Investigating the Performance of a Degraded Prestressed Concrete Box Girder Half-joint Bridge in the Spirit of the Italian Guidelines

The paper investigates a paired pre-stressed box-girder concrete bridge, according to the framework suggested by the new Italian Guidelines for the risk assessment of existing bridges. The bridges, selected as case study within the research agreement signed by the FABRE Consortium and ANAS S.p.A. for first applications of the Italian Guidelines, present significant age-related degradation phenomena known to the Administrator, who decided for the bridges demolition and reconstruction. Visual inspections confirmed defects in the pre-stressing system, a permanent deflection of the deck, and cracks at half-joints, possibly due to pre-stressing loss and creep effects triggered by the poor quality of concrete. Also, preliminary safety verifications revealed not to meet code requirements in most cross-sections. Consequently, the most degraded bridge was closed. From March 2022, experimental campaigns have been performed by the FABRE Consortium and ANAS for improving their experience on the behaviour of old pre-stressed concrete bridges, as well as to control possible performance loss of the open bridge, sustaining the overall route traffic. The paper summarises these activities and presents some possible future investigations to be carried out before bridge demolition

CARTOGRAFIA GEOMORFOLÓGICA DETALHADA: A REPRESENTAÇÃO GRÁFICA DO RELEVO ENTRE 1950-1970

Sistemas de cartografia geomorfológica propostos por países europeus, entre eles Polônia, França e Rússia, datam dos anos 1950; os congressos da UGI balizaram a evolução da cartografia desde 1956 quando cartas geomorfológicas detalhadas foram apresentadas no Congresso Internacional de Geografia do Rio de Janeiro. Em 1960, a UGI criou, na Comissão de Geomorfologia Aplicada, a Subcomissão de Cartografia Geomorfológica que estabeleceu regras para execução das cartas e determinou a prática de levantamentos específicos para a pesquisa geomorfológica. Adotaram-se princípios uniformes para permitir comparações entre cartas e subsidiar o planejamento econômico com representações corretas do relevo. Em 1962, a Conferência Internacional da UGI na Polônia analisou mapas geomorfológicos de 14 países, mas a disparidade de conteúdos e formas de representação prejudicou comparações entre eles. Para incentivar a construção de mapas compatíveis se recomendou a realização de mapas baseados em trabalho de campo complementado com fotos aéreas, plotados em cartas topográficas detalhadas e produzidos em escalas de 1:10.000 ─ 1:100.000. A representação completa do relevo do ponto de vista da dinâmica requeria a inclusão de dados morfográficos, morfológicos, morfogenéticos e morfocronológicos e a identificação das feições por meio de signos multicoloridos. A composição da lista de formas e a escolha dos signos da legenda tiveram como base legendas existentes e/ou dados de mapas geomorfológicos de áreas com históricos geológico-ambientais diversos; a legenda deveria ser continuamente atualizada e complementada com dados de regiões diversas daquelas onde se originaram os sistemas existentes. Em 1972, Demek editou o Manual de Cartografia Geomorfológica Detalhada, que sistematiza resultados de propostas discutidas pela Subcomissão no Congresso da UGI em Nova Delhi (1968)

Il restauro della Madonna di Macerata di Carlo Crivelli. La riscoperta di un capolavoro su tela

Il restauro della Madonna con il Bambino di Carlo Crivelli, conservata nei Musei civici di palazzo Buonaccorsi a Macerata, ha portato a una delle più importanti scoperte degli ultimi anni intorno al pittore veneziano e, più in generale, al contesto artistico italiano del XV secolo. Il dipinto è giunto fino a noi attraverso incredibili vicissitudini conservative, solo in parte ricostruibili attraverso le fonti. Per oltre un secolo gli studiosi hanno dibattuto su ogni aspetto dell’opera, restando tuttavia concordi nel ritenere la tela frutto del trasporto da una tavola, probabilmente di dimensioni maggiori, tagliata e riadattata salvando le figure principali: un dipinto menomato e alterato nel suo aspetto materico e percettivo, ritenuto, dunque, secondario nel catalogo del maestro veneziano. Nel 2022 è stata presa la decisione di far restaurare la Madonna. Il complesso e delicatissimo intervento ha permesso di scoprire che l’opera, invece, fin dall'origine è stata realizzata su tela, l’unica, a nostra conoscenza, eseguita su tale supporto da Carlo Crivelli. Il dato ha rivoluzionato gli studi sul pittore veneziano, ritenuto un indiscusso maestro della pittura su tavola, aprendo quindi nuovi scenari di ricerca e suscitando un ampio dibattito fra gli specialisti e confermando, ancora una volta, l’impiego della tela quale supporto per opere a carattere devozionale anche nel XV secolo. Il libro raccoglie i risultati del restauro e delle complesse indagini diagnostiche che lo hanno accompagnato, costituendo il resoconto del consistente intervento conservativo, contestualizzato nel quadro dell'analisi storica della tela, della sua ricezione e musealizzazione.The restoration of Carlo Crivelli's Madonna and Child, preserved in the Civic Museums of Palazzo Buonaccorsi in Macerata, has led to one of the most important discoveries in recent years around the Venetian painter and, more generally, the Italian artistic context of the 15th century. The painting has come down to us through incredible conservation vicissitudes that can only be partially reconstructed through sources. For more than a century, scholars have debated every aspect of the work, nevertheless remaining in agreement that the canvas is the result of transport from a panel, probably larger in size, cut and readjusted while saving the main figures: a painting maimed and altered in its material and perceptual aspect, considered, therefore, secondary in the Venetian master's catalog. In 2022 the decision was made to have the Madonna restored. The complex and very delicate intervention made it possible to discover that the work, instead, from its origin was made on canvas, the only one, to our knowledge, executed on such a support by Carlo Crivelli. The datum revolutionized studies on the Venetian painter, considered an undisputed master of panel painting, thus opening up new research scenarios and sparking a wide debate among specialists and confirming, once again, the use of canvas as a support for works of a devotional character even in the 15th century. The book brings together the results of the restoration and the complex diagnostic investigations that accompanied it, constituting an account of the substantial conservation intervention, contextualized within the framework of the historical analysis of the canvas, its reception and musealization

Analysis of ground-transducer coupling in monitoring vibration from railways: A case study

Monitoring railway-induced ground vibrations represents a fundamental step in assessing the environmental impact of train passage on buildings and surrounding receptors. For this purpose, accurate measurements of seismic waves are often required. Nevertheless, depending on soil structure, its characteristics or surface, the placement of transducer may affect the shape and phase of the seismic wave determining signal distortion and finally affecting the measurement itself. In particular, the most critical aspect of the sampling phase is represented by the coupling between the seismic transducer and the soil. Slipping or friction of the transducer may generate unacceptable results. For this purpose, different methods of coupling were tested in different conditions with regard to high speed train passages near a location in Rome. To start the test, some steel spikes of different shapes and lengths were tested in order to investigate their response to ground characteristics, surface and resonance frequency. The sampling campaign was carried out by fastening the transducers on the spikes fixed vertically in the soil at a certain distance from the railway track. Sampled data consisting of each passage in Peak Particle Velocity and acceleration were compared with those obtained by coupling transducers as defined in UNI 9916 norms. According to this norm, sensors are buried into the soil at a fixed depth depending on their dimensions. The final part of the sampling is aimed at comparing the sets of obtained values. This analysis is focused on the identification of those parameters to be taken into account in order to select the best coupling method for different conditions

Sequential Gaussian Simulation as a tool to improve PM10 sampling scheme in industrial sites

This paper is focused on the role of spatial and variographic analysis in the phase of sampling design. In particular, when dealing with environmental variables such as airborne dust concentration all over a selected domain, the best approach to catch the spatial structure of the variable itself, implies the full and more detailed coverage of the domain. In this study this goal is achieved by means of about fifty airborne dust concentration field surveys all over a square area 350 mt wide in a quarry plant in the center of Italy. These data, sampled according with a regular pattern, did not allow to catch the spatial structure of the variable itself thus avoiding a satisfactory variographic modelling. To improve the sampling scheme an infilling procedure was performed by adding an increased number of samples. The selection of these further samples, less than 10% of the total amount, was carried out using sequential Gaussian simulations in those zones of the domain in which the highest variability was recorded. The final outcome shown a good result determining a good upgrade in terms of variographic modelling and final estimation at the cost of few further samples

Urban tram induced vibrations: Real time monitoring of historical buildings in the centre of rome

The phenomenon of the structural stress generated by vibrations caused by traffic is of concern in all urban settings. In order to characterize this phenomenon three elements must be identified: the source, the propagation mean, and the receptor. Many parameters affect this phenomenon and several models are present in the scientific literature regarding the impact analysis of tramway induced vibrations in an urban context. The aim of this paper is to study the transfer function from a source (trams) to a receptor (historic buildings) to produce a predictive model capable of estimating attenuation levels of vibration. From experimental data, obtained from a measurement campaign carried out in the historical centre of Rome, a function was obtained that allows an attenuation level to be estimated in a historical urban context. © SGEM2015