Villa P.,CNR Institute for Electromagnetic Sensing of the Environment |
Malucelli F.,Servizio Geologico |
Scalenghe R.,University of Palermo
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2014
Peri-urban areas are the extension of cities into contiguous areas, where households and farms coexist. Carbon stocks (CSs) assessment, a concept here extended to urban features, has not yet been studied in depth over peri-urban areas due to uncertainties in such CSs quantification, level of detail required about construction materials, and the high spatial variability of those stocks. Remote sensing (RS)-based techniques have been successfully utilized in urban areas for assessing phenomena such as soil sealing, sprawl patterns, and dynamics of surface imperviousness, especially focusing on land cover classification at high to medium spatial scales. Over the floodplain study area of Emilia-Romagna region (Italy), we compared mapping products derived from Landsat multiseasonal data with different CSs, in soils and impervious surfaces, such as buildings and roads. A multiscale correlation analysis and regression assessment between CSs layers and satellite products were run at different grid cell sizes (100, 250, 500, and 1000 m). Results show that RS products from processing of mid-resolution satellite data can effectively perform well enough to estimate CSs in peri-urban areas, especially at 500-1000 m scale. Urban Fraction Cover method, derived through weighting urban land cover classes (including dense, sparse, and industrial urban features) can represent a good proxy of the ratio of anthropogenic over natural CSs (R2 up to 0.75). Imperviousness Index (II) product scored high positive correlation with CSs over built-up areas (R2 up to 0.77), and strong negative correlation with organic carbon density in soil (R2 up to 0.73). © 2014 IEEE.
Bruno L.,University of Bologna |
Amorosi A.,University of Bologna |
Severi P.,Servizio Geologico |
Italian Journal of Geosciences | Year: 2015
Palaeosol-based correlations within the Late Pleistocene- Holocene alluvial succession along the Reno River, in the southern Po Plain, enabled the identification of depositional cycles falling in the sub-Milankovitch band. Each cycle, composed of overbank and fluvial facies capped by poorly to weakly developed palaeosols, is correlatable upstream to a single fluvial terrace in the Reno River valley and to an individual channel belt close to the valley outlet. Four cycles, dated to about 15-10 (c1), 10-5.5 (c2), 5.5-1.5 (c3) and <1.5 (c4) cal ky BP, respectively, were identified within the Ravenna subsynthem (AES8), an unconformity-bounded unit of the Geological Map of Italy to scale 1:50,000, corresponding to the post-Last Glacial Maximum deposits. This unit, typically wedge-shaped in coastal areas, where it consists of retrogradational (coastal plain and estuarine) deposits overlain by progradational (deltaic) facies, at the basin margin is a mud-dominated alluvial succession deposited atop laterally extensive fluvial-channel complexes. The base of AES8, correlatable to the transgressive surface identified in the coastal area, is a palaeosol dated to about 18-15 ky BP. The bounding surfaces of the high-frequency cycles are diachronous along the Reno longitudinal profile, and not necessary associated to remarkable lithological contrasts, but can be detected even in mud-dominated successions. Climate change likely exerted a major control in triggering alternating phases of river aggradation and degradation, with an increasing contribution of anthropogenic factors since the middle-late Holocene. Based on the correlation of 34 core logs and 33 well descriptions, with the aid of 71 radiocarbon dates, this study highlights to what extent palaeosols can represent powerful stratigraphic tools to identify cyclic patterns in alluvial successions, even at the millennial time scale. © Società Geologica Italiana, Roma 2015.
Milani G.,Polytechnic of Milan |
Bucchi A.,Servizio Geologico
Composite Structures | Year: 2010
Masonry curved structures, as for instance arches, domes and vaults, are very diffused in historical and existing structures and usually require seismic upgrading and/or rehabilitation. Where FRP external strips cannot be applied for some reasons, the utilization of FRP bars embedded near the external surface becomes a very interesting and effective alternative. In this paper, a kinematic Finite Element limit analysis model to predict collapse loads and failure mechanisms of masonry curved structures reinforced with near surface mounted FRP bars regularly distributed is presented. Reinforced masonry homogenized failure surfaces are obtained by means of a compatible identification procedure, where a central brick is supposed interacting with its neighbors by means of finite thickness mortar joints, filler epoxy resin and FRP rods. In the model, it is required only that the curved structure results from a periodic disposition of bricks, mortar and FRP bars. Therefore, any pattern (multi-leaf, multi-head and single leaf) may be potentially investigated with the procedure proposed. In the framework of the kinematic theorem of limit analysis, a simple constrained minimization problem is obtained on the unit cell, suitable to estimate - with a very limited computational effort - reinforced masonry homogenized failure surfaces. A FE strategy is adopted to solve the homogenization problem at a cell level, modeling joints, bricks, filler and FRP rods by means of 8-noded infinitely resistant parallelepiped elements. A possible jump of velocities is assumed at the interfaces between contiguous elements, where plastic dissipation occurs. For mortar and bricks interfaces, a frictional behavior with possible limited tensile and compressive strength is assumed, whereas for epoxy resin and FRP bars some formulas available in the literature are adopted in order to take into account in an approximate but effective way, the delamination of the bar from the epoxy and the failure of the filler at the interface with the joint. In order to validate the model proposed, two numerical examples are analyzed, consisting of a circular masonry arch and a hemispherical dome. For both the examples presented, comparisons with experimental evidences, where available, and alternative non-linear FE procedures are reported. Reliable predictions of collapse loads and failure mechanisms are obtained with the model proposed for all the cases analyzed, meaning that the approach may be used by practitioners for a fast and reliable evaluation of the effectiveness of a strengthening intervention. © 2010 Elsevier Ltd.
Lanzo G.,University of Rome La Sapienza |
Silvestri F.,University of Naples Federico II |
Costanzo A.,University of Calabria |
d'Onofrio A.,University of Naples Federico II |
And 4 more authors.
Bulletin of Earthquake Engineering | Year: 2011
Following the April 6th, 2009 Abruzzo mainshock, the Italian Civil Protection Department promoted a multidisciplinary study aimed at developing seismic microzonation maps for post-earthquake reconstruction planning. In the framework of this project, a Working Group, including the authors, was assembled to carry out a microzonation study on six villages located in the Middle Aterno valley. This paper focuses on the villages of Castelnuovo and Poggio Picenze, which experienced MCS intensity values of IX-X and VIII-IX, respectively. 1D and 2D linear equivalent site response analyses were carried out on representative geological cross-sections through the damaged centres and the expansion zones. The subsoil models resulting from geological, geotechnical and geophysical investigations were calibrated by comparing numerical amplification functions, in the linear range, with horizontal-to-vertical spectral ratio derived from both aftershocks and noise recordings. The input motions adopted for the analyses were five artificial accelerograms compatible with three response spectra obtained from the Italian seismic code, as well as from ad hoc probabilistic and deterministic studies. The results were expressed in the form of horizontal profiles of amplification factors in terms of peak ground acceleration, FPGA, as well as of the Housner intensity, FH, in two different range of periods; this latter parameter was shown to be almost independent of the input motion and allowed to express the dependency of site amplification on the frequency range. The amplification factors computed along the representative geological sections were finally extended with a rational procedure to the surrounding areas to draw Grade-3 microzonation maps. © 2011 Springer Science+Business Media B.V.
Interpreting the deformation phenomena triggered by the 2012 Emilia seismic sequence on the Canale Diversivo di Burana banks [Analisi dei fenomeni deformativi indotti dalla sequenza sismica emiliana del 2012 su un tratto di argine del Canale Diversivo di Burana (FE)]
Tonni L.,University of Bologna |
Gottardi G.,University of Bologna |
Amoroso S.,I.N.G.V. |
Bardotti R.,University of Florence |
And 19 more authors.
Rivista Italiana di Geotecnica | Year: 2015
The seismic sequence that in May 2012 struck a large area of the river Po Valley (Emilia-Romagna region, Northern Italy) triggered significant fractures and deformations in a number of riverbanks located close to the earthquake epicenter. Among them, one of the most severely damaged structures turned out to be the banks of an irrigation canal known as Canale Diversivo di Burana, flowing through the small village of Scortichino (Municipality of Bondeno), near the historic town of Ferrara. Large, longitudinally-oriented ground cracks were observed along a 3 km bank stretch, causing in turn severe structural damages to a large part of the approximately one hundred houses and productive activities built on the bank crown. In order to interpret the response of such soil structure during the 2012 earthquake by identifying possible damage causes as well as to suggest relevant remedial measures and seismic risk mitigation actions towards possible future earthquakes, the Emilia-Romagna regional authority launched an in-depth study carried out by a number of research groups from various Italian universities in cooperation with technical experts of the Geological, Seismic and Soil Survey Regional Department. To this purpose, a number of geotechnical investigations were performed (in situ and laboratory tests) and an accurate geotechnical model for the seismic stability analyses was thus defined. Potential liquefaction phenomena of the shallow sandy soils, in the foundation subsoil, were taken into account in the analyses. The paper describes the main features of the extensive study carried out by the working group and summarizes the most significant achievements of the analyses. © 2015, Patron Editore S.r.l. All rights reserved.