evaluated through empirical relationships that were previously developed on the basis of a parametric integration of an updated Italian seismic database. Effectiveness of the proposed procedure is then demonstrated by assessing, through Finite Difference nonlinear dynamic analyses, the seismic performance of two walls, namely a GRE and a conventional gravity wall, characterised by the same seismic resistance but triggering an internal and external plastic mechanism, respectively. They are both subjected to a real strong motion, capable of activating a plastic mechanism. Results showed that lower permanent displacements are accumulated in the GRE wall where internal mechanisms are triggered

Predicting the seismic behaviour of the foundations of the Messina Strait Bridge

This paper presents some of the geotechnical studies carried out for the seismic design of the one-span suspension bridge across the Messina Strait, that is to connect Sicily with mainland Italy. These studies included advanced geotechnical characterisation, through in situ and laboratory tests, estimate of site stability involving both liquefaction analysis and submerged slope stability, evaluation of soil-foundation stiffness for spectral analysis of the superstructure, 3D FE static calculations, evaluation of anchor block performance under seismic conditions, and full dynamic analyses of the soil-structure interaction. The paper summarises the main results obtained from the geotechnical characterisation of the foundation soils, reports the approach adopted for evaluating the seismic performance of the anchor blocks through a modified Newmark-type calculation, and presents the study of the soil-structure interaction carried out through a series of two-dimensional, plane strain numerical analyses. In these analyses, in addition to the embedded foundation elements, the models included a simplified structural description of the bridge towers specifically designed to reproduce their first vibrations modes, that were deemed to have the most significant influence on the system's dynamic response. The illustration is limited to the foundation systems of the bridge located on the Sicily shore