Thesis Chapters by Valerio Sabbatini
Le masse accordate sono tra i più comuni ed affidabili sistemi di smorzamento delle azioni dinami... more Le masse accordate sono tra i più comuni ed affidabili sistemi di smorzamento delle azioni dinamiche. L'utilizzo di una massa esterna opportunamente dimensionata e collegata alla struttura esistente permette importanti miglioramenti delle performance dinamiche. Il presente elaborato propone la progettazione di un intervento di adeguamento sismico attraverso un sistema di masse accordate non convenzionale (non-conventional Tuned Mass Damper) che sfrutta la massa esistente dell'ultimo impalcato di un edificio in calcestruzzo armato.
A tale scopo, è stata effettuata la progettazione di un nuovo solaio di copertura in acciaio (sovrastruttura) opportunamente vincolato alla struttura esistente (sottostruttura) attraverso isolatori sismici flessibili HDRB.
The archaeological site of Pompeii includes a series of masonry towers belonging to the remains o... more The archaeological site of Pompeii includes a series of masonry towers belonging to the remains of the ancient aqueduct system, i.e. Castellum Aquae system. Among the fourteen water towers still standing, four of them (no. 1, 2, 3 and 4) have been recently investigated by non-destructive techniques (sonic waves, georadar, ambient vibration tests), aimed at gathering information on the constructive systems and the current conservation conditions, as well as data on the overall dynamic behaviour. Originally, the towers were crowned by a lead water container at their top, serving as collector of water for the distribution to the city. The different states of art of the towers are investigated in order to assess the different levels of vulnerability and damages. These types of structures are characterized by a highly non-linear dynamic response in which rocking and sliding motions take place.
Three different approaches are used to evaluate the vulnerability of masonry structures:
the kinematic approach is a fundamental method based on the equilibrium conditions; the main parameter is the geometry of the structure. The material characteristics are less relevant parameters as they influence only the position of the hinge. The finite element approach is a common method based on the numerical integration of the system equations; the main parameter is the mechanical characterization of the materials, the geometry is less relevant since a proper mesh is able to sufficiently represent the behaviour of the structure. The discrete element approach is a sophisticated numerical method based on the integration of the equation of motion; the main parameters are the mechanical characteristics of the materials (in particular on its interfaces) and the geometry, especially for the evaluation of the rocking behaviour.
The results of these analyses are here processed, discussed and compared in order to assess the seismic vulnerability of the towers.
Papers by Valerio Sabbatini
8th Euro-American Congress - REHABEND 2020, 2020
Case Studies in Construction Materials
Case Studies in Construction Materials
Buildings
A comprehensive study was carried out to integrate information from different sources and evaluat... more A comprehensive study was carried out to integrate information from different sources and evaluate the effects of induced vibrations on a temple. Historical analysis was fundamental to interpreting the evolution of the construction and defining the HBIM. Experimental data were implemented in the FEM of the site, including the temple, its foundations, and the soil stratifications. Sensitivity analysis was carried out to identify the most influential parameters, which were calibrated to reduce error with the experimental frequencies. The FEM was further optimized with the Douglas–Reid method, considering, simultaneously, modal frequencies and deformations. Two different nonlinear dynamic analyses were performed; one analysis studied the effect on the temple of the dynamically moving load of the tram, and the other analysis studied the response of the temple to three-dimensional accelerations applied at the base. The drawbacks of each simulation were identified by comparing the numeric...
Heritage
Nowadays, the research in the fields of conservation and restoration is focusing on recording lar... more Nowadays, the research in the fields of conservation and restoration is focusing on recording large amounts of data and information in order to obtain highly accurate surveys that include most details of constructions. Documenting and surveying are fundamental activities in achieving the successful preservation of cultural heritage, but also in implementing efficient strengthening interventions of structures. The applications of methods and techniques that link the disciplines of geometrical surveys and structural analyses are still fragmented, and further research is necessary to fully transfer site information into structural models. In this article, the authors propose a methodology with which to link different restoration fields, with the aim of highlighting the strengths and weaknesses of the interoperability between surveys (carried out through detailed restitution from point clouds), heritage building information modeling (HBIM), and structural analyses to connect three diffe...
12th International Conference on Structural Analysis of Historical Constructions, 2021
During the last decades, conservation and structural safety assessment of historical buildings ga... more During the last decades, conservation and structural safety assessment of historical buildings gained great importance, in particular, the prediction of the dynamic response of historical masonry constructions plays a central role in the structural analysis. In this scenario, finite element modelling proved to be the most common and available approach to study the behaviour of complex masonry structures, however the gap between numerical and experimental analysis may lead to erroneous results.
The building, known as the Temple of Minerva Medica, dates back to the 4th century A.D. The build... more The building, known as the Temple of Minerva Medica, dates back to the 4th century A.D. The building presents different critical aspects: first of all the monumental pillars rest on pre-existing archaeological sites and inhomogeneous layers of soils, moreover the integrity of the structure is endangered by severe vibrations induced by the frequent transit of the nearby trains and the local tramway. Due to the instability of the surviving portion of the dome (the main part collapsed in cia tion and consolidation interventions. These works restored the majesty and reliability of this monument that is undervalued and often forgotten. Onsite testing gained a fundamental role in the identification of the construction, in particular, Ambient Vibration Test (AVT) provides global information on the overall dynamic characteristics of the structures. This paper, through the case study of the Temple of Miner-va Medica, aims to prove the reliability of Operational Modal Analysis (OMA) in the identification of the dynamic behaviour of a large masonry building (natural frequencies, modal damping and modal deformations). Two sets of measurements were recorded by the laboratory of Proof testing and Research on Structures and Material (PRiSMa) sonable number of accelerometers, were suitably positioned and the dynamic response of the structure to wind and the surrounding traffic was recorded; the measurements of the two halves of the temple were processed and later merged through the Multi-Run technique in order to identify the dynamic behaviour of the entire structure.
12th International Conference on Structural Analysis of Historical Constructions, 2021
Heritage, 2022
In Roman Baths, the Romans employed barrel and groin vaults of great dimensions, with maximum spa... more In Roman Baths, the Romans employed barrel and groin vaults of great dimensions, with maximum span more than 20 m; simple tools of structural analysis of ancient wide span vaulted halls are still lacking, due to geometrical and material complexity. In this paper, we study the collapse behavior, under horizontal static action, of a corner cross vault of the Baths of Diocletian in Rome (Hall I). Two methods of analysis are here used: non-linear incremental finite element and limit analysis. In both cases, 3D models have been developed by means of UAV inspection, NDT measures, and AVT monitoring. The construction of the overall 3D geometry has been here afforded with a specific pre-processing approach. Midas commercial software has been employed for FEM analysis, assuming a constitutive law specifically developed for Roman concrete. In limit analysis, masonry is discretized as a system of interacting rigid bodies in no-tension and frictional contact. The computational code consists in ...
12th International Conference on Structural Analysis of Historical Constructions, 2021
The archaeological site of Pompeii is an extraordinary evidence of Roman architectural heritage w... more The archaeological site of Pompeii is an extraordinary evidence of Roman architectural heritage which comprehends a large number of masonry constructions, buried after the Vesuvius eruption in 79 AD. They were discovered in the XVIII century when renewed cultural interest induced numerous archaeological excavations. In this scenario, the remains of the Roman aqueduct system, i.e. Castellum Aquae system [1], includes a series of approximately 6 m height masonry water towers (WTs). Among the fourteen surveyed, four free-standing towers (i.e. no. 1, 2, 3 and 4) have been investigated in 2015 by means of non-destructive techniques (sonic pulse velocity tests, ground penetrating radar (GPR), ambient vibration tests), aimed at gathering information on the constructive systems and the current conservation state, as well as data on the overall dynamic behaviour. According to the on-site inspections outcomes, 3D finite element models of the towers were constructed and calibrated on the results of operational modal analysis (OMA) [3]. The model updating procedure was able to describe and simulate the soil-structure interaction, introducing a Winkler elastic soil model [2], and to define the elastic parameters of masonry. This paper describes the seismic vulnerability assessment of the four WTs, considering both equilibrium capacity and material strength, performing analytical kinematic analyses and numerical finite element modelling. Aiming at improving the previous studies [4], equivalent modal parameters (i.e. natural frequencies and mode shapes) are used to calibrate analytical models and furtherly refine FE model updating. The numerical models were generated using DIANA software [5], implementing a nonlinear constitutive law for masonry material, i.e. total strain crack model. Afterwards, sensitivity analyses are performed to calibrate both the elastic properties of materials and the Winkler springs' stiffness. Eventually, analytical kinematic approach and FE pushover analyses (with uniform and modal force distribution) are executed to assess the seismic vulnerability of the WTs, according to Italian code [6]. Results of the analyses are presented and discussed. The study was the occasion to compare the results of kinematic and numerical procedures applied to archaeological structures.
Journal of Civil Structural Health Monitoring, 2021
Understanding the behavior of historic structures that have undergone structural changes, restora... more Understanding the behavior of historic structures that have undergone structural changes, restorations, and damage over time is still a significant challenge for structural engineers, particularly in those countries subject to high seismic risk, such as Italy. The study of built heritage for its prevention and conservation is an active research topic, due to the numerous uncertainties present in historic structures. Finite element modelling has become the most common and accessible method to study the behavior of complex masonry structures, however, the gap between numerical and experimental analysis may lead to erroneous results. Model updating techniques can reduce the discrepancy between the behavior of the numerical models and the testing results. The goal of this work is to illustrate a methodology to integrate the information derived from local, global, and geotechnical investigations into the finite element model of the masonry historical church of San Giovanni in Macerata, c...
Heritage, 2021
The growing use of highly specialized tools has led to a better knowledge of the mechanical prope... more The growing use of highly specialized tools has led to a better knowledge of the mechanical properties of the structures, reducing the destructive tests. The paper is aimed to identify an investigation method capable of directing staff in the planning of non-destructive test. The experimental campaigns must be planned in order to optimize the number and the type of tests to limit invasiveness and impact. The proposed method has been organized in a logical scheme that permits, in five steps, to predict with a good approximation the critical sections for an optimal setup of testing instruments. This method has been applied to the Octagonal Hall in Diocletian’s Bath, to establish a better location for the dynamic endoscopy and tomographic tests. A geometrical model was built using the plans, elevations, sections provided by the National Roman Museum and the point cloud made through a drone. With HBIM (Heritage Building Information Modeling) it was possible to synthesize the information...
Applied Sciences
Analysis and diagnosis of historical masonry buildings are frequently affected by uncertainties d... more Analysis and diagnosis of historical masonry buildings are frequently affected by uncertainties due to unexpected behaviors caused by cumulative damage, material decay or transformations. This research work follows a methodology in the structural analysis of the historical masonry church of San Filippo Neri in Macerata, severely damaged after the Central Italy Earthquake occurred in October 2016. The PRiSMa laboratory (Proof testing and Research in Structures and Materials) of Roma Tre University carried out an extensive onsite testing campaign, including NDT tests as sonic tomography and endoscopy, and minor destructive technique as double flat jack test, together with dynamic monitoring under ambient vibrations, to investigate the state of conservation of the building. The onsite testing results were then implemented in an accurate finite element model, which was tuned up by means of global dynamic response provided by OMA (operational modal analysis) and updated, after the sensit...
DYNAMIC INTERACTION OF SOIL AND STRUCTURE (DISS_19) PROCEEDINGS OF THE 6th INTERNATIONAL WORKSHOP “Ten years after L’Aquila earthquake of April 6th 2009 The rebuilding of monuments and infrastructures” L’AQUILA, NOVEMBER 28th 2019, May 19, 2019
The building, known as the Temple of Minerva Medica, dates back to the 4th century A.D. The build... more The building, known as the Temple of Minerva Medica, dates back to the 4th century A.D. The building presents different critical aspects: first of all the monumental pillars rest on pre-existing archaeological sites and inhomogeneous layers of soils, moreover the integrity of the structure is endangered by severe vibrations induced by the frequent transit of the nearby trains and the local tramway. Due to the instability of the surviving portion of the dome (the main part collapsed in cia tion and consolidation interventions. These works restored the majesty and reliability of this monument that is undervalued and often forgotten. Onsite testing gained a fundamental role in the identification of the construction, in particular, Ambient Vibration Test (AVT) provides global information on the overall dynamic characteristics of the structures. This paper, through the case study of the Temple of Miner-va Medica, aims to prove the reliability of Operational Modal Analysis (OMA) in the identification of the dynamic behaviour of a large masonry building (natural frequencies, modal damping and modal deformations). Two sets of measurements were recorded by the laboratory of Proof testing and Research on Structures and Material (PRiSMa) sonable number of accelerometers, were suitably positioned and the dynamic response of the structure to wind and the surrounding traffic was recorded; the measurements of the two halves of the temple were processed and later merged through the Multi-Run technique in order to identify the dynamic behaviour of the entire structure.
COMPDYN 2019, 24-26 June 2019, Crete, Greece 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering Methods in Structural Dynamics and Earthquake Engineering, 2019
The paper describes the approach followed in the characterization of the structural behavior of t... more The paper describes the approach followed in the characterization of the structural behavior of the historical masonry church of San Filippo Neri in Macerata, severely damaged and condemned after the Central Italy Earthquake occurred in October 2016. The case study of San Filippo Neri is particularly interesting: first for the historical and artistic importance of the church furthermore for the evidences of recurrent structural damage. The laboratory of Proof and Research on Structures and Materials of Roma Tre University carried out an extensive onsite testing campaign-including geometric survey, flat-jack test and ambient vibration test-in order to investigate the state of the building. Operational modal analysis was used to assess the dynamic behavior of the church; the results of the testing campaign were interpreted and correlated with an accurate finite element model of the construction. The numerical model was finally tuned up based on the experimental results in order to match the dynamic behavior. The aim of the research is to set the first steps for an integrated approach able to fit and combine the results from experimental onsite testing and numerical modelling.
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Thesis Chapters by Valerio Sabbatini
A tale scopo, è stata effettuata la progettazione di un nuovo solaio di copertura in acciaio (sovrastruttura) opportunamente vincolato alla struttura esistente (sottostruttura) attraverso isolatori sismici flessibili HDRB.
Three different approaches are used to evaluate the vulnerability of masonry structures:
the kinematic approach is a fundamental method based on the equilibrium conditions; the main parameter is the geometry of the structure. The material characteristics are less relevant parameters as they influence only the position of the hinge. The finite element approach is a common method based on the numerical integration of the system equations; the main parameter is the mechanical characterization of the materials, the geometry is less relevant since a proper mesh is able to sufficiently represent the behaviour of the structure. The discrete element approach is a sophisticated numerical method based on the integration of the equation of motion; the main parameters are the mechanical characteristics of the materials (in particular on its interfaces) and the geometry, especially for the evaluation of the rocking behaviour.
The results of these analyses are here processed, discussed and compared in order to assess the seismic vulnerability of the towers.
Papers by Valerio Sabbatini
A tale scopo, è stata effettuata la progettazione di un nuovo solaio di copertura in acciaio (sovrastruttura) opportunamente vincolato alla struttura esistente (sottostruttura) attraverso isolatori sismici flessibili HDRB.
Three different approaches are used to evaluate the vulnerability of masonry structures:
the kinematic approach is a fundamental method based on the equilibrium conditions; the main parameter is the geometry of the structure. The material characteristics are less relevant parameters as they influence only the position of the hinge. The finite element approach is a common method based on the numerical integration of the system equations; the main parameter is the mechanical characterization of the materials, the geometry is less relevant since a proper mesh is able to sufficiently represent the behaviour of the structure. The discrete element approach is a sophisticated numerical method based on the integration of the equation of motion; the main parameters are the mechanical characteristics of the materials (in particular on its interfaces) and the geometry, especially for the evaluation of the rocking behaviour.
The results of these analyses are here processed, discussed and compared in order to assess the seismic vulnerability of the towers.
The laboratory of Proof and Research on Structures and Materials of Roma Tre University carried out an extensive onsite testing campaign – including geometric survey, flat-jack test and ambient vibration test – in order to investigate the state of the building. Operational modal analysis was used to assess the dynamic behavior of the church; the results of the testing cam- paign were interpreted and correlated with an accurate finite element model of the construc- tion. The numerical model was finally tuned up based on the experimental results in order to match the dynamic behavior.
The aim of the research is to set the first steps for an integrated approach able to fit and com- bine the results from experimental onsite testing and numerical modelling.