Calibration of the dynamic behaviour of incomplete structures in archeological sites: The case of Villa Diomede portico in Pompeii

This paper reports the research activities carried out on Villa Diomede in Pompeii, built during the "Pre-Roman period" (i.e. the 3rd century BC) and discovered between 1771 and 1774 during the archaeological excavations. It is one of the greatest private buildings of Pompeii and it is located on the western corner of the modern archeological site. Three levels compose the building: the ground floor, the lower quadriportico with a square plan and a series of colonnades on the four sides around the inner garden and the cryptoportico. Villa Diomede was damaged by the strong earthquake occurred in AD 63 that caused the collapse of the western pillars of the quadriportico and later damaged after the big eruption of Vesuvius in AD 79. In June 2015 a series of nondestructive tests (NDT) were carried out by the authors in order to obtain information on the state of conservation of the building and to assess its structural behavior. Direct and tomographic sonic pulse velocity tests, ground penetrating radar, endoscopies and operational modal analysis were performed on the remaining structural elements on the two levels of the Villa. The present paper reports the main outcomes and findings of ambient vibration tests implemented to extract the modal parameters in terms of eigenfrequencies, mode shapes and damping ratios. Operational modal analysis and output-only identification techniques were applied to single stone pillars of the quadriportico structure and then to the entire square colonnade of Villa Diomede. Results are then used to study the soil-structure interaction at a local level and extend the gained information for the numerical calibration of the whole structure. Thanks to this methodology a detailed model updating procedure of the quadriportico was performed to develop reliable numerical models for the implementation of advance structural and seismic analysis of this "incomplete" archaeological structure

Finite element micro-modelling for the characterization of inclined head joints archaeological masonry: the case of Villa Diomede in Pompeii

Villa Diomede is a great roman building located on the western corner of the modern archaeological site of Pompeii, built during III century BC and discovered between 1771 and 1774 during archaeological excavations. The system is composed by three levels: the road level, the garden level, which hosts the portico structure, and the underground level. The building includes diverse types of masonry with a wide range of unit shapes, dimensions and materials (i.e. tuff, limestone, volcanic stone, clay brick etc.). Besides, an unconventional tuff masonry type was observed on some structures of the garden; it reveals inclined head joints, whose structural function is still unknown. The paper reports the numerical micro-modeling of this particular texture of masonry, where the constitutive materials (tuff units and mortar) are discretized. The main goal of the work is the assessment of inclined masonry joints as an aseismic detail compared with widespread traditional tuff running bond masonry. Micro models of masonry wallettes were created assigning a non-linear constitutive behavior, i.e. total strain crack model (with a parabolic behavior in compression and an exponential softening behavior in tension, whereas damage due to tensile cracking was modeled adopting a rotating crack model). Moreover, brittle 2D interfaces were modeled between mortar and units at inclined joints surfaces. The paper focuses on numerical prediction of compressive response of masonry models subjected to uniaxial compressive tests.Postprint (published version

SEISMIC STRENGTHENING OF EXISTING URM STRUCTURES THROUGH CLT ELEMENTS: NUMERICAL ANALYSIS OF THE APPLICATION OF A NOVEL INTERVENTION TECHNIQUE

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Mechanisms of nerve damage in neuropathies associated with hematological diseases: lesson from nerve biopsies

Despite the introduction of non-invasive techniques in the study of peripheral neuropathies, sural nerve biopsy remains the gold standard for the diagnosis of several neuropathies, including vasculitic neuropathy and neurolymphomatosis. Besides its diagnostic role, sural nerve biopsy has helped to shed light on the pathogenic mechanisms of different neuropathies. In the present review, we discuss how pathological findings helped understand the mechanisms of polyneuropathies complicating hematological diseases

La vibrazione focale in riabilitazione: osservazione clinica degli effetti funzionali in bambini affetti da PCI

Background La Vibrazione Focale può essere usata in riabilitazione sia per problematiche di tipo ortopedico che di tipo neurologico con diversi obiettivi: ridurre la spasticità, facilitare la contrazione muscolare per migliorare le attività funzionali, migliorare il controllo motorio e favorire la riorganizzazione motoria nei disturbi del movimento. Il protocollo repeated Muscle Vibration applicato attraverso lo strumento commerciale Crosystem® produce delle modificazioni plastiche della corteccia motoria primaria ed è in grado di modificare alcune attività funzionali come il cammino, anche in pazienti affetti da PCI in età evolutiva. L’intento di questo elaborato è quello di osservare le modificazioni funzionali ottenibili con il protocollo rMV in un contesto clinico in pazienti in età evolutiva affetti da paralisi cerebrale infantile. Materiali e metodi Il protocollo rMV consiste nell’applicazione di una vibrazione ad alta frequenza (100 Hz) e bassa ampiezza (300-500 μm) per dieci minuti tre volte al giorno per tre giorni consecutivi sullo stesso punto muscoloscheletrico, mentre lo stesso muscolo trattato viene mantenuto in leggera contrazione isometrica attraverso uno specifico strumento commerciale, denominato Crosystem®. In questo studio sono stati presi in considerazione bambini tra uno e diciotto anni con diagnosi di PCI affluenti ad uno studio privato. È stata fatta una valutazione iniziale da parte del fisioterapista della struttura per scegliere il/i punto/i muscoloscheletrici da trattare. Alla valutazione del fisioterapista è seguita la somministrazione di una scheda di rilevazione dati (Appendice 1) da parte del sottoscritto e la videoregistrazione di alcune attività funzionali importanti per il distretto trattato. Successivamente è stato erogato il trattamento con il protocollo rMV. La videoregistrazione è stata ripetuta alla fine del terzo giorno di trattamento e dopo trenta giorni a casa dai genitori. Sulla base delle videoregistrazioni è stata compilata da parte di un fisioterapista esterno una Goal Attainment Scale per ciascun bambino per un 8 obiettivo motorio specifico. Sono poi assegnati i punteggi delle GAS sulla base delle videoregistrazioni. È stato, inoltre, proposto ai genitori dei bambini, che hanno usufruito di tale trattamento affluenti al suddetto studio privato e non solo a quelli arruolati per la parte sperimentale, un questionario qualitativo/quantitativo (Appendice 3). Infine è stata condotta un’intervista informale nei bambini – arruolati nella parte sperimentale dello studio - che potessero dare delle risposte attendibili riguardo al trattamento. Risultati Sono stati arruolati otto pazienti corrispondenti ai criteri di inclusione ed esclusione. È stato calcolato l’Overall GAS score al t0, t1 e t2, rispettivamente prima, subito dopo e in media 32,3 giorni dopo il trattamento. Tale punteggio ha subito una variazione di + 18,17 al t1 e di + 14,91 al t2 rispetto a t0. In generale il trattamento ha prodotto degli effetti significativi per il 62,5% dei pazienti al t1 e per almeno il 50% al t2. Sono stati raccolti 11 questionari e 3 interviste. Da tali dati emerge che il trattamento con il protocollo rMV è molto apprezzato in quanto non invasivo e senza controindicazioni. Inoltre i risultati funzionali, quando presenti, sono osservabili anche dai familiari e dai bambini stessi. Conclusioni L’applicazione del protocollo rMV attraverso il Crosystem® produce degli effetti funzionali significativi in un contesto clinico in pazienti affetti da PCI in età evolutiva. Questi dati alimentano la possibilità di considerare la Vibrazione Focale come uno dei trattamenti complementari al percorso riabilitativo di ciascun bambino con questi disturbi di movimento

Soluzioni integrate con componenti in legno per la protezione sismica del patrimonio architettonico

I campi dell’Ingegneria e del Recupero del patrimonio esistente hanno visto, negli ultimi anni, una crescita costante dell’attenzione verso le tematiche della protezione sismica e, nel contesto dei cambiamenti climatici in atto, della sostenibilità, vista l’ormai palese necessità di migliorare, da tale punto di vista, il panorama delle costruzioni e del costruito, sia in termini di materiali impiegati che di consumi. In tale contesto, le componenti costruttive in legno sono state rivalutate grazie alle loro ottime caratteristiche strutturali accompagnate da una massa ridotta, che le rendono idonee all’impiego in zone sismiche, e alla loro sostenibilità, sia in funzione della valutazione del ciclo di vita, che delle proprietà di isolamento termico. Tra queste, il cosiddetto Cross Laminated Timber (CLT) ha avuto un notevole successo, legato anche alla sua velocità di assemblaggio, che si basa su connessioni a secco in acciaio. Tuttavia, queste sono anche legate a possibili riduzioni del comfort acustico dell’edifico, il cui superamento viene in genere realizzato mediante l’interposizione di una guaina elastomerica isolante. L’attività di ricerca, sperimentale e numerica, presentata in questa tesi, riguarda l’implementazione di nuove soluzioni integrate in legno (CLT), da implementarsi sia nei sistemi di nuova costruzione che all’interno del patrimonio architettonico esistente. Il tema dell’integrazione ha una duplice valenza, sia dal punto di vista delle prestazioni (strutturali, energetiche, acustiche), che della eventuale collaborazione con altri sistemi esistenti. Le prestazioni delle connessioni, tradizionali e ad isolamento acustico, sono caratterizzate sperimentalmente a scala locale e a scala globale, mediante prove distruttive a taglio e prove di identificazione dinamica su campioni a scala di edificio reale. La calibrazione di modelli numerici su tali prove ha permesso di indagare l’interazione tra la scala locale ed il comportamento globale dell’edificio. A partire dalla caratterizzazione locale delle connessioni, è stato progettato un sistema di collegamento dissipativo, la cui efficacia è stata valutata mediante l’applicazione numerica ad una parete di riferimento da letteratura. La conoscenza acquisita circa le componenti in legno, e la loro simulazione, ha permesso di validare una metodologia per il recupero di edifici esistenti in muratura. Questa è basata sulla valutazione delle prestazioni integrate strutturali ed energetiche di pareti accoppiate legno-muratura e la loro estensione ad un edificio. Tale approccio è stato definito Nested Building ed applicato ad un edificio esistente in muratura del XVII secolo, la cosiddetta ‘Cattedra’ nella zona alpina veneta, oggetto di numerose trasformazioni ed interventi nel corso degli anni.The research activities of Engineering and Restoration have recently moved towards the topics of seismic protection of buildings and selection of sustainable materials, from both hygrothermal performances (i.e., energy consumptions) and material points of view (e.g., Life Cycle Assessment). In such a contest, timber components have gained a renewed interest, thanks to their optimal structural characteristics per low mass, which make them suitable for seismic prone areas, and sustainability. Among these, Cross Laminated Timber (CLT) has a strong success in the construction market, mainly due to the dry assembling technique of such prefabricated panels, based on dry steel fasteners and brackets. Unfortunately, these are also related to possible reductions of acoustic comfort. To overcome it, insulation of joints is usually applied. The experimental and numerical research activity discussed in this Doctoral Thesis concerns the implementation of new timber-based integrated solutions, to be adopted in both new systems or built heritage. Integration theme concerns a double value, with reference to multiple performances addressed (structural, hygrothermal or acoustic) and potential embedment within other (existing) systems. Traditional and insulated connections have been characterized by junction-scale and building-scale specimens, through shear testing and dynamic identification, respectively. The updating of numerical model by mode parameters has led to the detection of joints influence on the overall behavior. Following, based on such local characterization, a yielding connection system has been designed, and its effectiveness assessed by pier-scale cyclic simulations. The acquired knowledge about timber (CLT) components and their simulation has led to the validation of a methodology for the refurbishment of masonry existing buildings. This is based on the assessment of integrated hygrothermal-structural performances of coupled CLT-masonry walls, and the further extension to a structural system. Such approach was named ‘Nested Building’ and applied to a masonry construction of XVII century, the so-called ‘Cattedra’ in the Italian Alpine region, which underwent various alterations during years

Optimization of Intervention Strategies for Masonry Buildings Based on CLT Components

Unreinforced masonry has been for centuries one of the most widespread constructive techniques for both massive structures and civil buildings (e.g., palaces, hospitals, houses), for the most still standing nowadays. Their future conservation relies on (i) their protection from main natural threats (e.g., earthquakes) and (ii) updating to current functionality and hygrothermal standards. In the former framework, existing masonry buildings proved to have some intrinsic vulnerabilities, depending on composition (units and binder) and structural typologies. Based on experience gathered from seismic events, various retrofitting techniques have been proposed. In such a context, the use of cross-laminated timber (CLT) components is a very promising solution, in terms of compatibility with built heritage and integration of seismic and hygrothermal performances. This paper aims at improving the knowledge of the structural performances of compound timber–masonry interventions by numerical simulations carried out at (i) pier scale and (ii) building full scale via finite element modeling and nonlinear static analyses (pushover). First, a coupled timber–masonry wall was simulated and underwent sensitivity analyses with the properties of both components varying; then, the optimized solution was applied to a case study to assess the intervention benefits, and the results were also cross-checked with those of more traditional interventions (e.g., grout injections)

Optimization of Intervention Strategies for Masonry Buildings Based on CLT Components

Unreinforced masonry has been for centuries one of the most widespread constructive techniques for both massive structures and civil buildings (e.g., palaces, hospitals, houses), for the most still standing nowadays. Their future conservation relies on (i) their protection from main natural threats (e.g., earthquakes) and (ii) updating to current functionality and hygrothermal standards. In the former framework, existing masonry buildings proved to have some intrinsic vulnerabilities, depending on composition (units and binder) and structural typologies. Based on experience gathered from seismic events, various retrofitting techniques have been proposed. In such a context, the use of cross-laminated timber (CLT) components is a very promising solution, in terms of compatibility with built heritage and integration of seismic and hygrothermal performances. This paper aims at improving the knowledge of the structural performances of compound timber–masonry interventions by numerical simulations carried out at (i) pier scale and (ii) building full scale via finite element modeling and nonlinear static analyses (pushover). First, a coupled timber–masonry wall was simulated and underwent sensitivity analyses with the properties of both components varying; then, the optimized solution was applied to a case study to assess the intervention benefits, and the results were also cross-checked with those of more traditional interventions (e.g., grout injections)

Numerical Prediction of the Seismic Behavior of Reassembled Columns in Ancient Structures: An Anastylosis Model for the Temple of Apollo Pythios in Gortyn (Crete)

Abstract: The Temple of Apollo Pythios in Gortyn (Crete, Greece) dates back to the mid\u20107th century BC. The temple underwent several transformations and an ultimate destruction over time that resulted in the current remains of a Roman colonnade composed of six fragmented stone columns lying on the ground within the naos. In addition, the region was struck by several earthquakes which contributed to the various changes. The analysis of the fragments composing the column portions and their geometric features provided a possible outline for their standing repositioning. Based on the current seismic hazard of the region, a predictive numerical model of the colonnade in the anastylosis conditions suggested the need for proper connections between the fragments and the bases to ensure their overall conservation as a compound structure. The comparison of various configurations of intervention and the simple superimposition of the fragments also provided details on the accomplishment of minimal and compatible solutions