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2014 Conference article Unknown
Structural analysis of the Dome of San Cerbone Cathedral in Massa Marittima (Italy)
Angelini G., De Falco A., Pellegrini D.
In this paper the assessment of the dome of the medieval cathedral of Massa Marittima (Italy) is carried out in order to evaluate the causes of its heavy damage. The deformation and the crack patterns on the vault and on the surface of the masonry drum are particularly complex and seem at first glance incomprehensible. In the context of the safety assessment of ancient masonry constructions, structural modeling can provide an important contribution to diagnose the damage while representing at the same time a valuable instrument to predict the effectiveness of consolidation interventions. This paper shows how the finite element numerical approach can be successfully employed as an assessment tool, provided that it is driven by the empirical intuitive method based on kinematic evaluations. The analysis has been conducted via the NOSA-ITACA code, developed in the framework of the project "NOSA-ITACA - Tools for modelling and assessing the structural behavior of ancient constructions" (2011-2013) promoted by the Tuscany Region (Italy). The code models masonry as a nonlinear elastic material, known as masonry-like (or no-tension) material, and is a code suitable to assess the structural behavior of masonry constructions. Initially, the different structural elements composing the dome were investigated to analyze their specific role and their typical pathology. The structure safety factor was successfully evaluated thanks to a detailed three-dimensional model of the dome with its substructure. Once validated the model in the light of the surveyed crack patterns, was also employed to design adequate strengthening interventions. For the sake of comparison, a commercial code was also used to perform the same analysis with a different constitutive equation for material thus offering the opportunity to highlight the peculiarity of NOSA-ITACA code.Source: SAHC 2014 - 9th International Conference on Structural Analysis of Historical Constructions, Mexico City, 14-17 October 2014

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2014 Conference article Unknown
Studio della cupola del Duomo di Massa Marittima
Angelini G., De Falco A., Lucchesi M., Pellegrini D.
In the context of the safety assessment of ancient masonry constructions, the structural modeling can provide an important contribution to the diagnosis of the damage, as well as an instrument for the prediction of the effectiveness of consolidation and restoration interventions. In this paper the structural analysis of the dome of the medieval cathedral of Massa Marittima is presented in order to investigate the cause of a crack pattern which seems incomprehensible at first glance. The analysis has been conducted via the NOSA-ITACA code, developed in the framework of the project "NOSA-ITACA - Tools for modeling and assessing the structural behaviour of ancient constructions" (2011-2013), funded by the Region of Tuscany. The masonry has been modeled as a nonlinear elastic material, known as masonry-like (or no-tension) material. The assessment of the structure safety factor has been performed thanks to a detailed threedimensional model that, once calibrated in the light of the surveyed crack patterns, has also been employed for the design of appropriate reinforcement interventions.Source: SAFE MONUMENTS - Conservation vs Safety of Monumental Historical Constructions = Tra Conservazione e Sicurezza di Edifici Monumentali e Costruito Storico, pp. 97–108, Firenze, Italy, 28 marzo 2014

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2015 Journal article Open Access OPEN
Fatigue behavior of stiffener to cross beam joints in orthotropic steel decks
Croce P., Pellegrini D.
In the paper the possibility to evaluate the fatigue strength of stiffener to cross beam joints in orthotropic steel decks is discussed. The proposed methodology, based on Paris-Erdogan law, allows to derive a sound estimate of the stress intensity factor K combining the indirect approach, based on the Rice J-integral, with the direct one, based on the extrapolation of experimental or numerical data. The practical implementation of the proposed methodology allowed to predict correctly the actual fatigue life of a previously tested real scale specimen, so validating its potentialities.Source: Procedia engineering 101 (2015): 101–108. doi:10.1016/j.proeng.2015.02.014
DOI: 10.1016/j.proeng.2015.02.014
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See at: Procedia Engineering Open Access | ISTI Repository Open Access | www.sciencedirect.com Open Access | CNR ExploRA


2014 Contribution to book Unknown
Chapter 4: Fatigue
Croce P., Beconcini M. L., Pellegrini D., Tanner P.
Fatigue is one the most relevant cause of failure of infrastructures or part of them, like bridges, cranes and machinery, offshore structures and so on. A lot of existing structures, mainly built before the 1980, have been designed using inappropriate fatigue classification of details or underestimating the aggressiveness of actual load spectra, so that they are subject to high fatigue failure risk, as demonstrated by fatigue cracks detected even recently in several structures. Fatigue assessment and evaluation of residual fatigue life is then a key topic in verification of existing infrastructure, also in view of designing repair interventions of fatigue damaged details and planning of future maintenance and inspection programmes.Source: Methods for the Risk Assessment and Risk - Based Management of Aging Infrastructure, edited by Milan Holick ý, Dimitris Diamantidis, pp. 81–90, 2014

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2015 Software Unknown
TruDI - A Matlab toolbox for structural dynamic identification
Pellegrini D.
TruDI (sTructural Dynamic Identification) is a Matlab toolbox for structural dynamic identification developed within the framework of the MONSTER Project (Structural Monitoring of Heritage Buildings by Wireless Technologies and Innovative Computing Tools, 2014-2016). TruDI implements the Enhanced Frequency Domain Decomposition (EFDD), a widely spread non-parametric technique for operational modal analysis developed by Batel. TruDI allows to calculate the natural frequencies, damping ratios, mode shapes and damped frequencies of a structure as well as the MPC (Modal Phase Collinearity) for each mode.

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2016 Contribution to conference Open Access OPEN
Monitoraggio dinamico e modellazione strutturale di edifici storici nel territorio lucchese: il progetto MONSTER
Pellegrini D.
Dynamic monitoring and structural modelling of historic buildings in the territory of Lucca: the MONSTER projectSource: BRIGHT Toscana 2016 - La notte dei ricercatori, Lucca, Italy, 30 settembre 2016

See at: ISTI Repository Open Access | CNR ExploRA


2019 Report Unknown
TruDI software, version 2.0 - A Matlab code for structural dynamic identification
Pellegrini D.
This technical report describes TruDI 2.0 (sTructural Dynamic Identification), a Matlab code for structural dynamic identification. TruDI 2.0 is an updated version of TruDI 1.0 and it implements the Enhanced Frequency Domain Decomposition (EFDD), a widely spread non-parametric technique for operational modal analysis and the Complex Mode Indication Function (CMIF) for experimental modal analysis. TruDI allows for calculating the natural frequencies, damping ratios, mode shapes and damped frequencies of a structure, as well as the MPC (Modal Phase Collinearity), MP (Mean Phase) and MPD (Mean Phase Deviation) for each mode.Source: ISTI Technical reports, 2019

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2021 Report Open Access OPEN
Tracking the variation of complex mode shapes for damage quantification and localization in structural systems
Masciotta M. G., Pellegrini D.
Real structures' mode shapes estimated by modal analysis techniques have a common feature: in most cases they are complex, and this complexity can derive from nonproportional damping, nonlinearities, mass loading effects, high modal density and localized damage, among others. Starting from the contributions available in the literature, the present paper investigates, from a numerical and experimental point of view, the correlation existing between localized damage and variation of global modal complexity indices conventionally employed to quantify the nonproportionality of damping in structural systems. Finally, driven by the inferences made through numerical and experimental test cases by tracking the variation of complex modes over multiple and progressive damage scenarios, a new index for damage localization and quantification is formulated and validated against real data.Source: ISTI Research reports, 2021

See at: hal.archives-ouvertes.fr Open Access | ISTI Repository Open Access | CNR ExploRA


2023 Conference article Closed Access
Assessment of the acceleration floor spectra through dynamic identification: the Museum of Bargello in Florence
Azzara R. M., Pellegrini D., Cardinali V., Viti S., Tanganelli M.
Artworks represent a priceless asset to the economic and cultural features of communities. Most art collections are hosted in Museums, which can be new buildings, appositely made for an expositive purpose, or monumental buildings, whose high artistic and historical value enhances the exposed art pieces. In this latter case, however, the Museums can disregard the seismic safety requirements provided for new constructions, becoming the main source of hazard for the precious contents they should preserve. In this paper, the dynamic behavior of the National Museum of Bargello in Florence is studied by means of a dynamic identification, focusing the attention on the "Sala di Donatello". An experimental campaign was performed by simultaneously installing two sets of three seismometric stations in the mentioned room and inside the corresponding one at the base of the building ("Sala Michelangelo"). Analysis of the recorded data via Operational Modal Analysis techniques has furnished the structure's natural frequencies, damping ratio and mode shapes allowing the assessment of the amplification of the seismic acceleration experienced by the art works exposed in "Sala di Donatello". The effect of the seismic acceleration on the artifacts has been checked on a case-study, i.e. the masterpiece "Marzocco". It is the statue of the lion considered the symbol of Florence, realized by Donatello in 1420, placed on a marble pedestal made by Benedetto da Maiano in 1480, which is a work of art as well. The assessment has been made by performing a simplified rigid-block analysis. The geometrical data of Marzocco has been stated based on a detailed photogrammetric survey, which provided a reliable representation of the mass distribution.Source: WCSI 2023 - 17th World Conference on Seismic Isolation, Torino, Italy, 12-16/09/2022
DOI: 10.1007/978-3-031-21187-4_88
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See at: link.springer.com Restricted | CNR ExploRA


2023 Report Open Access OPEN
Pre and post-diction simulation of the seismic response of a masonry cross vault tested on a shaking table
Pellegrini D.
Masonry vaults are widely employed in ancient constructions and play a crucial role in their static and dynamic behaviour. In the last decades, the scientific community has carried out, on the one hand, several experimental campaigns aimed at characterising the response of masonry vaults to horizontal actions; on the other, it has developed sophisticated numerical models able to catch the crucial features of their structural response. Within the framework of the SERA.TA project (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe), pre and post-diction contests have been organised to assess the capability of numerical methods to predict the seismic response of a 1:1 scale model of a masonry cross vault, realised and tested at LNEC laboratory (Portugal). This paper outlines the numerical analyses performed on some vault models within the pre and post-diction phase of the project. The numerical models have been created and analysed with NOSA-ITACA, a finite element software implemented at ISTI-CNR and devoted to the structural analysis of ancient masonry constructions. Pros and cons of the numerical simulations have been analysed, comparing the prediction and post-diction results with the experimental data in terms of accelerations, displacements, and crack patterns. Numerical results fit the experimental outcomes, and betterment is evident in the post-diction phase.Source: ISTI Research reports, 2023

See at: ISTI Repository Open Access | CNR ExploRA


2023 Conference article Open Access OPEN
Numerical pre-diction of the seismic behaviour of a masonry vault mock-up using the NOSA-ITACA code
Pellegrini D.
Masonry vaults are widely employed in ancient constructions and play a crucial role in their static and dynamic response. Even if they are designed to withstand gravity and dead loads, these structural elements must also resist dynamic excitations caused by traffic and earthquakes; hence, the knowledge of their behaviour still requires in-depth analyses from experimental and numerical points of view. Within the framework of the SERA.TA project (Seismolo-gy and Earthquake Engineering Research Infrastructure Alliance for Europe), a blind pre-diction contest has been organized to assess the numerical analyses capability to predict the seismic response of a 1:1 scale model of masonry cross vault, realized and tested at LNEC laboratory (Portugal). This paper describes the analyses conducted on a numerical model of the vault created by NOSA-ITACA, a code developed in-house by ISTI-CNR for the analysis and calibration of masonry structures. The experimental accelerations, displacements, and crack patterns have been compared with the predicted numerical ones achieved in the blind pre-diction phase, by performing a nonlinear dynamic analysis of the un-strengthened finite element model of the vaultSource: COMPDYN 2023 - 9th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering, Athens, Greece, 12-14/06/2023

See at: 2023.compdyn.org Open Access | ISTI Repository Open Access | CNR ExploRA


2023 Journal article Open Access OPEN
Pre- and post-diction simulation of the seismic response of a masonry cross vault tested on a shaking table
Pellegrini D.
Masonry vaults are widely employed in ancient constructions and play a crucial role in their static and dynamic behaviour. In the last decades, the scientific community has carried out, on the one hand, several experimental campaigns aimed at characterising the response of masonry vaults to horizontal actions; on the other, it has developed sophisticated numerical models able to catch the crucial features of their structural response. Within the framework of the SERA.TA project (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe), pre and post-diction contests have been organised to assess the capability of numerical methods to predict the seismic response of a 1:1 scale model of a masonry cross vault, realised and tested at LNEC laboratory (Portugal). This paper outlines the numerical analyses performed on two vault models within the pre and post-diction phase of the project. The numerical models have been created and analysed with NOSA-ITACA, a finite element software implemented at ISTI-CNR and devoted to the structural analysis of ancient masonry constructions. Pros and cons of the numerical simulations have been analysed, comparing the prediction and post-diction results with the experimental data in terms of accelerations, displacements, and crack patterns. Numerical results fit the experimental outcomes, and betterment is evident in the post-diction phaseSource: International journal of architectural heritage (Online) (2023). doi:10.1080/15583058.2023.2242812
DOI: 10.1080/15583058.2023.2242812
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See at: ISTI Repository Open Access | www.tandfonline.com Restricted | CNR ExploRA


2014 Conference article Open Access OPEN
Nonlinear analyses of the medieval "Ponte del Diavolo", Borgo a Mozzano, Italy
De Falco A., Girardi M., Pellegrini D.
Structural analyses are particularly difficult to conduct on masonry constructions as a result of the lack of knowledge of the material mechanical properties. However, one well-established peculiar characteristic of masonry is its radically different behavior under tensile and compressive stresses. A suitable constitutive equation has been developed that models masonry as an isotropic elastic non-linear material with zero tensile strength and either infinite or bounded compressive strength. This constitutive equation, which is known as the masonry-like model, has been implemented in the finite element code NOSA-ITACA, which has been successfully applied to the static analysis of several historical masonry buildings as well as the dynamic analysis of masonry pillars, beams and towers. In the work, described in this paper, the Maddalena bridge, known as the "Devil's Bridge" ("Ponte del Diavolo"), on the Serchio river in Borgo a Mozzano, Italy is studied. The paper presents several structural analyses performed using the NOSAITACA code by means of finite element models composed of plane or threedimensional elements. Initially, the structural behavior of the bridge under permanent loads is investigated using non-linear static analysis. Then, a non-linear dynamic analysis is performed using a time-dependent three-dimensional acceleration recorded during the earthquake that occurred in the nearby "Lunigiana" area on the 21 June in 2013. The results are analyzed and the differences between the linear and nonlinear behavior are highlighted.Source: CST2014 - Twelfth International Conference on Computational Structures Technology, Naples, Italy, 2-5 September 2014

See at: ISTI Repository Open Access | www.ctresources.info Restricted | CNR ExploRA


2015 Report Unknown
Train-induced vibrations on the Maddalena Bridge in Borgo a Mozzano (Italy)
De Falco A., Galletto A., Girardi M., Pellegrini D.
This paper deals with the Maddalena Bridge, also known as the "Devil's Bridge", in Borgo a Mozzano (Italy). This particularly fascinating structure was built in the 11th century as a strategic infrastructure for trade routes. Due to the changing needs and new lifestyles of modern society, its importance as a thoroughfare has been progressively lost over the centuries. The construction of a new railroad line in the early 20th century called for demolition of the bridge's right shoulder in order to build the railway embankment and a new arch for the passage of trains. Nowadays, the vibrations of passing convoys are transmitted to the bridge, and current conservation requirements for this national monument require assessments of the interaction effects with the railway infrastructure. This document reports on a vibration measurements campaign aimed at evaluating the effects of train transit in terms of stresses and accelerations on the bridge structure. To this purpose, many acceleration time-histories have been acquired on the railway and bridge both under ambient vibrations and during the passage of convoys. The analysis of the experimental data has also enabled calibration of a finite element model of the bridge. Furthermore, in order to assess the overall stress field in the structure and its dynamic behaviour, several structural analyses have been performed by modelling masonry as a nonlinear elastic material, with zero tensile strength and infinite compressive strength, according to the masonry-like model. In particular, the accelerations recorded on the railway during the transit of a cargo train have been applied to the finite-element model. Dynamic analysis was then performed and the results compared with those actually recorded on the bridge. All analyses have been performed by means of the NOSA-ITACA code (http://www.nosaitaca.it/en), in which the masonry-like model has been implemented. This study provides information on both the dynamic response of the structure and the effects produced by the passage of trains on the adjacent railway tracks.Source: ISTI Technical reports, 2015

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2015 Contribution to conference Open Access OPEN
Il progetto MONSTER: monitoraggio strutturale di edifici storici con tecnologie wireless e strumenti di calcolo innovativi
Cassarà P., Pellegrini D.
MONSTER - Structural health monitoring of historic buildings via wireless sensor networks and numerical tools The project aims at developing an integrated monitoring and simulation framework for the structural health control of ancient masonry constructions. Sensing will be based on small, inexpensive and interconnected wireless devices, developed by the Wireless Network Lab of ISTI-CNR. The data produced become the input for numerical simulations based on the NOSA-ITACA code, a finite-element software developed by the Mechanics of Materials and Structures Lab of ISTI-CNR to simulate the static and dynamic behaviour of masonry buildings, while taking into account the effects of cracking. The project's activities include some laboratory tests on the prototypes and the installation of a wireless accelerometer network on a monument in Lucca.Source: BRIGHT 2015 - BRIGHT Toscana 2015 - La notte dei ricercatori, Pisa, Italy, 25 settembre 2015

See at: ISTI Repository Open Access | CNR ExploRA


2016 Conference article Unknown
Measurement of the vibration response of the medieval Maddalena Bridge (Italy).
Azzara R. M., De Falco A., Girardi M., Pellegrini D.
Nowadays the structural health monitoring of ancient masonry constructions is a key issue. In this context, one very important approach is the use of wholly nondestructive techniques, such as measurement of the environmental vibrations affecting structures. This paper reports on a vibration measurements campaign performed on the medieval Maddalena Bridge in Borgo a Mozzano, near Lucca, also known as "Ponte del Diavolo" (Devil's Bridge), one of the most fascinating old masonry bridges in Italy. The bridge, built in the 11th century, crosses the Serchio River for about one hundred meters with four circular arcades. The monitoring system has been mainly aimed at evaluating the dynamic response of the bridge to vibrations originating in the adjacent railway and two nearby roads. Analysis of the recorded data via Operational Modal Analysis techniques has furnished the natural frequencies and mode shapes of the structure and the corresponding damping ratios.Source: 10th International Conference on Structural Analysis of Historical Constructions - Anamnesis, diagnosis, therapy, controls, pp. 631–638, Leuven, Belgium, 13-15 September 2016

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2017 Journal article Open Access OPEN
Ambient vibration recording on the Maddalena Bridge in Borgo a Mozzano (Italy): data analysis
Azzara R. M., De Falco A., Girardi M., Pellegrini D.
This paper reports on a vibration measurements campaign performed on the medieval Maddalena Bridge, also known as the "Devil's Bridge", in Borgo a Mozzano (Italy), one of the most fascinating in Italy. This 11th century masonry bridge, supported by four circular arcades, crosses the Serchio River for about one hundred meters. Information on the dynamic response of the structure have been obtained through a wholly nondestructive technique, by measuring the environmental vibrations affecting the structures. A monitoring system has been fitted on the external surface of the bridge in order to evaluate its dynamic response to vibrations originating in the adjacent railway and two nearby roads. The natural frequencies and mode shapes of the structure and the corresponding damping ratios have been obtained by analyzing the recorded data using different techniques of Operational Modal Analysis. Lastly, a finite-element model of the bridge has been calibrated to fit the experimental data.Source: Annals of geophysics (Online) 60 (2017). doi:10.4401/ag-7159
DOI: 10.4401/ag-7159
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See at: Annals of Geophysics Open Access | ISTI Repository Open Access | Annals of Geophysics Open Access | Annals of Geophysics Open Access | CNR ExploRA


2020 Contribution to journal Open Access OPEN
Editorial: urban vibrations and their effects upon built heritage: measurements, characterization, and simulations
Palermo M., Baraccani S., Girardi M., Pellegrini D., Azzara R. M.
Source: Frontiers in built environment Online 6 (2020). doi:10.3389/fbuil.2020.588758
DOI: 10.3389/fbuil.2020.588758
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See at: Frontiers in Built Environment Open Access | ISTI Repository Open Access | Frontiers in Built Environment Open Access | www.frontiersin.org Open Access | Frontiers in Built Environment Open Access | CNR ExploRA


2022 Journal article Open Access OPEN
Tracking the variation of complex mode shapes for damage quantification and localization in structural systems
Masciotta M. G., Pellegrini D.
Real structures mode shapes estimated by modal analysis techniques have a common feature: in most cases they are complex, and their level of complexity can be soundly influenced by the presence and extent of physical damage, which also affects the distribution of energy dissipation mechanisms within the structures. Starting from the contributions available in the literature, the present paper investigates, from a numerical and experimental point of view, the correlation existing between localized damage and variation of global modal complexity indices conventionally employed to quantify the nonproportionality of damping in structural systems. Finally, driven by the inferences made through numerical and experimental test cases by tracking the variation of complex modes over multiple and progressive damage scenarios, a new index for damage localization and quantification is formulated and validated against real data.Source: Mechanical systems and signal processing 169 (2022). doi:10.1016/j.ymssp.2021.108731
DOI: 10.1016/j.ymssp.2021.108731
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See at: ISTI Repository Open Access | www.sciencedirect.com Restricted | CNR ExploRA


2014 Contribution to conference Open Access OPEN
Safety assessment of masonry constructions via numerical tools: the NOSA-ITACA code
Binante V., Girardi M., Lucchesi M., Padovani C., Pellegrini D., Porcelli M.
This paper describes the main features of the NOSA-ITACA code, software for the structural analysis of masonry buildings of historical interest resulting from integration of the finite element code NOSA and the open-source platform SALOME. After a short description of the constitutive equation used to model the mechanical behaviour of masonry constructions, some details are given concerning the code's implementation. Then, the result of a static analysis of the "Voltone" in Livorno, performed via the NOSA-ITACA code, is presented with the aim of highlighting the important role of mathematical models and numerical tools in assessing the safety of historical masonry buildings.Source: 18th ICOMOS General Assembly and Symposium: "Heritage and Landscape as Human Values", Florence, Italy, 9-14 November 2014

See at: ISTI Repository Open Access | CNR ExploRA