Vanni Nicoletti

Pubblicazioni

Vanni Nicoletti

 

11 pubblicazioni classificate nel seguente modo:

Nr. doc. Classificazioni
6 4 Contributo in Atti di Convegno (Proceeding)
4 1 Contributo su Rivista
1 8 Tesi di dottorato
Anno
Risorse
2021
Monitoring the Modal Properties of an RC School Building during the 2016 Central Italy Seismic Swarm
JOURNAL OF STRUCTURAL ENGINEERING
Autore/i: Gara, F.; Arezzo, D.; Nicoletti, V.; Carbonari, S.
Classificazione: 1 Contributo su Rivista
Abstract: This paper presents results from the dynamic monitoring of a reinforced concrete school building located in Camerino (central Italy) during the seismic swarm following the first main shock of the Central Italy earthquake that occurred in August 2016. After the main shock of August 24th, ambient vibration tests were executed on the building to identify its modal dynamic behavior, which was assumed as benchmark to study changes in the structural response because of the subsequent events. A three-day dynamic monitoring was then performed with the aim of investigating changes in the dynamic behavior of the building subjected to ambient and seismic excitations. A procedure to identify the nonlinear response of the structure subjected to seismic events is presented, starting from an optimization methodology that permits the identification of the structure dynamics within time windows in which the building dynamic behavior can be considered linear time-invariant. Data show the variability of the modal properties, resonance frequencies, and damping ratios of the building, with the earthquake intensity.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/289951 Collegamento a IRIS

2021
Dynamic monitoring of buildings as a diagnostic tool during construction phases
JOURNAL OF BUILDING ENGINEERING
Autore/i: Nicoletti, V.; Arezzo, D.; Carbonari, S.; Gara, F.
Classificazione: 1 Contributo su Rivista
Abstract: The paper discusses the usefulness of the dynamic characterization of buildings based on the use of ambient vibration tests at different construction phases. The proposed experimental procedure, integrated with more conventional non-destructive in-situ tests for the estimation of the material mechanical properties, foresees the monitoring of the evolution of the building modal properties during the main construction phases. The monitoring makes it possible to assess the correctness of the construction through comparison with expected trends, and to consider possible countermeasures in case of unexpected behaviours. A case study, monitored during its construction, is presented to show the additional value of information obtained from the proposed experimental approach: (i) tests on the bare frame can be adopted to validate the design numerical model of the structure, in which non-structural elements are neglected in performing ultimate limit state verifications, (ii) the proposed monitoring allows the identification of the infills contribution on the building dynamics, providing useful information to address the interaction problem between structural and non-structural elements that may be detrimental at ultimates, and (iii) trends of resonance frequencies during the construction, validated through numerical applications, constitute an important tool for interpreting data from structural health monitoring system, as well as to establish alert thresholds of demand parameters (e.g. relevant to the building occupancy or structural damage).
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/293681 Collegamento a IRIS

2020
Expeditious methodology for the estimation of infill masonry wall stiffness through in-situ dynamic tests
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Nicoletti, V.; Arezzo, D.; Carbonari, S.; Gara, F.
Classificazione: 1 Contributo su Rivista
Abstract: In this paper a procedure to experimentally estimate the stiffness of masonry internal partitions and infill walls is proposed with the aim of providing a practical tool to reduce uncertainties in the finite element modelling of frame buildings when partitions and infills must be included. The proposed methodology, based on in-situ impact load tests and numerical modelling, is presented. The methodology is validated through an experimental campaign on a laboratory mock-up and applied to a real reinforced concrete frame building. The proposed methodology revealed capable to provide a very accurate estimate of the infill stiffness to be adopted in the building modelling.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/283984 Collegamento a IRIS

2020
Measurements of ambient vibrations for a cable-stayed bridge including the soil-foundation system
Proceedings of the International Conference on Structural Dynamic , EURODYN
Autore/i: Nicoletti, V.; Arezzo, D.; Carbonari, S.; Dezi, F.; Gara, F.
Editore: European Association for Structural Dynamics
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This paper deals with the dynamic characterization of a cable-stayed steel-concrete composite bridge located on the Saline river, close to Pescara in central Italy, carried out during the static proof load test. The bridge is 189 m long and is composed by 4 inclined steel pipe pylons that sustain a steel-concrete composite deck by means of 40 stay cables. During the proof test, an extensive experimental campaign is carried out to check the overall structural performance before the bridge openings to traffic. In detail, the main girder deflections, the axial loads on strands, the pylons displacements, and the bearings displacements were monitored through conventional and non-conventional techniques, such as the laser scanner technique. In addition, an accelerometer array is installed during the proof test to evaluate the dynamic characteristics of the structure in its loaded and unloaded conditions through ambient vibration measurements. Sensors are positioned on the deck, on two pylons and on the foundation system, in order to characterize the whole structural dynamic behavior, including the contribution of the soil-foundation compliance. With reference to the unloaded bridge, the latter issue is analyzed in this paper, focusing on the different restraint condition exerted by the soil-foundation system of the pylons, because of the different embedment of the reinforced concrete basements. It is shown that the soil-foundation compliance has greater effects on higher modes for the bridge at hand and that possible non-symmetries due to the different foundation degree of restraint can be suitably captured through ambient vibration tests. Data from experimental tests are crucial not only to check consistency between the design and the real structure before the opening to traffic, but also to calibrate refined finite element models to be used for the structural health monitoring of the bridge. In this sense, a reliable evaluation of the contribution of the soil-foundation system is mandatory, considering that the bridge, having foundations located in the riverbed, is prone to the scour hazard.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287438 Collegamento a IRIS

2020
Dynamic monitoring of bridges during static load tests: influence of the dynamics of trucks on the modal parameters of the bridge
JOURNAL OF CIVIL STRUCTURAL HEALTH MONITORING
Autore/i: Gara, F.; Nicoletti, V.; Carbonari, S.; Ragni, L.; Dall'Asta, A.
Classificazione: 1 Contributo su Rivista
Abstract: This paper presents results of an extensive experimental campaign carried out during the construction phases of a base-isolated bridge across the Potenza river in central Italy. The structure is constituted by a half-through steel arch bridge composed by two coupled weathering steel tubular arches sustained by thirty couples of hangers and by two approaching viaducts. The bridge has a continuous twin-girder steel–concrete composite deck. During construction, impact load tests were carried out on hangers as well as on other tie elements to estimate their tension force from the relevant resonance frequencies. During the proof test, relative displacements occurred between the upper and lower plates of the seismic isolators are measured for different loading conditions. In addition, ambient vibration tests are performed during the final static load tests to investigate the bridge dynamics subjected to different loading conditions. Comparisons of test results with the numerical predicted values contributed to evaluate the consistency between the design and the real structure at different construction stages. Dynamic identification tests contributed to identify the significance of the truck–bridge interaction in the interpretation of the bridge dynamics evaluated experimentally.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/273422 Collegamento a IRIS

2019
Identification of infill masonry walls stiffening contribution on the dynamic behaviour of steel frames
8th IOMAC - International Operational Modal Analysis Conference, Proceedings
Autore/i: Nicoletti, Vanni; Regni, Marco; Speranza, Elisa; Arezzo, Davide; Carbonari, Sandro; Gara, Fabrizio
Editore: International Operational Modal Analysis Conference (IOMAC)
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The paper deals with the influence of infill masonry walls on the dynamic behaviour of steel structures. The research is based on the experimental and numerical results obtained for a real scale laboratory mock-up, consisting of a one-storey two-bays steel-concrete composite frame. Ambient vibration tests followed by impact load tests were performed after the construction of the IMWs to estimate the dynamic properties of the entire structure and to investigate changes of modal parameters (natural frequencies and mode shapes) due to the contribution of the non-structural components. Furthermore, impact load tests were performed on some IMWs to identify their out-of-plane modal parameters; finally, a methodology to estimate parameters for a 2D modelling of the IMWs is proposed and validated. The numerical results show a very good agreement with the experimental ones, proving the reliability of the estimated IMWs stiffnesses through the proposed procedure.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267569 Collegamento a IRIS

2019
Influenza delle tamponature sul comportamento dinamico di strutture a telaio in acciaio: sperimentazione su un caso studio
Atti del XVIII Convegno ANIDIS L'ingegneria sismica in Italia
Autore/i: Nicoletti, Vanni; Arezzo, Davide; Carbonari, Sandro; Gara, Fabrizio
Editore: Pisa University Press srl
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: L’articolo riguarda un’estesa campagna sperimentale finalizzata all’analisi dell’influenza delle tamponature sul comportamento dinamico di strutture intelaiate in acciaio. La sperimentazione è stata condotta in laboratorio su un telaio in acciaio con soletta composta in c.a. e lamiera grecata, sul quale sono state eseguite prove di impatto, di vibrazione ambientale e di spinta e rilascio, per le quali vengono descritte le procedure seguite, la strumentazione adottata e i principali risultati ottenuti. Le prove sono state eseguite prima e dopo la realizzazione di tamponature leggere in laterizio forato e intonaco al fine di valutare il contributo fornito, in termini di rigidezza, sul comportamento dinamico globale del telaio soggetto ad azioni tali da mantenere la struttura e le pareti in campo elastico. Per concludere, viene presentato un confronto tra i risultati ottenuti con le diverse prove che, nonostante lascino tutte la struttura in campo elastico, sono caratterizzate da un diverso livello di eccitazione e forniscono risultati in alcuni casi piuttosto differenti.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269909 Collegamento a IRIS

2018
Experimental Evaluation of Infill Masonry Walls Stiffness for the Modelling of Non-Structural Components in R.C. Frame Buildings
Autore/i: Nicoletti, Vanni
Editore: Università Politecnica delle Marche
Classificazione: 8 Tesi di dottorato
Abstract: Solitamente le tamponature vengono trascurate nella modellazione delle strutture a telaio in cemento armato e solamente il loro contributo in termini di massa viene preso in considerazione, assumendo che la resistenza e la rigidezza delle stesse non influiscano sulla risposta strutturale. Questa pratica è supportata dal fatto che (i) generalmente allo stato limite ultimo le tamponature si considerano completamente danneggiate e, quindi, il loro contributo in termini di rigidezza è trascurabile, mentre (ii) allo stato limite di danno il valore dello spostamento di interpiano, ottenuto trascurando il contributo di rigidezza delle tamponature, può essere considerato a favore di sicurezza. Tuttavia, per edifici di importanza strategica, quali scuole, ospedali, caserme delle forze dell’ordine e dei Vigili del Fuoco, è cruciale preservare le tamponature da qualsiasi danno, anche per terremoti di entità severa, in modo da garantire il normale utilizzo dell’edificio durante la gestione dell’emergenza. Inoltre, questi edifici a volte sono sismicamente protetti con sistemi e dispositivi (smorzatori, isolatori, ecc…) il cui progetto richiede che sia tenuto in considerazione il reale comportamento dinamico della struttura (in termini di frequenze e/o spostamenti e/o velocità). Per questo diventa cruciale modellare accuratamente l’intera struttura, includendo le tamponature, e validare questo modello così ottenuto sulla base dell’evidenza sperimentale. La tipologia delle pareti e le loro procedure costruttive sono fonte di incertezze nella modellazione delle interazioni tra la struttura e gli elementi non strutturali. Quindi, una valutazione sperimentale delle proprietà di rigidezza dei pannelli di tamponatura potrebbe essere molto utile per valutare, all’interno del modello strutturale adottato per il progetto, il contributo in termini di rigidezza fornito alla struttura in c.a. da questi elementi non strutturali. In questa tesi viene presentata una procedura per realizzare modelli globali agli elementi finiti accurati di edifici a telaio in c.a. tamponati, basandosi su risultati ottenuti da analisi modali sperimentali e operative sviluppate rispettivamente su elementi non strutturali e sull’intero edificio. In particolare, sono stati eseguiti test di impatto con martello strumentato su pareti omogenee per identificarne i parametri modali (frequenze e forme modali) e per stimarne le proprietà meccaniche. Dopo di che, le tamponature sono state inserite nel modello strutturale globale agli elementi finiti, i cui parametri modali vengono confrontati con quelli derivanti da analisi modali operative basate su misurazioni di vibrazioni ambientali per valutarne l’accuratezza. In seguito, è stata condotta una campagna sperimentale su tre provini di tamponatura costruiti all’interno del Laboratorio di Prove di Materiali e Strutture della Facoltà di Ingegneria dell’Università Politecnica delle Marche. Questi provini sono stati realizzati con l’intento di riprodurre le caratteristiche di alcune delle tamponature testate in sito e su di essi vengono svolte prove sia dinamiche che statiche. Innanzi tutto, sono stati effettuati test ad impatto con martello strumentato per investigarne il comportamento dinamico fuori dal piano; successivamente sono state svolte prove di spinta laterale per investigare il comportamento statico nel piano dei pannelli soggetti a bassi livelli di forze orizzontali. I risultati sperimentali ottenuti sono stati utilizzati per calibrare modelli agli elementi finiti dei provini al fine di valutare l’esattezza delle proprietà meccaniche delle tamponature stimate in precedenza e secondo diversi approcci.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/253124 Collegamento a IRIS

2018
Experimental modal properties of a steel arch bridge during the static load test
Lecture Notes in Civil Engineering, 2018
Autore/i: Gara, Fabrizio; Nicoletti, Vanni; Roia, Davide; Dall'Asta, Andrea
Editore: Springer
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Base isolated steel arch bridges are very complex engineering systems whose behaviour may depend not only on an accurate design but also on its correct realization during all construction phases. One of the most effective method, fast and cheap, to check the global behaviour of the structure and the correctness of the design structural models is based on the comparison between modal parameters, in terms of frequencies and mode shapes, experimentally identified by means vibration measurements with those theoretically predicted by the structural models. This paper describes the dynamic test carried out during the standard static load test of a half-through steel arch bridge. The bridge is built over the Potenza river, in central Italy, and its structural design is characterized by some notable aspects: the river crossing is obtained by two coupled steel arches, having a span length around 115 m, and a steel-concrete composite deck sustained by thirty couples of steel hangers; the arches are supported on rubber bearing seismic isolators. An accelerometer array was installed over the bridge deck to study the evolution of the modal parameters of the structure at specific phases of the load test: first on the unloaded configuration, then on two different loaded configurations, made by placing trucks over the deck, and finally after the bridge unloading. Measurements of ambient vibrations were carried out and Operational Modal Analysis was performed to estimate modal properties of the deck. Experimental values of the resonance frequencies and related mode shapes are compared with those obtained with the predictive finite element model developed for design purposes and opportunely modified to account for the real conditions of the bridge during the tests. In particular, the dynamic interaction between bridge and trucks was investigated by considering trucks not only in terms of added mass but as dynamic systems characterized by mass, stiffness and damping properties. The obtained results show the effects of the trucks on the dynamic parameters of the bridge and allow the reliability assessment of the numerical model.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251330 Collegamento a IRIS

2018
Dynamic in situ tests for the calibration of an infilled R.C. Building F.E. model
EESMS 2018 - Environmental, Energy, and Structural Monitoring Systems, Proceedings
Autore/i: Nicoletti, Vanni; Gara, Fabrizio; Regni, Marco; Carbonari, Sandro; Dezi, Luigino
Editore: Institute of Electrical and Electronics Engineers Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259399 Collegamento a IRIS

2016
Dynamic Monitoring of an Isolated Steel Arch Bridge during Static Load Test
Proceedings of the 2016 IEEE Workshop on Environmental, Energy and Structural Monitoring Systems (EESMS)
Autore/i: Gara, F.; Nicoletti, V.; Roia, D.; Dezi, L.; Dall’Asta, A.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/240879 Collegamento a IRIS




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