A new macromodel for the assessment of the seismic response of infilled RC frames     

Bartolomeo Pantò  Pier Paolo Rossi 《地震工程与结构动力学》2019,48(7):792-817

Numerous research studies have proved that numerical models aiming at an accurate evaluation of the seismic response of RC framed buildings cannot ignore the inelastic behaviour of infills and the interaction between infill and frame elements. To limit the high computational burden of refined non-linear finite element models, in the latest decades, many researchers have developed simplified infill models by means of single or multiple strut-elements. These models are low time-consuming and thus adequate for static and dynamic analyses of multi-storey structures. However, their simulation of the seismic response is sometimes unsatisfying, particularly in the presence of infill walls with regular or (particularly) irregular distributions of openings. This paper presents a new 2D plane macro-element, which provides a refined simulation of the non-linear cyclic response of infilled framed structures at the expense of a limited computational cost. The macro-element consists of an articulated quadrilateral panel, a single 1D diagonal link, and eight 2D links and is able to model the shear and flexural behaviour of the infill and the non-linear flexural/sliding interaction between infill and surrounding frame. The proposed macro-element has been implemented into the open source software OpenSees and used to simulate the response of single-storey, single-span RC infilled frame prototypes tested by other authors. The above prototypes are selected as made of different masonry units and characterised by full or open geometric configuration.  相似文献   

Anti-erosive effectiveness of Eucalyptus coppices through the cover management factor estimate     

Sergio Cinnirella  Francesco Iovino  Paolo Porto  Vito Ferro 《水文研究》1998,12(4):635-649

In this paper sediment yield data, measured from 1978 to 1994 in two small Calabrian basins (W2 and W3) reafforested with eucalyptus trees (Eucalyptus occidentalis Engl.), and the Modified Universal Soil Loss Equation (MUSLE) applied in a distributed form are used to evaluate the anti-erosive effects of eucalyptus cover. At first step the sediment yield measurements observed in W2 basin are used to estimate a single cover management factor representative of the eucalyptus coppice and equal to the median value (0·164) of the cover management factor values calculated for each runoff event. Then, the reliability of the selected representative cover management factor is verified on W3 by comparing the cumulative distribution function (CDF) of the measured sediment yield with the CDF of the calculated one. Finally, the temporal analysis of the crop and management factor is developed searching, at monthly and annual scale, the correlation between crop anti-erosive effectiveness and rainfall erosivity index. © 1998 John Wiley & Sons, Ltd.  相似文献   

From flood risk mapping toward reducing vulnerability: the case of Addis Ababa     

De Risi  Raffaele  Jalayer  Fatemeh  De Paola  Francesco  Carozza  Stefano  Yonas  Nebyou  Giugni  Maurizio  Gasparini  Paolo 《Natural Hazards》2020,100(1):387-415

Natural Hazards - Flood risk maps for the built environment can be obtained by integrating geo-spatial information on hazard, vulnerability and exposure. They provide precious support for strategic...  相似文献   

New coring study in Augusta Bay expands understanding of offshore tsunami deposits (Eastern Sicily,Italy)     

Alessandra Smedile  Flavia Molisso  Catherine Chagué  Marina Iorio  Paolo Marco De Martini  Stefania Pinzi  Philip E. F. Collins  Leonardo Sagnotti  Daniela Pantosti 《Sedimentology》2020,67(3):1553-1576

Tsunami deposits present an important archive for understanding tsunami histories and dynamics. Most research in this field has focused on onshore preserved remains, while the offshore deposits have received less attention. In 2009, during a coring campaign with the Italian Navy Magnaghi, four 1 m long gravity cores (MG cores) were sampled from the northern part of Augusta Bay, along a transect in 60 to 110 m water depth. These cores were taken in the same area where a core (MS06) was collected in 2007 about 2·3 km offshore Augusta at a water depth of 72 m below sea level. Core MS06 consisted of a 6·7 m long sequence that included 12 anomalous intervals interpreted as the primary effect of tsunami backwash waves in the last 4500 years. In this study, tsunami deposits were identified, based on sedimentology and displaced benthic foraminifera (as for core MS06) reinforced by X-ray fluorescence data. Two erosional surfaces (L1 and L2) were recognized coupled with grain-size increase, abundant Posidonia oceanica seagrass remains and a significant amount of Nubecularia lucifuga, an epiphytic sessile benthic foraminifera considered to be transported from the inner shelf. The occurrence of Ti/Ca and Ti/Sr increments, coinciding with peaks in organic matter (Mo incoherent/coherent) suggests terrestrial run-off coupled with an input of organic matter. The L1 and L2 horizons were attributed to two distinct historical tsunamis (ad 1542 and ad 1693) by indirect age-estimation methods using ²¹⁰Pb profiles and the comparison of Volume Magnetic Susceptibility data between MG cores and MS06 cores. One most recent bioturbated horizon (Bh), despite not matching the above listed interpretative features, recorded an important palaeoenvironmental change that may correspond to the ad 1908 tsunami. These findings reinforce the value of offshore sediment records as an underutilized resource for the identification of past tsunamis.  相似文献   

Dynamics of three-block assemblies with unilateral deformable contacts. Part 1: contact modelling     

Ugo Andreaus  Paolo Casini 《地震工程与结构动力学》1999,28(12):1621-1636

As far as the dynamics of multibody systems is concerned, a brief review has been performed in order to frame the dynamic response of a trilith (the simplest scheme of a colonnade belonging to a temple) into a wide theoretical background. Under the assumption of rigid bodies, two different approaches can be found in the literature: rigid or deformable contacts formulation. In this paper, an effort is made at outlining the principle of rigid contact formulation and of deformable contact formulation. The latter approach can be assumed within the framework of the distinct element method; for this purpose a model of deformable contact has been proposed in order to simulate the real behaviour of stone joints. The sample application referred to the trilith will be presented in Part 2. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

Vertical oscillations due to axial-bending coupling during seismic response of RC bridge piers     

Giulio Ranzo  Marco Petrangeli  Paolo Emilio Pinto 《地震工程与结构动力学》1999,28(12):1685-1704

The paper presents a numerical investigation on the behaviour of reinforced concrete bridge piers subjected to horizontal seismic input. The scope of the investigation is to quantify the phenomenon of bending-induced axial vibrations. The results of a set of analyses conducted on single-column bent systems indicate that flexural cracking produces, in fact, significant axial vibrations. This effect is particularly relevant in squat elements with low axial force where the sway of the cross-sectional neutral axis under alternate bending causes strong hammering impulses at crack closure. Quantification of the effects related to this phenomenon can be determinant for the seismic assessment of existing bridges as well as for the design of new bridges. Likewise, performance and design forces of bearings and other anti-seismic devices can be estimated with more accuracy, based on the expected level of combined vertical and horizontal acceleration response on decks. The pier overall flexural response is not significantly altered by the fluctuation in axial force associated to these impulses, although local moment–curvature behaviour is, due to axial–bending interaction. Shear resisting mechanisms should be more sensitive to these vibrations and shear failure anticipated when a reduction in the axial contribution to the section shear capacity occurs. A tentative equation for the prediction of this flexural-induced vertical acceleration component is proposed based on simplified section kinematics and elastic impact analysis. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

A map-matching algorithm dealing with sparse cellular fingerprint observations     

Andrea Dalla Torre  Paolo Gallo  Chris Marshall  Angelo Montanari  Federico Pittino 《地球空间信息科学学报》2019,22(2):89-106

ABSTRACT

The widespread availability of mobile communication makes mobile devices a resource for the collection of data about mobile infrastructures and user mobility. In these contexts, the problem of reconstructing the most likely trajectory of a device on the road network on the basis of the sequence of observed locations (map-matching problem) turns out to be particularly relevant. Different contributions have demonstrated that the reconstruction of the trajectory of a device with good accuracy is technically feasible even when only a sparse set of GNSS positions is available. In this paper, we face the problem of coping with sparse sequences of cellular fingerprints. Compared to GNSS positions, cellular fingerprints provide coarser spatial information, but they work even when a device is missing GNSS positions or is operating in an energy saving mode. We devise a new map-matching algorithm, that exploits the well-known Hidden Markov Model and Random Forests to successfully deal with noisy and sparse cellular observations. The performance of the proposed solution has been tested over a medium-sized Italian city urban environment by varying both the sampling of the observations and the density of the fingerprint map as well as by including some GPS positions into the sequence of fingerprint observations.  相似文献   

Validation of Geant4 10.3 simulation of proton interaction for space radiation effects     

Vladimir Ivanchenko  Paolo Dondero  Valentina Fioretti  Anton Ivantchenko  Fan Lei  Simone Lotti  Alfonso Mantero  Teresa Mineo 《Experimental Astronomy》2017,44(3):437-450

Monte Carlo simulation of space radiation effects induced by protons is important for design of space missions. Geant4 is a well established toolkit for Monte Carlo simulation focused on high energy physics applications. In this work, a set of new validation results versus data for Geant4 electromagnetic and hadronic interaction of protons is presented and discussed. Optimal configuration of Geant4 physics for space applications is proposed.  相似文献   

Possible stellar asterisms carved on a protohistoric stone     

Paolo Molaro  Federico Bernardini 《Astronomische Nachrichten》2023,344(10):e20220108

Chisel marks on a stone uncovered in Rupinpiccolo protohistoric hill fort from north-eastern Italy were suggested to be a representation of the night sky (Bernardini et al. 2022 Documenta Praehistorica XLIX). The patterns of the 29 marks are analyzed here to establish if they reproduce popular stellar asterisms. Nine marks are found to match the Tail of Scorpius and five the Orion's Belt, together with Rigel and Betelgeuse. Nine marks are found in the approximate position of the Pleiades showing some match with the cluster members. On the back side, 5 marks possibly reproduce Cassiopeia. One mark slightly North of Orion cannot be identified. The 28 marks show a Pearson correlation coefficient $$(28) with stellar positions higher than 0.99 with a probability $$ of a wrong correlation lower than 0.001. Departures are about one degree, or about 7 mm, as the mean diameter of the marks, which suggests a manufacturing limitation in the charting. The fort dates $$1800–400 BCE when Scorpius and Orion showed about the same orientation at the heliacal rising. The unidentified mark challenges the whole picture. We suggest it could have been the progenitor of a failed supernova, thus offering also the possibility of a verification.  相似文献