166 pubblicazioni classificate nel seguente modo:

Simplified Vulnerability Assessment of Historical Churches in Banat Seismic Region, Romania
INTERNATIONAL JOURNAL OF ARCHITECTURAL HERITAGE
Autore/i: Onescu, Iasmina; Lo Monaco, Anna; Grillanda, Nicola; Mosoarca, Marius; D’Amato, Michele; Formisano, Antonio; Milani, Gabriele; Clementi, Francesco; Fofiu, Mihai
Classificazione: 1 Contributo su Rivista
Abstract: Romania, a mid-eastern European country, has a moderate seismicity and a large stock of historical buildings and churches. One of the most important seismic areas of the country is the Banat area, which ranks as the second most seismic area in Romania, with shallow earthquakes of crustal type. Many Orthodox and Catholic churches can be found in the area, the majority of them having a central nave. The churches are built in masonry, with vaults and wooden frameworks, and they present valuable architectural-artistic details, including paintings made by recognized painters. Various forms of structural damage appeared to the historical churches after past earthquakes, depending on the architectural configuration. This paper illustrates a study made on six historic churches in the Banat region, to investigate seismic vulnerability with simplified methods. The study highlights the most vulnerable points of the historic religious structures and the importance of investigating in a quick and simplified way the seismic behavior of such important buildings for the local community. Moreover, the main novelty of the paper is the highlighting of the importance of the sustainability aspect in the process of heritage preservation, as simplified assessment procedures are essential for more resilient risk reduction policies.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/328751

Damage assessment of cultural heritage affected by last Italian earthquakes
INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS ICNAAM 2021
Autore/i: Giordano, Ersilia; Ferrante, Angela; Bianconi, Francesca; Clementi, Francesco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In the present work, the importance of considering the exact nonlinear and three-dimensional behavior of masonry structures is shown to study the damage assessment of complex structures. For this purpose, three churches damaged by the last earthquake are taken as cases study. The exact geometries of the structures are reconstructed, while information regarding the mechanical properties of materials is derived from previous investigations and literature references. Based on this information, the Finite Elements numerical models are realized. The models are used to performing static and dynamic analysis. The eigenvalue analyses are turn out to be good to identify, with low computational time, the elements more prone to be damaged, meanwhile the non-linear static analyses allowed to follow the damage evolution beyond the elastic field and to extract the seismic capacity.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/321274

The non-smooth tale of multiple leaf masonry walls
INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS ICNAAM 2021
Autore/i: Ferrante, Angela; Giordano, Ersilia; Schiavoni, Mattia; Clementi, Francesco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In the present paper has been reported the Non-Smooth Contact Dynamics method (NSCD) used for the damage evaluation of the multiple leaf masonry walls of the medieval fortress of Arquata del Tronto, strongly affected by the last Centre Italy earthquakes of August and October 2016. Pursuing this approach, a system of rigid blocks has been used for the assembly of the masonry structure. By means of contacts between blocks, which are governed by the Signorini’s impenetrability condition and by dry-friction Coulomb’s law, the building exhibits discontinuous dynamics. Finally, the NSCD method has proved to be an effective instrument for investigating the dynamical behavior of the masonry structures under the ground seismic accelerations. Indeed, several possible failure mechanisms have been confirmed through the numerical results, which have given a deep insight into the seismic vulnerability of this damaged medieval fortress.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/321273

Some recent advances and applications in Distinct Element modelling of masonry structures
Materials Research Proceedings
Autore/i: Schiavoni, M.; Giordano, E.; Clementi, F.
Editore: Association of American Publishers
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In this paper, advanced numerical models are used to study the progressive damage of a historic building, namely the Palazzo of Podestà and the Civic Tower of Accumoli (central Italy). The dynamic behaviour of the structure is analyzed following important seismic events such as those that occurred in 2016-2017. Discontinuous and continuous approaches are used. In the formers, the masonry response is represented both with Discrete Element Method (DEM) and the Non-Smooth Contact Dynamic (NSCD) method; in the latter the masonry nonlinearity is replicated using the Concrete Damage Plasticity (CDP) model. The numerical results showed a good correspondence of all the approaches with the real damage suffered by the structure after the seismic sequence.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/313888

Post-earthquake continuous dynamic monitoring of the twin belfries of the Cathedral of Santa Maria Annunziata of Camerino, Italy
Materials Research Proceedings
Autore/i: Standoli, G.; Clementi, F.; Gentile, C.; Lenci, S.
Editore: Association of American Publishers
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In this paper the results of over two years of continuous monitoring of the twin bell towers of the Cathedral of Camerino (Italy) are presented. The monitoring activity target is the evaluation of the dynamic behavior of the twin belfries after the damages occurred during the seismic events of 2016 and the application of fast securing. The experimental data are acquired in continuous using four triaxial MEMS accelerometers, two for each structure, on two opposite corners of the bell cells. Data processing is managed with an automatic system which elaborates the signals and executes Operational Modal Analysis to track the modal characteristics of the structures and their evolution in time. Correlation with environmental factors allows to discern the effect of climatic conditions on the variations of dynamics.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/313889

Seismic assessment of typical historical masonry churches in the Banat region, Romania - Part II
XIX ANIDIS Conference, Seismic Engineering in Italy
Autore/i: Monaco, Anna Lo; Grillanda, Nicola; Onescu, Iasmina; Fofiu, Mihai; Clementi, Francesco; D'Amato, Michele; Formisano, Antonio; Milani, Gabriele; Mosoarca, Marius
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This work focuses on the built heritage in Romania, with particular attention to five Orthodox masonry churches located in the Banat region, whose structural configuration is characterized by a unique nave and a bell tower included into the main façade. In a companion paper the seismic numerical investigations of Romanian masonry churches according to the Romanian regulations is presented. In this paper, firstly, a seismic performance comparison of the five churches with simplified risk assessment methods is conducted. Then, the preliminary results of a case study, obtained with both a macro-elements approach and a FEM model, are illustrated and commented. The numerical results here discussed belong to ongoing research campaign addressed to highlight the main characteristics of the seismic performance of the Romanian churches, also including the damage observed under seismic events, as well as to compare the results to each other.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/311532

Dynamic Identification and Automatic Updating of the Numerical Model of a Masonry Tower
Experimental Vibration Analysis for Civil Engineering Structures EVACES 2023 - Volume 1
Autore/i: Salachoris, Georgios Panagiotis; Standoli, Gianluca; Schiavoni, Mattia; Clementi, Francesco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The actual dynamic behavior of the masonry civic Clock tower in a little village, heavily damaged by the recent 2016 seismic sequence of central Italy, is thoroughly investigated by means of a detailed numerical model built and calibrated using the experimental modal properties obtained through Ambient Vibration Tests. The goal is to update the uncertain parameters of the Finite Element Model (elastic moduli, mass densities, constraints, and boundary conditions) to minimize the discrepancy between experimental and numerical dynamic features. Due to the high nonlinear dependency of the objective function of this optimization problem on the afore-mentioned parameters, and the likely possibility to get trapped in local minima, a fully automated Finite Element Model updating procedure based on genetic algorithms and global optimization is used, leading to the successful estimation of the uncertain parameters of the tower. The results allowed to create a reference digital replica of the current structural condition of the tower and to set the performance standards that will help to optimize the control of the structural integrity over time.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/321431

SEISMIC RESPONSE OF HISTORICAL MASONRY CHURCHES: THE CASE OF THE BANAT ROMANIAN REGION
COMPDYN Proceedings 2023 - 9th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering
Autore/i: Lo Monaco, A.; Grillanda, N.; Onescu, I.; Fofiu, M.; Clementi, F.; D'Amato, M.; Formisano, A.; Milani, G.; Mosoarca, M.
Editore: National Technical University of Athens
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The seismic events of the recent decades allowed us to comprehend the vulnerabilities of the historical built heritage and the fundamental role of prevention and safeguard strategies. This led us to study the seismic performances of historical constructions in Europe. This on-going research focuses on the built heritage in Romania, with particular attention to six typical masonry churches located in the Banat region, whose structural configuration is characterized by a long vaulted central nave and a bell tower included into the main façade. We firstly compare the seismic vulnerability of the six churches and estimate an intervention priorities scale through simplified risk assessment methods. Then, we present a more detailed vulnerability investigation focused on one of the churches, by means of global finite element modal linear analyses and assessment of local failures through adaptive limit analysis.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/324671

Numerical Assessment of Interacting Structural Units on the Seismic Damage: A Comparative Analysis with Different Modeling Approaches
APPLIED SCIENCES
Autore/i: Schiavoni, Mattia; Giordano, Ersilia; Roscini, Francesca; Clementi, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: The conservation of the historical and artistic heritage is one of the main priorities of Italian and international policy. The great variety of masonry buildings that make up this heritage is characterized by different combinations of materials and construction techniques. Then, several damage scenarios could be observed as a result, requiring appropriate retrofitting interventions. A rather accurate structural behavior analysis, especially for horizontal load conditions, allows for elaborating a correct seismic assessment. Albeit there are various numerical tools available to examine them, each one’s process starts by means of certain assumptions that could not be applied indiscriminately. This paper aims to compare two different types of modeling techniques to evaluate their strengths and weaknesses. To achieve this goal, an earthquake-damaged complex in Central Italy was chosen as a case study. The structure was modeled using a finite element (continuous) and a distinct element (discontinuous) method. Both approaches underwent a nonlinear dynamic analysis using the strong motions recorded during the 2016 seismic sequence. The results show that both approaches can evaluate the weak structural points. However, in some cases, the distinct element method appeared more accurate in reproducing the cracks.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/310096

Discontinuous Dynamics of Santa Maria Annunziata Church Under Seismic Loading: A Non-smooth Contact Dynamics Approach
Structural Analysis of Historical Constructions SAHC 2023 - Volume 2
Autore/i: Schiavoni, Mattia; Standoli, Gianluca; Bianconi, Francesca; Giordano, Ersilia; Clementi, Francesco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The dynamics the Santa MariaAnnunziata church located in Camerino (Macerata province, Italy), subjected to transversal dynamic loadings has been analysed by using a distinct element code which implements theNon-SmoothContact dynamics method. Since the contact between blocks is governed by the Signorini’s impenetrability condition and the dry-friction Coulomb’s law, the church exhibit discontinuous dynamics. The sliding motions of blocks are non-smooth functions of time. Numerical simulations are performed with the aim of investigating the influence of the friction coefficient and of some past retrofitting interventions on the global response. The results obtained are compared with the real damage that the Church suffered following the seismic sequence in central Italy in 2016, and for this reason the four main shock that strocked the area were used in the numerical analyses. A good agreement between the numerical and the real damages are finally obtained but it might be interesting to elaborate additional models in which the building presents different degrees of connection with the towers.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/321411

DIFFERENT MODELING APPROACHES APPLIED TO A RESILIENT MASONRY STRUCTURE
COMPDYN Proceedings2023 - Prooceedings of the 9th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering
Autore/i: Schiavoni, Matti; Giordano, Ersilia; Roscini, Francesca; Clementi, Francesco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In this paper, advanced numerical models are used to study the progressive damage of a historic building, namely the Palazzo of Podestà and the Civic Tower of Accumoli (central Italy). The dynamic behaviour of the structure is analyzed following important seismic events such as those that occurred in 2016-2017. Discontinuous and continuous approaches are used. In the formers, the masonry response is represented both with Discrete Element Method (DEM) and the Non-Smooth Contact Dynamic (NSCD) method; in the latter the masonry nonlinearity is replicated using the Concrete Damage Plasticity (CDP) model. The numerical results showed a good correspondence of all the approaches with the real damage suffered by the structure after the seismic sequence.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/323551

Numerical modeling of a majestic masonry structure: A comparison of advanced techniques
ENGINEERING FAILURE ANALYSIS
Autore/i: Schiavoni, M.; Giordano, E.; Roscini, F.; Clementi, F.
Classificazione: 1 Contributo su Rivista
Abstract: The present study aims to provide a comparative analysis between discontinuous models (DM) and continuous models (CM) for the analysis of majestic masonry structures subjected to seismic events. Specifically, the study models the ‘Santa Maria Annnuziata’ church damaged after the Central Italy earthquake sequence in 2016 and 2017 years. The DM is evaluated using different types of interaction laws between blocks: the Discrete Element Method (DEM) and the Non-Smooth Contact Dynamic method (NSCD). The nonlinearity of the material in the CM, instead, is considered using the Concrete Damage Plasticity model (CDP). To assess the models' effectiveness in identifying vulnerable elements, non-linear dynamic analysis is performed through the main earthquake events recorded nearby the church during the Central Italy earthquake. Following this, the models are subjected to the 7.8- magnitude earthquake that occurred in February 2023 in Turkey to observe the damage evolution under higher magnitude events. The primary objective of this study is to improve the understanding of the strengths and weaknesses of both models and their potential applications in the analysis of historic masonry structures.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/314805

Dynamic identification and numerical model updating of an old bell-tower in Marche Region (Italy)
INTERNATIONAL JOURNAL OF MASONRY RESEARCH AND INNOVATION
Autore/i: Giordano, E; Ferrante, A; Salachoris, Gp; Schiavoni, M; Clementi, F; Lenci, S
Classificazione: 1 Contributo su Rivista
Abstract: In this paper, the dynamic characterisation of the civic bell-tower of Rotella (a small village in the Marche Region, Central Italy) is presented. The tower after being monitored, using four tri-axial piezo-electric accelerometers, and obtaining its dynamic characteristics, was modelled through a finite element software. The difference between measured and real values has been smoothed out by acting on all unknown parameters such as Young's moduli, thus obtaining a model with frequency differences, compared to reality, less than 5% and the MAC values between the modal shapes close to the unit.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/320492

Comparison between Bayesian updating and approximate Bayesian computation for model identification of masonry towers through dynamic data
BULLETIN OF EARTHQUAKE ENGINEERING
Autore/i: Monchetti, Silvia; Viscardi, Cecilia; Betti, Michele; Clementi, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: Model updating procedures based on experimental data are commonly used in case of historic buildings to identify numerical models that are subsequently employed to assess their structural behaviour. The reliability of these models is closely related to their ability to account for all the uncertainties that are involved in the knowledge process. In this regard, to handle these uncertainties and quantify their propagation, Bayesian inference is frequently employed being able to deal with the effects of parameter uncertainty, observation errors and model inadequacy. The computation of the posterior distribution through Bayesian inference needs–however–the evaluation of the likelihood function, which requires solving complex multi-dimensional integration problems. To bridge this shortcoming, the paper compares two Bayesian inference approaches to show how different approximations affect the results of simulated inference: a discrete approach for the likelihood computation in the Bayesian Model Updating (BMU) and a Monte Carlo likelihood-free method known as Approximate Bayesian Computation (ABC) are reported. As reference, the typology of historic masonry towers was considered by using their natural frequencies as experimental data for model updating. The two procedures provide very similar results supporting the validity of both methods despite ABC turns out to be a more flexible approach.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/313108

Evolutionary numerical model for cultural heritage structures via genetic algorithms: a case study in central Italy
BULLETIN OF EARTHQUAKE ENGINEERING
Autore/i: Salachoris, Georgios Panagiotis; Standoli, Gianluca; Betti, Michele; Milani, Gabriele; Clementi, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: In this paper the actual dynamic behavior of the civic Clock tower of Rotella, a little village in central Italy heavily damaged by the recent 2016 seismic sequence, is thoroughly investigated by means of a detailed numerical model built and calibrated using the experimental modal properties obtained through Ambient Vibration Tests. The goal is to update the uncertain parameters of two behavioral material models applied to the Finite Element Model (elastic moduli, mass densities, constraints, and boundary conditions) to minimize the discrepancy between experimental and numerical dynamic features. A sensitivity analysis was performed with the definition of a metamodel to reduce the computational strain and try to define the necessary parameters to use for the calibration process. Due to the high nonlinear dependency of the objective function of this optimization problem on the parameters, and the likely possibility to get trapped in local minima, a machine learning approach was meant. A fully automated Finite Element Model updating procedure based on genetic algorithms and global optimization is used, leading to tower uncertain parameters identification. The results allowed to create a reference numerical replica of the structure in its actual health state and to assess its dynamic performances allowing better control over their future evolution.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/310488

Seismic assessment of Romanian Orthodox masonry churches in the Banat area through a multi-level analysis framework
ENGINEERING FAILURE ANALYSIS
Autore/i: Lo Monaco, Anna; Grillanda, Nicola; Onescu, Iasmina; Fofiu, Mihai; Clementi, Francesco; D'Amato, Michele; Formisano, Antonio; Milani, Gabriele; Mosoarca, Marius
Classificazione: 1 Contributo su Rivista
Abstract: This paper aims to show some results of seismic assessment of Romanian Orthodox existing masonry churches, by extending the multi-level approach proposed by the Italian directive for seismic risk evaluation of cultural heritage. To this scope, a sample of six existing churches is examined, belonging to a church typology characterized by a single vaulted nave and a bell tower incorporated into the main façade. All churches considered in this study are located in the Banat region, which is an area with a medium-high seismic hazard. Firstly, territorial Level of Valuations (LV0 and LV1) are conducted on the churches sample examined. Afterwards, local (LV2) and global (LV3) valuations are performed on a case study, the Învierea Domnului church assumed representative of all the churches sample under consideration. In particular, local analyses are performed on some church architectural portions with the kinematic limit analysis. Whereas, global analyses are conducted with non-linear push-over approach. Comments and comparisons of the obtained results are reported for each LV examined.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/320771

Advanced numerical insights for an effective seismic assessment of historical masonry aggregates
ENGINEERING STRUCTURES
Autore/i: Schiavoni, M.; Giordano, E.; Roscini, F.; Clementi, F.
Classificazione: 1 Contributo su Rivista
Abstract: The structural assessment of ancient masonry structures is still a challenging task. The main reasons have been related to the shortage of information in the materials’ characterization along with the complex geometry and different evolutions of its constituents’ parts through the time. Scientific studies on the evaluation of the structural capacity and design of these masonry buildings have reported several modelling techniques. The goal of this work is to investigate the effectiveness of different numerical approaches in the simulation of the cyclic behaviour of historic masonry buildings under seismic loads. In addition, the damage level of the structural interconnections will be evaluated and what extent they affect the global instability. The specific case study seeks to examine an ancient palace with its civic tower hit by the 2016 Central Italy earthquake. A couple of masonry modelling are used: the first one is discontinuous (DM) and the second one is continuous (CM). Two models were set: one model replicated the structure as a whole, the other one considered only the tower. The DMs were studied with 3DEC© and LMGC90© software, where, in turn, different contact conditions were implemented. In parallel, the CMs were analysed with the Midas FEA NX©. The present research offers significant outcomes obtained from the non-linear dynamic analyses performed using the proper sequence recorded in that seismic event. Likewise, this document underlines the importance of the correct modelling techniques definition, based on the state of the case study, especially when an isolated tower is considered.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/313107

Unveiling the complexity of twin church bells dynamics using ambient vibration tests
INTERNATIONAL JOURNAL OF MASONRY RESEARCH AND INNOVATION
Autore/i: Ferrante, A.; Giordano, E.; Standoli, G.; Bianconi, F.; Clementi, F.; Lenci, S.
Classificazione: 1 Contributo su Rivista
Abstract: On the Italian territory, many monumental structures need to be preserved. Given their great historical and architectural value, it is essential to use minimally invasive, but effective, techniques able to evaluate their current structural capabilities and monitor their structural health. The technique that currently appears most appropriate is the ambient vibration monitoring, which, through the analysis of recorded accelerometric time-histories in operating conditions, returns the current dynamic properties of the structure. This work shows the results of the short-term monitoring carried out on the two towers of the San Francesco Church, located in the city of Ascoli Piceno. Modal identification allowed obtaining its frequencies, modal shapes, and damping. With these data, the finite element model of the complex was calibrated, acting on the elastic parameters of the masonry, making numerical modal shapes and frequencies match with the experimental results.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/320831

Dynamic identification and automatic updating of the numerical model of a masonry tower
2023 IEEE International Workshop on Metrology for Living Environment (MetroLivEnv)
Autore/i: Salachoris, Gp; Standoli, G; Schiavoni, M; Clementi, F
Editore: IEEE
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The actual dynamic behavior of the masonry civic Clock tower in a little village, heavily damaged by the recent 2016 seismic sequence of central Italy, is thoroughly investigated by means of a detailed numerical model built and calibrated using the experimental modal properties obtained through Ambient Vibration Tests. The goal is to update the uncertain parameters of the Finite Element Model (elastic moduli, mass densities, constraints, and boundary conditions) to minimize the discrepancy between experimental and numerical dynamic features. Due to the high nonlinear dependency of the objective function of this optimization problem on the aforementioned parameters, and the likely possibility to get trapped in local minima, a fully automated Finite Element Model Updating procedure based on genetic algorithms and global optimization is used, leading to the successful estimation of the uncertain parameters of the tower. The results allowed to create a reference digital replica of the current structural condition of the tower and to set the performance standards that will help to optimize the control of the structural integrity over time.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/320851

Evaluation of Dynamic Properties of Trees Subjected to Induced Vibrations
APPLIED SCIENCES
Autore/i: Grande, E; Giordano, E; Clementi, F
Classificazione: 1 Contributo su Rivista
Abstract: The preservation of trees in urban and archeological areas is a theme of particular relevance. Modern systems of monitoring, together with approaches for deriving the main characteristics of trees influencing their response toward extreme events, are nowadays at the basis of a growing number of studies. The aim of the present paper is the dynamic identification of trees carried out by employing an approach which combines a simple data-acquisition system, direct and ambient sources of excitation, and different data-processing methods. In particular, using a single accelerometer placed at different sections of the trunk and considering excitations induced by either pulling tests or ambient vibrations, the derivation of the main frequencies and levels of modal damping characterizing the dynamic response of a sour cherry tree (Prunus cerasus) is carried out. A finite element model of the tree is also carried out to support the validation of the proposed approach and further analyze the derived outcomes. The obtained results underline the feasibility of the proposed approach in deriving information useful for assessing the behavior of trees toward dynamic actions and, consequently, of particular relevance for the identification of possible damages induced by variations in terms of dynamic characteristics (frequencies) and damping.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/319031

Out-of-plane seismic response of a masonry facade using distinct element methods
INTERNATIONAL JOURNAL OF MASONRY RESEARCH AND INNOVATION
Autore/i: Schiavoni, Mattia; Ferrante, Angela; Salachoris, Georgios Panagiotis; Mariotti, Chiara; Clementi, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: Damage surveys after earthquakes showed that unreinforced masonry buildings are prone to local failure modes related to out-of-plane mechanisms of walls caused by the poor connection with the orthogonal walls. Otherwise, if the masonry element rises isolated it may be subject to overturning mechanisms rather than in-plane collapse. Nowadays, several methods can be used to evaluate collapses. These methods require quite a high computational cost, not beneficial to practitioners. Advanced numerical models can be applied, such as the discrete element and non-smooth contact dynamics methods, which treat the masonry as a set of either rigid or deformable blocks that can slide and impact each other. In this paper, an ancient (isolated) masonry wall is analysed, and the results provide the first comparison between two numerical models to estimate the influence of the intervention placed on the top of the wall.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/310487

Numerical prediction of the mechanical behavior of TRM composites and TRM-strengthened masonry panels
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Giordano, E.; Masciotta, M. G.; Clementi, F.; Ghiassi, B.
Classificazione: 1 Contributo su Rivista
Abstract: The work concerns the detailed finite element modelling of multiscale experimental tests performed on glass-Textile Reinforced Mortars (TRM) with the aim of investigating the complex three-dimensional aspects associated with the TRM behavior and understanding what parameters are crucial for the correct simulation and prediction of the composite’s response at each scale. The investigation ranges from materials to structural scale. Each sample’s component and its interfaces are modeled individually. The results show that the 3D micro-modelling successfully replicates the experimental TRM response at different scales by using consistent materials parameters in all the simulation levels, proving a comprehensive understanding of the composite behavior and performance.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/319011

Dynamic characterisation and numerical model updating of a historical complex
INTERNATIONAL JOURNAL OF MASONRY RESEARCH AND INNOVATION
Autore/i: Standoli, Gianluca; Ferrante, Angela; Giordano, Ersilia; Bianconi, Francesca; Clementi, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: The world is full of historical structures that must be preserved. Given their considerable value, nothing or minimally invasive techniques must be adopted to monitor their health and improve their structural capacity. The Operation Modal Analysis (OMA) is currently the most popular non-invasive methodology to monitor them. Indeed, it allows to derive the dynamic characteristics of the structures through acceleration appropriately positioned sensors. The OMA is employed in the current paper to study a historical complex in the Marche region hinterland (central Italy). First, the dynamic monitoring is carried out to extract the dynamic parameters of the structure. The obtained data are then employed to realize a realistic numerical model by acting on uncertain parameters such as boundary conditions and material parameters.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/310489

Seismic Assessment of Typical Historical Masonry Churches in Banat region, Romania - Part I
Procedia Structural Integrity
Autore/i: Monaco, A. L.; Grillanda, N.; Onescu, I.; Fofiu, M.; Clementi, F.; D'Amato, M.; Formisano, A.; Milani, G.; Mosoarca, M.
Editore: Elsevier B.V.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The Banat seismic area in Romania is characterized by shallow earthquakes that generate in historic buildings different failure mechanisms. Religious buildings represent one of the most important historical buildings in Romania, with interesting structures and beautiful architectural details, but many of them in a poor conservation state. The failure mechanisms of the historical Romanian Baroque churches recorded after the earthquakes of 1990 and 1991 are due to the high value of the vertical components of the seismic action, the reduced number of cycles. The article presents the values of the seismic risk factor determined for three churches: Chizatau, Beregsau Mare and Birda churches with the ETABS software according to the Romanian design code P100-3 / 2019 in which the effects of the vertical seismic components are not taken into analysis.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/325051

Post-earthquake continuous dynamic monitoring of the twin belfries of the Cathedral of Santa Maria Annunziata of Camerino, Italy
Procedia Structural Integrity
Autore/i: Standoli, G.; Clementi, F.; Gentile, C.; Lenci, S.
Editore: Elsevier B.V.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In this paper the results of over two years of continuous monitoring of the twin bell towers of the Cathedral of Camerino (Italy) are presented. The monitoring activity target is the evaluation of the dynamic behavior of the twin belfries after the damages occurred during the seismic events of 2016 and the application of fast securing. The experimental data are acquired in continuous using four triaxial MEMS accelerometers, two for each structure, on two opposite corners of the bell cells. Data processing is managed with an automatic system which elaborates the signals and executes Operational Modal Analysis to track the modal characteristics of the structures and their evolution in time. Correlation with environmental factors allows to discern the effect of climatic conditions on the variations of dynamics.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/325052

Behavior of Existing Structures under Earthquakes: Advancements in Analysis Methods and Retrofitting Systems
AIP Conference Proceedings - International Conference on Numerical Analysis and Applied Mathematics 2020, ICNAAM 2020
Autore/i: Clementi, F.; Formisano, A.; Milani, G.; Mosoarca, M.
Editore: American Institute of Physics Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/300366

THE NON-SMOOTH TALE OF ACCUMOLI CIVIC TOWER
WCCM-APCOM 2022 - 15th World Congress on Computational Mechanics and 8th Asian Pacific Congress on Computational Mechanics: Pursuing the Infinite Potential of Computational Mechanics
Autore/i: Schiavoni, M.; Giordano, E.; Clementi, F.
Editore: International Centre for Numerical Methods in Engineering, CIMNE
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In this paper, advanced numerical models are used to study the progressive damage of a historic building, namely the Palazzo of Podestà and the Civic Tower of Accumoli (central Italy). The dynamic behaviour of the structure is analyzed following important seismic events such as those that occurred in 2016-2017. Discontinuous and continuous approaches are used. In the formers, the masonry response is represented both with Discrete Element Method (DEM) and the Non-Smooth Contact Dynamic (NSCD) method; in the latter the masonry non linearity is replicated using the Concrete Damage Plasticity (CDP) model. The numerical results showed a good correspondence of all the approaches with the real damage suffered by the structure after the seismic sequence.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/321091

Structural health monitoring and NDT of masonry structures: Research and practice
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Adam, José M.; Betti, Michele; Clementi, Francesco; Ivorra, Salvador
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/293441

Seismic Assessment of a Masonry Structure Damaged by Central Italy Earthquake
AIP Conference Proceedings - International Conference on Numerical Analysis and Applied Mathematics 2020, ICNAAM 2020
Autore/i: Giordano, E.; Ferrante, A.; Clementi, F.; Lenci, S.
Editore: American Institute of Physics Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The present work shows the seismic vulnerability analysis of a building located in Matelica, a village that has reported extensive damages, especially to the monumental historical structures, after the Central Italy Earthquakes. The building is studied with local and global analysis, these last are performed using accurate 3D Finite Element Models where the post-elastic behavior of masonry is considered by the Total Strain Crack Model. The study showed as the use of non-linear static analysis, in addition to be useful to evaluate the seismic capacity, can reproduce with good approximation the cracks provoke by the quakes. After the estimation of actual capacity, the improvement of a seismic retrofitting intervention is evaluated
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/300364

Application of a Non-Invasive Technique for the Preservation of a Fortified Masonry Tower
INFRASTRUCTURES
Autore/i: Giordano, Ersilia; Marcheggiani, Laura; Formisano, Antonio; Clementi, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: The Cultural heritage spread all over the World needs to be preserved with systems that do not compromise its architectural and historical value. Nowadays, the most advanced technology available is the ambient vibration test. It allows to obtain the current frequencies, modal shapes, and damping of structures, without being invasive. The comparison between different monitoring campaigns and their use in combination with Finite Element models can give an insight into the state of structures’ health. This paper presents two ambient vibration tests performed on a fortified masonry tower in the Marche region of Italy, carried out after one year each other, with different temperature and humidity conditions. To extract the structure’s dynamic parameters both a time and a frequency domain approaches were used. The comparison between the parameters obtained during the two experimental campaigns showed similar frequencies and modal shapes underlining that no damage occurred and that the dynamic response of the tower does not suffer temperature and humidity variations. In addition, the steps carried out for a first attempt manual calibration of the tower’s Finite Element model are shown. The match between the numerical model and the experimental data is evaluated through the absolute frequencies’ errors and the Modal Assurance Criteria between the modal vectors. The calibrated numerical model can be used for future and accurate assessment of the tower’s structural capacity.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/296582

POINT CLOUD EXPLOITATION FOR STRUCTURAL MODELING AND ANALYSIS: A RELIABLE WORKFLOW
INTERNATIONAL ARCHIVES OF THE PHOTOGRAMMETRY, REMOTE SENSING AND SPATIAL INFORMATION SCIENCES
Autore/i: Lucidi, A.; Giordano, E.; Clementi, F.; Quattrini, R.
Classificazione: 1 Contributo su Rivista
Abstract: The digitization and geometric knowledge of the historical built heritage is currently based on point cloud, that rarely or only partially is used as digital twin for structural analysis. The present work deals with historical artefacts survey, with particular reference to masonry structures, aimed to their structural analysis and assessment. In detail, the study proposes a methodology capable of employing semi-directly the original data obtained from the 3D digital survey for the generation of a Finite Element Model (FEM), used for structural analysis of masonry buildings. The methodology described presents a reliable workflow with twofold purpose: the improvement of the transformation process of the point cloud in solid and subsequently obtain a high-quality and detailed model for structural analyses. Through the application of the methodology to a case study, the method consistency was assessed, regarding the smoothness of the whole procedure and the dynamic characterization of the Finite Element Model. The main improvement in respect with similar or our previous workflows is obtained by the introduction of the retopology in data processing, allowing the transformation of the raw data into a solid model with optimal balancing between Level of Detail (LOD) and computational weight. Another significant aspect of the optimized process is undoubtedly the possibility of faithfully respecting the semantics of the structure, leading to the discretization of the model into different parts depending on the materials. This work may represent an excellent reference for the study of masonry artefacts belonging to the existing historical heritage, starting from surveys and with the purpose to structural and seismic evaluations, in the general framework of knowledge-based preservation of heritage.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/292305

Combining operational modal analysis and genetic algorithms to understand the actual structural behavior of historical constructions
COMPDYN Proceedings
Autore/i: Standoli, G.; Salachoris, GEORGIOS PANAGIOTIS; Masciotta, M. G.; Clementi, F.
Editore: National Technical University of Athens
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Evolution of technologies both in the fields of in situ investigations and Finite Element (FE) modeling strongly enhanced the possibility to understand the structural dynamic behavior of masonry historical constructions, allowing a periodic or continuous analysis of their response to environmental, anthropic, and exceptional actions and the formulation of accurate hypotheses about their future behavior, which is fundamental for Cultural Heritage preservation. In order to improve the assessment of the health status of historical buildings, inverse methods re-sorting to dynamic identification techniques are often used to provide experimentally verified data for the accurate calibration of FE models representative of the investigated structures. In this paper, vibration-based identification methods are coupled with an automatic FE model updating procedure to study the dynamic behavior of the Civic Tower of Ostra, Italy, and obtain baseline information for future comparative analyses. The experimental data obtained from two different campaigns of ambient vibration tests are used to update the mechanical characteristics of the detailed FE model of the tower. The updating process, unsolvable via common calibration procedures, is automatically managed through a powerful bio-inspired tool, i.e. the Genetic Algorithm (GA), allowing to closely reproduce the actual behavior of the tower.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/293923

Dynamic Identification and Monitoring of a New Highway Bridge
Civil Structural Health Monitoring. CSHM 2021
Autore/i: Marcheggiani, Laura; Clementi, Francesco; Formisano, Antonio
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/292049

Modal-based FE model updating via genetic algorithms: Exploiting artificial intelligence to build realistic numerical models of historical structures
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Standoli, Gianluca; Salachoris, Georgios Panagiotis; Masciotta, Maria Giovanna; Clementi, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: Cultural Heritage preservation requires the combination of in situ investigations and accurate Finite Elements models in order to correctly interpret the empirical evidence and successfully apply advanced structural analyses for health assessment purposes, allowing to infer about the future evolution of the structural response and timely detect deviations from the expected behaviour. In this paper the actual dynamic behaviour of the Civic Tower of Ostra, Italy, is thoroughly investigated by means of a detailed numerical model built and calibrated using the experimental modal features estimated through field dynamic testing. To this end, a fully automated Finite Element Model Updating procedure based on genetic algorithms and machine learning is conceived and employed, allowing the successful estimation of the unknown material properties of the tower, considering both isotropic and orthotropic behavioural models for masonry. The results enabled to establish baseline information on the current structural condition of the heritage and to set performance standards that will serve to optimise the control of the structural integrity over time.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/291691

“Scaglia Rossa” experimental campaign and model updating for numerical damage evaluation
COMPDYN Proceedings
Autore/i: Salachoris, GEORGIOS PANAGIOTIS; Magagnini, E.; Clementi, F.
Editore: National Technical University of Athens
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This paper outlines the characterization of masonry walls composed of “Scaglia Rossa”, a typical stone of the Apennine area between the Umbria and Marche Regions in Central Italy. The study focuses the assessment of the mechanical behavior by means of an experimental campaign carried out in the laboratory of the Polytechnic University of Marche, where the samples of “Scaglia Rossa” masonry, obtained from the controlled demolition of three school buildings, were reconstructed with the same techniques of the 1950s-'60s, and then tested in order to identify both the constituent materials, stone and mortar, and the composite masonry. The experimental tests were prior to a numerical analysis implemented by the adoption of a nonlinear model capturing the cracking behavior. The main mechanical parameters were then calibrated by means of an optimization algorithm of Levenberg-Marquardt, considering a continuous approach in macro-modelling techniques and obtaining resistance parameters not deriving directly from the experimental tests. The comparison between the results obtained from the Levenberg - Marquardt algorithm by changing the parameters of the damage model based on data given by the experimental campaign allowed to confirm the validity of the approach used.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/293921

Continuous and discontinuous descriptions of blocked structures: The case study of Santissimo Crocifisso Church in Pretare (Italy)
COMPDYN Proceedings
Autore/i: Clementi, F.; Ferrante, A.; Giordano, E.; Lenci, S.
Editore: National Technical University of Athens
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Advanced numerical modelling of the masonry “Apennine Church” of Santissimo Crocifisso in Pretare, Arquata del Tronto (AP), was here utilized to have an insight into the dynamic properties and behavior of the structure under strong nonlinear dynamic excitations. The objectives were achieved by comparing nonlinear dynamic analyses through discontinuous and continuous approaches. In the discrete element approach, the Non-Smooth Contact Dynamics method, implemented in LMGC90©, was applied, adopting a full 3D detailed discretization. The Church was schematized as an arrangement of discrete rigid blocks, subjected to sliding by friction and perfect plastic collisions, governed by Signorini's impenetrability condition and dry-friction Coulomb's law, with a null restitution coefficient. In the finite element approach, the Concrete Damaged Plasticity model available in Midas FEA NX© was involved. This model allows reproducing the tensile cracking, the compressive crushing, and the degradation of the material under cyclic loads. At the end, the structure exhibited a complex dynamic behavior, because of the geometrical nonlinearity and the non-smooth nature of the contact laws. Finally, the numerical analyses provided a valuable picture of the actual behavior of the church, which is mandatory for future strengthening interventions.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/293922

Structural Health Monitoring of Architectural Heritage: From the past to the Future Advances
INTERNATIONAL JOURNAL OF ARCHITECTURAL HERITAGE
Autore/i: Clementi, Francesco; Formisano, Antonio; Milani, Gabriele; Ubertini, Filippo
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287607

DEM analysis of the effect of bond pattern on the load bearing capacity of barrel vaults under vertical loads
INTERNATIONAL JOURNAL OF MASONRY RESEARCH AND INNOVATION
Autore/i: Chen, S.; Ferrante, A.; Clementi, F.; Bagi, K.
Classificazione: 1 Contributo su Rivista
Abstract: Bond patterns influence responses of masonry barrel vaults to mechanical loads. In this research, the discrete element method (DEM) was applied to investigate how bond patterns affect the static load bearing capacity of barrel vaults under vertical loads. The two most widely-used bond patterns (transverse and longitudinal) were studied. Using a commercial DEM software, 3DEC, vaults with different angles of embrace were prepared according to both patterns, and then loaded in three alternative ways until failure. The failure loads were recorded, and compared for the two alternative patterns of each overall geometry. Two competing effects were found: 1) in transversal vaults the arches work nearly independently of each other which decreases the load resistance in comparison to longitudinal vaults; 2) larger size of the voussoirs along the arch direction increases the load bearing.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/291452

Failure Analysis of Apennine Masonry Churches Severely Damaged during the 2016 Central Italy Seismic Sequence
BUILDINGS
Autore/i: Clementi, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: This paper presents a detailed study of the damages and collapses suffered by various masonry churches in the aftermath of the seismic sequence of Central Italy in 2016. The damages will first be analyzed and then compared with the numerical data obtained through 3D simulations with eigenfrequency and then nonlinear static analyses (i.e., pushover). The main purposes of this study are: (i) to create an adequately consistent sensitivity study on several definite case studies to obtain an insight into the role played by geometry—which is always unique when referred to churches—and by irregularities; (ii) validate or address the applicability limits of the more widespread nonlinear approach, widely recommended by the Italian Technical Regulations. Pushover analyses are conducted assuming that the masonry behaves as a nonlinear material with different tensile and compressive strengths. The consistent number of case studies investigated will show how conventional static approaches can identify, albeit in a qualitative way, the most critical macro-elements that usually trigger both global and local collapses, underlining once again how the phenomena are affected by the geometry of stones and bricks, the texture of the wall face, and irregularities in the plan and elevation and in addition to hypotheses made on the continuity between orthogonal walls.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287749

Influence of local site effects on the typological fragility curves for class-oriented masonry buildings in aggregate condition
THE OPEN CIVIL ENGINEERING JOURNAL
Autore/i: Formisano, A.; Chieffo, N.; Clementi, F.; Mosoarca, M.
Classificazione: 1 Contributo su Rivista
Abstract: Background: The Municipality of Baranello, located in the province of Campobasso, is considered as a reference case study for implementing a systematic procedure for the assessment of local site effects. The territory is characterised by a heterogeneous soil, made of a basal interval formed in large part by outcrops found along with the middle-basal bands of the local slopes, which is particularly sensitive to geo-hazard effects. Aims: The present work aims to investigate the influence of local site effects on the seismic vulnerability of an oriented-class of masonry building compounds. The historical buildings surveyed are mainly made up of rough stone masonry, particularly vulnerable to seismic phenomena. The buildings are appropriately grouped in typological classes based on the CARTIS form and then subdivided into different categories according to the EMS-98 scale based on their geometrical and structural characteristics. Methods: The performed vulnerability analysis is based on a vulnerability-index method conceived for buildings grouped in aggregate condition. Moreover, the expected damage scenario is properly evaluated based on a specific attenuation law to take into consideration the effect produced by a reference scenario event. Furthermore, the local site conditions have been evaluated based on a 1D half space approach in order to predict the possible increment of the expected damage due to the soil stratigraphy. Results: The local site conditions provide a global increment of the expected vulnerability of 33% with respect to the case in which the geo-hazard effects are neglected. In this activity framework, typological fragility curves are derived for comparing the exceeding probability thresholds for the examined building classes. Conclusion: The proposed research represents an important starting point for large-scale vulnerability assessment since it provides a simplified and comprehensive method for predicting seismic damage scenarios of historic center considering local site effects.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/290709

Mechanical characterization of “Scaglia Rossa” stone masonry through experimental and numerical analyses
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Salachoris, GEORGIOS PANAGIOTIS; Magagnini, E.; Clementi, F.
Classificazione: 1 Contributo su Rivista
Abstract: This paper outlines the complete characterization of masonry walls composed of “Scaglia Rossa”, a typical stone of the Apennine area between the Umbria and Marche Regions in Central Italy. The study focuses the assessment of the mechanical behavior by means of an experimental campaign carried out in the laboratory of the Polytechnic University of Marche, where the samples of “Scaglia Rossa” masonry, obtained from the controlled demolition of three school buildings, were reconstructed with the same techniques of the 1950s-‘60s, and then tested in order to identify both the constituent materials, stone and mortar, and the composite masonry. The experimental tests were prior to a numerical analysis implemented by the adoption of a nonlinear model capturing the cracking behavior. The main mechanical parameters were then calibrated by means of an optimization algorithm of Levenberg-Marquardt, considering a continuous approach with both (i) macro- and (ii) micro-modelling techniques and obtaining resistance parameters not deriving directly from the experimental tests. The comparison between the results obtained from the Levenberg - Marquardt algorithm by changing the parameters of the damage model based on data given by the experimental campaign allowed to confirm the validity of the approach used.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/291690

Unreinforced and TRM-Reinforced Masonry Building Subjected to Pseudodynamic Excitations: Numerical and Experimental Insights
JOURNAL OF ENGINEERING MECHANICS
Autore/i: Giordano, Ersilia; Bertolesi, Elisa; Clementi, Francesco; Buitrago, Manuel; Adam, José M.; Ivorra, Salvador
Classificazione: 1 Contributo su Rivista
Abstract: This paper contains a numerical study based on tests carried out at the Universitat Politècnica de València (Spain) on a U-shaped unreinforced and Textile Reinforced Mortar (TRM)-reinforced masonry structure subjected to horizontal loads. The masonry was composed of clay bricks with 10 mm thick mortar joints arranged in an English bond pattern. The prototype was tested by applying pseudodynamic displacement-driven cycles and varying cyclic amplitudes and frequencies in two different stages: (1) on the as-built structure and (2) after the application of the TRM material. A series of nonlinear numerical simulations were performed adopting the ABAQUS/Explicit version 6.14 finite-element (FE) software. The FE calibration was carried out using the results obtained during ambient vibration tests. Simulations were then used to evaluate the effectiveness of the proposed TRM strengthening technique in improving the behaviour of low-rise old masonry building subjected to horizontal loads.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/292270

Natural Frequencies And Internal Resonance Of Beams With Arbitrarily Distributed Axial Loads
JOURNAL OF APPLIED AND COMPUTATIONAL MECHANICS
Autore/i: Lenci, S.; Clementi, F.
Classificazione: 1 Contributo su Rivista
Abstract: An exact analytical solution for transversal free vibrations of a beam subjected to an arbitrary distributed axial load and a tip tension is obtained by means of a power series representation, whose coefficients are determined recursively in an easy way. The dependence on the natural frequencies on the load is then investigated, and the buckling load (corresponding to vanishing frequency) is also discussed. Next, the 1:3 internal resonance between the first and the second mode is deeply studied, and an interesting (and unexpected) property is found for linearly distributed axial loads
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/291395

Influence of Stereotomy on Discrete Approaches Applied to an Ancient Church in Muccia, Italy
JOURNAL OF ENGINEERING MECHANICS
Autore/i: Ferrante, A.; Schiavoni, M.; Bianconi, F.; Milani, G.; Clementi, F.
Classificazione: 1 Contributo su Rivista
Abstract: This work evaluated the remarkable influence of stereotomy on discrete methods adopted for the dynamic response of an ancient masonry structure. The historic building used as a case study is the Church of Santa Maria of Varano in Muccia, in the province of Macerata, Italy, which was exposed to the severe seismic sequence that hit Central Italy in 2016, namely the major events of Accumoli, Visso, and Norcia. The structure was modeled using the actual stereotomy of blocks and three hypothetical arrangements of blocks of the masonry walls to investigate the existing crack pattern and vulnerabilities of the church. Sensitivity analyses were performed using the nonsmooth contact dynamics and discrete-element methods. These novel approaches suitably reproduced complex behaviors, considering large displacements and complete block separations, which is useful for upcoming retrofitting works.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/292100

Model Updating of Historical Belfries Based on Oma Identification Techniques
INTERNATIONAL JOURNAL OF ARCHITECTURAL HERITAGE
Autore/i: Standoli, G.; Giordano, E.; Milani, G.; Clementi, F.
Classificazione: 1 Contributo su Rivista
Abstract: Central Italy Earthquakes occurred in 2016 pointed out once more the vulnerability of Cultural Heritage (CH), especially for what concerns bell-towers since they tend to get dramatically damaged due to their considerable slenderness and deterioration, endangering their surroundings and making their preservation fundamental. This work presents the results of the study carried out on four different isolated masonry bell towers, located in Ferrara province (Italy); the parameters of the materials were deduced by calibrating Finite Element Models (FEMs) using the data collected during an investigation campaign conducted with a wired accelerometric sensor system, since it was not possible to apply destructive methodologies. Dynamic data were extracted through the application of two Operational Modal Analysis (OMA) identification techniques: the Enhanced Frequency Domain Decomposition (EFDD) and the Stochastic Subspace Identification (SSI) methodology. Particular attention was devoted to the use of MAC matrix in the validation of the mode shapes results.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/274078

Discontinuous approaches for nonlinear dynamic analyses of an ancient masonry tower
ENGINEERING STRUCTURES
Autore/i: Ferrante, A.; Loverdos, D.; Clementi, F.; Milani, G.; Formisano, A.; Lenci, S.; Sarhosis, V.
Classificazione: 1 Contributo su Rivista
Abstract: The aim of this paper is to present the development of discontinuous approaches to simulate the nonlinear dynamic behaviour of the civic clock tower of Rotella, in the province of Ascoli Piceno (Italy). The study involves the use of the Non-Smooth Contact Dynamics method implemented in the LMGC90© code, where sliding motions are governed by Signorini's impenetrability condition and dry-friction Coulomb's law, and the Discrete Element Method with cohesive and tensional behaviours at the joints in the 3DEC© code. The tower was represented using three different geometric models ranged from the most complex one, including the full geometry and multi-leaf masonry walls, to the simplest one, including the single-leaf walls as a simplification of the real masonry. The numerical results highlighted the modes of failure depending on the shape, size and texture of the masonry and the modalities of progressive damage under dynamic actions. Moreover, both numerical approaches have proven to be capable of simulating large displacements and complete block separations, reproducing complex mechanical behaviours and making predictions on the vulnerability assessment of the historical masonry buildings.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/286753

FE vs. DE modeling for the nonlinear dynamics of a historic church in central Italy
GEOSCIENCES
Autore/i: Ferrante, A.; Giordano, E.; Clementi, F.; Milani, G.; Formisano, A.
Classificazione: 1 Contributo su Rivista
Abstract: The present research paper properly focuses on the dynamics and failure mechanisms of the masonry “Apennine Church” of Santissimo Crocifisso in Pretare, municipality of Arquata del Tronto in the province of Ascoli Piceno (Marche region, Central Italy). Such a peculiar structural type traditionally characterizes the intense seismic area of Central Italy, unfortunately almost totally damaged by the recent shock sequence of 2016. Advanced numerical modeling through discontinuous and continuous approaches were here utilized to have an insight into the dynamic properties and behavior of the structure under strong nonlinear dynamic excitations. In the discrete element approach, the non-smooth contact dynamics method, implemented in LMGC90©, was applied, adopting a full 3D detailed discretization. The church was schematized as an arrangement of rigid blocks, subjected to sliding by friction and perfect plastic collisions, with a null restitution coefficient. In the finite element approach, the concrete damaged plasticity model available in Midas FEA NX© was involved. This model allows reproducing the tensile cracking, the compressive crushing, and the degradation of the material under cyclic loads. Finally, the numerical analyses provided a valuable picture of the actual behavior of the church, thus giving useful hints for future strengthening interventions.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/290380

An experimental and numerical study on the in-plane axial and shear behavior of sprayed in-situ concrete sandwich panels
ENGINEERING STRUCTURES
Autore/i: Serpilli, Michele; Clementi, Francesco; Lenci, Stefano
Classificazione: 1 Contributo su Rivista
Abstract: The pa­per deals with the ex­per­i­men­tal and nu­mer­i­cal char­ac­ter­i­za­tion of the in-plane ax­ial and shear me­chan­i­cal be­hav­ior of sprayed in-situ re­in­forced con­crete (RC) sand­wich pan­els, used as struc­tural walls. Ax­ial com­pres­sion tests were car­ried out on spec­i­mens with dif­fer­ent slen­der­ness ra­tios to study their be­hav­ior un­der ax­ial ver­ti­cal loads. While the di­ag­o­nal com­pres­sion test and shear load with con­stant com­pres­sion test were re­spec­tively per­formed on squared pan­els, an­a­lyz­ing their re­sponse to in-plane hor­i­zon­tal lat­eral forces. Ul­ti­mate ax­ial and shear loads have been ex­per­i­men­tally de­ter­mined and the most sig­nif­i­cant load–dis­place­ment di­a­grams have been re­ported. The ob­tained re­sults have been com­pared with other ex­per­i­men­tal cam­paigns on RC sand­wich pan­els and with con­ven­tional RC walls equa­tions, avail­able in codes of prac­tice and lit­er­a­ture. The struc­tural po­ten­tial­i­ties of RC sand­wich pan­els as load-bear­ing and shear walls are high­lighted. The ex­per­i­men­tal in­ves­ti­ga­tion is cor­rob­o­rated by a 3D non­lin­ear fi­nite el­e­ment (FE) nu­mer­i­cal analy­sis, con­sid­er­ing the in­flu­ence of the in­su­la­tion layer, the ef­fi­ciency of steel con­nec­tors, and the in­volved ma­te­r­ial non­lin­ear­i­ties.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287329

Advanced Seismic Assessment of Four Masonry Bell Towers in Italy after Operation Modal Analysis (OMA) Identification
INTERNATIONAL JOURNAL OF ARCHITECTURAL HERITAGE
Autore/i: Milani, G.; Clementi, F.
Classificazione: 1 Contributo su Rivista
Abstract: The paper presents an advanced seismic assessment of four masonry bell towers located in Northern Italy based on detailed 3D FE models on which elastic parameters were previously identified by operational modal analysis. The numerical assessment includes a preliminary identification of the elastic moduli of the different volumes of each tower made by means of a fast-micro-GA approach. After proper identification of the main four eigenfrequencies, non-linear static (pushover) and full non-linear dynamic analyses are performed adopting a material model for masonry which is characterized by softening and two distinct damage parameters in both tension and compression. The results obtained with non-linear static and non-linear dynamic analyses in all the simulations performed exhibit a satisfactory match, suggesting similar conclusions in terms of general dynamic response and seismic vulnerability of the towers.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/272648

Miglioramento sismico della scuola “Puccini” in Senigallia. Dalla diagnosi all’intervento
MODULO
Autore/i: Quagliarini, E; Lenci, S; Clementi, F; Maracchini, G; Monni, F
Classificazione: 1 Contributo su Rivista
Abstract: Questo articolo riporta l'esperienza dell'intervento progettato ed eseguito sull'edificio scolastico "Puccini" in Seni­gallia, il quale presenta caratteristiche architettoniche e vulnerabilità sismiche tipiche di edifici scolastici costruiti in I­talia nel secondo dopoguerra. La scuola, insieme ad altre localizzate sempre nel Comune di Senigallia, ed aventi carat­teristiche simili a livello di materiali e tecnologia costruttiva, è stata oggetto di studio ed analisi approfondite nell'ambi­to della convenzione di ricerca scienti­fica stipulata tra l'Università Politecnica delle Marche e il Comune di Senigallia inerente ''La valutazione e la stesura di linee guida per la riduzione del rischio sismico dell'edilizia scolastica del dopo guerra".
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/294383

The Non-smooth Dynamics of Multiple Leaf Masonry Walls of the Arquata Del Tronto Fortress
Proceedings of XXIV AIMETA Conference 2019
Autore/i: Clementi, Francesco; Ferrante, Angela; Lenci, Stefano
Editore: Springer
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The progressive damage of the multiple leaf masonry walls of the Arquata del Tronto medieval fortress, inside the epicentral zone of the last Centre Italy earthquakes of August and October 2016, has been investigated by means of the Non-Smooth Contact Dynamics method (NSCD). According to this model, the masonry structure has been modelled as a system of rigid blocks, and since the contacts between blocks are governed by the Signorini’s impenetrability condition and by dry-friction Coulomb’s law, the building exhibits discontinuous dynamics. The NSCD method has proved to be a powerful tool for investigating the dynamics induced by ground seismic accelerations. Indeed, the numerical results have given a deep insight into the seismic vulnerability of this damaged medieval fortress, confirming several possible failure mechanisms.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/275745

Damage assessment of churches in the city of camerino after the 2016 central Italy seismic sequence
Proceedings of the International Conference on Structural Dynamic , EURODYN
Autore/i: Giordano, E.; Ferrante, A.; Clementi, F.; Lenci, S.
Editore: European Association for Structural Dynamics
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In the present work, the importance of considering the exact nonlinear and three-dimensional behavior of masonry structures is shown, in order to highlight all the structural deficiencies of different churches damaged by the last Centre Italy earthquake in the city of Camerino. For this purpose, the exact geometries of the structures are reconstructed, while information regarding the mechanical properties of masonry material are derived from previous investigations and literature references. Based on this information, different numerical models are used to reconstruct the damages. Different three-dimensional FE models, endowed with an elastic plastic (softening) damage constitutive law, are adopted to determine the seismic vulnerability of the building by means of nonlinear static analyses using the smeared fracture energy approach. With this method it is possible to establish, with a right degree of approximation, the areas where the most important cracks are expected and, in general, the location of the potential damage caused by horizontal forces.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287433

Tracking modal parameter evolution ofdifferent cultural heritage structures damaged by central Italy earthquake of 2016
AIP Conference Proceedings
Autore/i: Ribilotta, E.; Giordano, E.; Ferrante, A.; Clementi, F.; Lenci, S.
Editore: American Institute of Physics Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The preliminary results of an ambient-vibration based investigation conducted on a large sample of historic masonry towers in the Marche region (Central Italy) are presented, with a focus on the belfry of Collegiata of Santa Maria in Visso (Italy). The assessment procedure includes full-scale ambient vibration testing, ambient modal identification, finite element modeling and dynamic-based identification of the uncertain structural parameters of the model. As the most doubtful parameters, the modulus of elasticity of the masonry is adjusted to achieve the experimental results with numerical model by simple operations.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287430

Modal parameters identification on environmental testd of ancient bell towers and validation of their numerical models
Proceedings of the International Conference on Structural Dynamic , EURODYN
Autore/i: Clementi, F.; Standoli, G.; Giordano, E.; Ferrante, A.; Lenci, S.
Editore: European Association for Structural Dynamics
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Masonry towers are quite widespread in Europe and represent an important portion of the built heritage that must be preserved, especially in high-seismicity regions. Very often, such masonry towers exhibit unique peculiar morphologic and typological characteristics, which might affect their different structural behaviors under horizontal loads. For this reason, accurate knowledge of their dynamical parameters is useful for seismic assessment and the design of risk mitigation interventions. In this work, the opportunities provided by dynamic identification techniques for the non-destructive evaluation of heritage structures are discussed with a focus on different bell towers, located in the Marche region (Italy). All of them were stricken by a long seismic sequence (Center Italy earthquakes between August and October 2016), and are investigated in detail in order to have an insight into their dynamic behavior. Furthermore, the experimental investigations and the operational modal analysis results are presented, and they are useful for defining the Finite Element (FE) model of the towers with a continuum approach. The monitoring system consists of several elements adequately connected. Many operative problems have conditioned the positioning of the instrumentation due to the limited accessibility of the structure, not only to the primary access but also to reach the top. However, it has been possible to identify with certain confidence the first three frequencies of the towers and their corresponding mode shapes. The results carried out after the updating procedure may be considered very good. The material data values estimated in this way will constitute an important reference for the evaluation of the state of the building.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287434

Damage assessment of san francesco church in amandola hit by central Italy 2016-2017 seismic event
AIP Conference Proceedings
Autore/i: Giordano, E.; Ferrante, A.; Ribilotta, E.; Clementi, F.; Lenci, S.
Editore: American Institute of Physics Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Italy is a high seismic risk country. Since 1900 more than 30 earthquakes with magnitude greater than Mw=5.8 occurred, and the last one is the Central Italy seismic sequence. The first shock aroused in the 24th August (Mw=6.2) followed by another stronger quake in the 30th October (Mw=6.5). It heavily hit the regions of Marche, Umbria, and Abruzzo causing many deaths, injuries and extensive damages on the cultural heritage. This paper analyses the church of San Francesco in Amadola, located in the Marche region that has been considered condemned for the severe damages reported after these earthquakes. The church is globally analyzed by the application of nonlinear static analysis on a Finite Element Model where the nonlinearity of masonry is taking into account with a proper constitutive law. The study wants to prove how global analysis combined by the local analysis can reproduce the behavior of this structure during a quake, showing that it can repeat the real damages produced by earthquakes.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287432

A Genetic Algorithm Procedure for the Automatic Updating of FEM Based on Ambient Vibration Tests
SENSORS
Autore/i: Bianconi, F.; Salachoris, G. P.; Clementi, F.; Lenci, S.
Classificazione: 1 Contributo su Rivista
Abstract: The dynamic identification of the modal parameters of a structure, in order to gain control of its functionality under operating conditions, is currently under discussion from a scientific and technical point of views. The experimental observations obtained through structural health monitoring (SHM) are a useful calibration reference of numerical models (NMs). In this paper, the procedures for the identification of modal parameters in historical bell towers using a stochastic subspace identification (SSI) algorithm are presented. Then, NMs are manually calibrated on the identification’s results. Finally, the applicability of a genetic algorithm for the automatic calibration of the elastic parameters is considered with the aim of searching for the properties of the autochthonous material, in order to reduce modelling error following the model assurance criterion (MAC). In this regard, several material values on the same model are examined to see how to approach the evolution and the distribution of these features, comparing the characterization proposed by the genetic algorithm with the results considered by the manual iterative procedure.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/282515

Advanced seismic analyses of "Apennine churches" stroked by the central Italy earthquakes of 2016 by the non-smooth contact dynamics method
AIP Conference Proceedings
Autore/i: Ferrante, A.; Ribilotta, E.; Giordano, E.; Clementi, F.; Lenci, S.
Editore: American Institute of Physics Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The dynamic behaviour and the seismic vulnerability of different masonry "Apennine Churches". dramatically damaged by the last shocks sequence of 2016 that occurred in Central Italy, have been studied in this paper by means of advanced 3D numerical analyses with the Discrete Element Method (DEM). Thus, a discontinuous approach has been used to assess the dynamic properties and the vulnerability of the masonry structure, through large deformations regulated by the Signorini's law, concerning the impenetrability between the rigid bodies, and by the Coulomb's law, regarding the dry-friction model. The major purpose of this study is to highlight that relevant data on the real structural behaviour of historical masonry can be provided through advanced numerical analyses. The comparison between the results of the numerical simulation and the survey of the existing crack pattern of the churches permitted to validate the used approach. Finally, from the results and conclusions of these cases study, it is possible to affirm that the used methodology can be applied to a wide variety of historical masonry structure in Europe.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287431

Expeditious damage index for arched structures based on dynamic identification testing
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Giordano, E.; Mendes, N.; Masciotta, M. G.; Clementi, F.; Sadeghi, N. H.; Silva, R. A.; Oliveira, D. V.
Classificazione: 1 Contributo su Rivista
Abstract: This paper presents a new damage detection index for arched structures, which can easily and quickly provide an estimate of their integrity. The results from eight laboratory tests performed on both reinforced and unreinforced adobe arches are used to define the index. The arches are damaged up to collapse using pseudo-static test cycles carried out by applying progressive controlled displacements at third span. The test records allow to follow the stiffness degradation of each arch by plotting the relative force–displacement curves, as well as to track their frequencies variation during the damage evolution by means of dynamic identification tests performed at the end of each cycle. The new index considers the bending moment as the main cause of damage for the analysed arches; therefore, starting from the bending stiffness, a damage indicator was developed and experimentally validated, as function of the frequency reduction, respect to the undamaged scenario. Finally, the index is also validated for different types of arch collapse mechanisms through Finite Element Modelling.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/283436

Static and dynamic testing of highway bridges: a best practice example
JOURNAL OF CIVIL STRUCTURAL HEALTH MONITORING
Autore/i: Marcheggiani, L.; Clementi, F.; Formisano, A.
Classificazione: 1 Contributo su Rivista
Abstract: The load bearing capacity of a viaduct and its structural behaviour under traffic or seismic excitation can be evaluated using well-established modelling methods aided by computing facilities of great capability. However, to ensure reliable results, numerical models used in designing should be calibrated with accurate information on material properties and structural components. The static and dynamic testing procedures applied to a multi-span bridge along a new highway link inaugurated in 2014 in northern Italy are examined as a best practice example. The structural responses and performances are compared with and evaluated in the light of static and dynamic load test results. In particular, Operational Modal Analysis and Experimental Modal Analysis are used and compared to match with the numerical model. The comparison showed that the dynamic load test can supplement the static load test for the structural evaluation of new viaducts; it may also be taken as an alternative for the monitoring of operational viaducts.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/272569

1:1 internal resonance in a two d.o.f. complete system: a comprehensive analysis and its possible exploitation for design
MECCANICA
Autore/i: Clementi, F.; Lenci, S.; Rega, G.
Classificazione: 1 Contributo su Rivista
Abstract: The internal resonance of a two degree-of-freedom mechanical system with all typical (quadratic and cubic) geometric nonlinearities is studied, limiting to the case of free dynamics. The Multiple Time Scale method is used to provide an analytical, closed form, approximation of the backbone curves. The cornucopia of different possible behaviours that can been obtained by varying the nonlinear stiffnesses is discussed in depth, illustrating them with some examples and verifying with numerical simulations. Some partially unexpected or relevant behaviours are highlighted, and some hints on how to exploit the proposed results to design nonlinearly tailored systems are given.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/280902

Aftershock fragility assessment of Italian cast–IN–place RC industrial structures with precast vaults
JOURNAL OF BUILDING ENGINEERING
Autore/i: Poiani, Marina; Gazzani, Valentina; Clementi, Francesco; Lenci, Stefano
Classificazione: 1 Contributo su Rivista
Abstract: Through a fragility analysis carried out with different probabilistic methods, the vulnerability of an Italian cast-in-place RC industrial structure with precast reinforced hollow brick light-weight vaults is evaluated via nonlinear analyses. After a brief description of the vault construction system, a typical case study built in the 1960s is considered and the influence of FE numerical modelling through three different representations of the vault system is assessed. Fragility curves are calculated by Incremental Dynamic Analysis (IDA), with three damage limit threshold values corresponding to local limit conditions regarding bending or shear that first occur in a few elements, as determined through pushover analyses. A comparison of fragility curves in the two horizontal directions (X–Y) for the three models is reported. Concerning the model with the greatest probability of collapse, seismic sequence effects on structural damage with the same ground motions for mainshock and aftershock are taken into account. Double Incremental Dynamic Analysis (D-IDA), with the mainshock represented by several fixed percentages of Near Collapse PGAs previously evaluated in X–Y directions and scaled aftershocks, is performed and compared to the IDA results. Aftershock fragility curves created with only the damage limit threshold value of Near Collapse are likened to the case that analyses a single seismic event (undamaged structure). Furthermore, ductility damage indices are calculated for maximum displacements obtained by each nonlinear dynamic analysis of IDA and D-IDA.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/273195

Flexural wave propagation in infinite beams on a unilateral elastic foundation
NONLINEAR DYNAMICS
Autore/i: Lenci, S.; Clementi, F.
Classificazione: 1 Contributo su Rivista
Abstract: The problem of flexural wave propagation on a beam resting on a unilateral elastic substrate is addressed. The Euler–Bernoulli beam theory, which is valid for slender beams and for large enough wave length, is used. The governing equations are recalled, and the boundary conditions corresponding to the “single wave” periodic solutions are determined. The ensuing system of three algebraic transcendental equations is solved, and the exact solution of the problem is provided, in spite of the nonlinearity due to the piecewise behavior of the soil. The wave velocity as function of the foundation stiffness is obtained and compared with the classical case of the bilateral foundation. The main wave propagation properties are discussed, and some of them are illustrated with graphs reporting wave shapes.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/265852

Seismic analysis and retrofitting of civil engineering structures
AIP Conference Proceedings
Autore/i: Clementi, F.; Formisano, A.; Milani, G.; Mosoarca, M.
Editore: American Institute of Physics Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287429

Crumbling of Amatrice clock tower during 2016 Central Italy seismic sequence: Advanced numerical insights
FRATTURA E INTEGRITÀ STRUTTURALE
Autore/i: Clementi, F.; Milani, G.; Ferrante, A.; Valente, M.; Lenci, S.
Classificazione: 1 Contributo su Rivista
Abstract: The dynamic behaviour and the seismic vulnerability of the ancient civic tower of Amatrice, dramatically damaged by the last shocks sequence of 2016 that occurred in Central Italy, have been studied in this paper by means of advanced 3D numerical analyses with the Discrete Element Method (DEM). Thus, a discontinuous approach has been used to assess the dynamic properties and the vulnerability of the masonry structure, through large deformations regulated by the Signorini’s law, concerning the impenetrability between the rigid bodies, and by the Coulomb’s law, regarding the dry-friction model. Afterward, different values have been assigned to the friction coefficient of the models and real seismic shocks have been applied in the nonlinear analyses. The major purpose of this study is to highlight that relevant data on the real structural behaviour of historical masonry can be provided through advanced numerical analyses. The comparison between the results of the numerical simulation and the survey of the existing crack pattern of the bell tower permitted to validate the approach used. Finally, from the results and conclusions of this case study, it is possible to affirm that the used methodology can be applied to a wide variety of historical masonry structure in Europe.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/272571

The modelling of multiple leaf masonry walls of the arquata del tronto fortress as a non-smooth dynamical system
Proceedings of the International Conference on Structural Dynamic , EURODYN
Autore/i: Ferrante, A.; Giordano, E.; Clementi, F.; Sarhosis, V.; Milani, G.; Lenci, S.
Editore: European Association for Structural Dynamics
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In the present paper has been reported the Non-Smooth Contact Dynamics method (NSCD) used for the damage evaluation of the multiple leaf masonry walls of the medieval fortress of Arquata del Tronto, strongly affected by the last Centre Italy earthquakes of August and October 2016. Pursuing this approach, a system of rigid blocks has been used for the assembly of the masonry structure. By means of contacts between blocks, which are governed by the Signorini's impenetrability condition and by dry-friction Coulomb's law, the building exhibits discontinuous dynamics. Finally, the NSCD method has proved to be an effective instrument for investigating the dynamical behaviour of the masonry structures under the ground seismic accelerations. Indeed, several possible failure mechanisms have been confirmed through the numerical results, which have given a deep insight into the seismic vulnerability of this damaged medieval fortress.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287437

Advanced numerical analyses by the Non‐Smooth Contact Dynamics method of an ancient masonry bell tower
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
Autore/i: Ferrante, A.; Clementi, F.; Milani, G.
Classificazione: 1 Contributo su Rivista
Abstract: Advanced numerical analyses were carried out in order to assess the nonlinear dynamical behaviour of the bell tower of Pomposa Abbey in Codigoro, in the province of Ferrara (Italy), by means of the Non‐Smooth Contact Dynamics (NSCD) method. The main purpose of the work is to investigate the capacity of the main mechanical parameter used in the analyses, namely, the friction coefficient, to have effects on the mechanical response of ancient masonry structures undergoing seismic actions. Therefore, the tower was modelled following the discrete element method (DEM) and assembling the masonry texture as rigid bodies tied by frictional joints. Thus a discontinuous approach was used to assess the dynamic properties and the vulnerability of the masonry structure, through large deformations regulated by the Signorini's law, concerning the impenetrability between the rigid bodies; and by the Coulomb's law, regarding the dry‐friction model. Afterward, different values were assigned to the friction coefficient of the models, and a variety of real seismic shocks have been applied in the nonlinear analyses. Finally, it is possible to see different failure mechanisms resulting for each friction value and types of dynamic actions used, as expected.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/273439

Effectiveness of textile reinforced mortar (TRM) materials in preventing seismic-induced damage in a U-shaped masonry structure submitted to pseudo-dynamic excitations
CONSTRUCTION AND BUILDING MATERIALS
Autore/i: Bertolesi, E.; Buitrago, M.; Giordano, E.; Calderón, P. A.; Moragues, J. J.; Clementi, F.; Adam, J. M.
Classificazione: 1 Contributo su Rivista
Abstract: This paper presents the experimental results obtained from tests on a 2/3 scale U-shaped masonry building constructed in one of the ICITECH laboratories at the Universitat Politècnica de València (Spain). The prototype measured 3.31 × 4.19 m2 by 2.15 m high and had a wall thickness of 230 mm. The masonry was composed of 230 × 110 × 50 mm3 solid clay bricks with approximately 10 mm-thick mortar joints arranged in English bond. The tests were aimed at evaluating the effectiveness of cement-based reinforcing materials (Textile Reinforced Mortar) applied to weak masonry substrates severely damaged by horizontal loads such as those induced by a seismic event. The tests were carried out in three phases: (i) testing of the as-built structure, (ii) application of one external layer of TRM to restore the masonry’s original load-bearing capacity and then (iii) testing the TRM-strengthened structure. Dynamic behaviour was monitored by both traditional and fibre optic sensors (FO), including 28 Linear Variable Displacement Transducers (LVDTs) and 3 long-gauge optical sensors. Strengthening effectiveness was evaluated by several parameters: hysteretic curves, strength degradation, computed cumulative energy dissipation and cracking mechanisms. TRM reinforcement was shown to significantly extend the load-bearing and displacement capacity of the masonry prototype, reducing seismic-induced damage applied by pseudo-dynamic excitation, although it had a limited effect on cumulative energy dissipation.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/275311

Damage assessment of ancient masonry churches stroked by the Central Italy earthquakes of 2016 by the non-smooth contact dynamics method
BULLETIN OF EARTHQUAKE ENGINEERING
Autore/i: Clementi, F.; Ferrante, A.; Giordano, E.; Dubois, F.; Lenci, S.
Classificazione: 1 Contributo su Rivista
Abstract: The non-smooth contact dynamics method was selected to investigate the damage occurred to typical masonry churches (namely Apennine churches) belonging to Central Italy areas affected by the seismic activity started in 2016. The investigated buildings show discontinuous dynamics since the optioned method gave the chance to properly model the temples as multi rigid body systems using the Signorini’s impenetrability condition and the dry-friction Coulomb’s law, achieving a thoughtful response to ground seismic solicitations. The results provided by the assessment grant an overview of the most common damages and failure mechanisms, giving the guidelines to restoration projects that fully respond to structural needs.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/264833

Longitudinal–transversal internal resonances in Timoshenko beams with an axial elastic boundary condition
NONLINEAR DYNAMICS
Autore/i: Lenci, S.; Clementi, F.; Kloda, L.; Warminski, J.; Rega, G.
Classificazione: 1 Contributo su Rivista
Abstract: The internal resonances between the longitudinal and transversal oscillations of a forced Timoshenko beam with an axial end spring are studied in depth. In the linear regime, the loci of occurrence of 1 : ir, ir∈ N, internal resonances in the parameters space are identified. Then, by means of the multiple time scales method, the 1 : 2 case is investigated in the nonlinear regime, and the frequency response functions and backbone curves are obtained analytically, and investigated thoroughly. They are also compared with finite element numerical simulations, to prove their reliability. Attention is paid to the system response obtained by varying the stiffness of the end spring, and it is shown that the nonlinear behaviour instantaneously jumps from hardening to softening by crossing the exact internal resonance value, in contrast to the singular (i.e. tending to infinity) behaviour of the nonlinear correction coefficient previously observed (without properly taking the internal resonance into account).
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/283809

The non-smooth story of different masonry towers damaged by the central Italy seismic sequence of 2016
COMPDYN 2019 Proceedings
Autore/i: Clementi, F.; Ferrante, A.; Giordano, E.; Lenci, S.
Editore: National Technical University of Athens
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The Non-Smooth Contact Dynamics method (NSCD) has been applied to the study of the seismic response of different belfries inside the epicentral zone of the last Centre Italy earthquakes of August and October 2016. According to this model, the masonry towers have been modelled as a system of rigid blocks, and since the contacts between blocks are governed by the Signorini's impenetrability condition and by dry-friction Coulomb's law, the towers exhibit discontinuous dynamics. The NSCD method has proved to be a powerful tool for investigating the dynamics induced by ground seismic accelerations. Indeed, the numerical results have given a deep insight into the seismic vulnerability of these damaged towers, confirming several possible failure mechanisms.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/274951

Flood impact on masonry buildings: The effect of flow characteristics and incidence angle
JOURNAL OF FLUIDS AND STRUCTURES
Autore/i: Postacchini, Matteo; Zitti, Gianluca; Giordano, Ersilia; Clementi, Francesco; Darvini, Giovanna; Lenci, Stefano
Classificazione: 1 Contributo su Rivista
Abstract: Climate change and the raising number of extreme events, such as severe floods, has increased the attention on their effects on urban systems. Urban floods generate important hydrodynamic loads on building and this work proposes a first systematic study on the actions generated by floods with different characteristics (depth, velocity and incidence angle) on masonry buildings. The study is carried out with experimental tests reproducing a masonry bay with scale 1:10, while the effect of the flow hitting the building has been obtained by moving the building in the water at rest. The pressure generated by the fluid at the four walls of the building was recorded using pressure transducers. It has been found that the overpressure acting on the building depends on the flow characteristics in different manner for the frontal, lateral and rear walls. Further, the incidence angle plays a major role in the generation of a pressure gradient along the impacted wall, and significantly affects both peak frequency and spectral energy. Use of theoretical models suggests that (i) the drag coefficient of the building decreases with the Froude number, and only slightly depends on the incidence angle, and (ii) the blocking effect largely affects the hydrodynamics around the structure.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/266247

Advanced Seismic Analyses of “Apennine Churches” Stroked by the Central Italy Earthquakes of 2016 by the Non-Smooth Contact Dynamics Method
Mechanics of Masonry Structures Strengthened with Composite Materials III
Autore/i: Ferrante, Angela; Ribilotta, Elisa; Giordano, Ersilia; Clementi, Francesco; Lenci, Stefano
Editore: Trans Tech Publications Ltd
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The dynamic behaviour and the seismic vulnerability of different masonry “Apennine Churches”, dramatically damaged by the last shocks sequence of 2016 that occurred in Central Italy, have been studied in this paper by means of advanced 3D numerical analyses with the Discrete Element Method (DEM). Thus, a discontinuous approach has been used to assess the dynamic properties and the vulnerability of the masonry structure, through large deformations regulated by the Signorini’s law, concerning the impenetrability between the rigid bodies, and by the Coulomb’s law, regarding the dry-friction model. The major purpose of this study is to highlight that relevant data on the real structural behaviour of historical masonry can be provided through advanced numerical analyses. The comparison between the results of the numerical simulation and the survey of the existing crack pattern of the churches permitted to validate the used approach. Finally, from the results and conclusions of these cases study, it is possible to affirm that the used methodology can be applied to a wide variety of historical masonry structure in Europe.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269329

Damage Assessment of San Francesco Church in Amandola Hit by Central Italy 2016-2017 Seismic Event
Mechanics of Masonry Structures Strengthened with Composite Materials III
Autore/i: Giordano, Ersilia; Ferrante, Angela; Ribilotta, Elisa; Clementi, Francesco; Lenci, Stefano
Editore: Trans Tech Publications Ltd
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Italy is a high seismic risk country since 1900 more than 30 earthquakes with magnitude greater than Mw=5.8 have occurred, and the last one is the Central Italy seismic sequence. The first shock occurred in the 24 August (Mw=6.2) followed by another stronger quake in the 30th October (Mw=6.5). It hit the regions of Marche, Umbria, and Abruzzo heavily causing many deaths, injuries and extensive damages on the cultural heritage. This paper analyses the church of San Francesco in Amadola, located in the Marche region that has been considered condemned for the severe damages reported after these earthquakes. The church is globally analyzed by the application of nonlinear static analysis on a Finite Element Model where the nonlinearity of masonry is taking into account with a proper constitutive law. The study wants to prove how global analysis combined by the local analysis can reproduce the behavior of this structure during a quake, showing that it can repeat the real damages produced by earthquakes.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269332

Tracking Modal Parameter Evolution of Different Cultural Heritage Structure Damaged by Central Italy Earthquake of 2016
Mechanics of Masonry Structures Strengthened with Composite Materials III
Autore/i: Ribilotta, Elisa; Giordano, Ersilia; Ferrante, Angela; Clementi, Francesco; Lenci, Stefano
Editore: Trans Tech Publications Ltd
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The preliminary results of an ambient-vibration based investigation conducted on a large sample of historic masonry towers in the Marche region (Central Italy) are presented, with a focus on the belfry of Collegiata of Santa Maria in Visso (Italy). The assessment procedure includes full-scale ambient vibration testing, modal identification from ambient vibration responses, finite element modeling and dynamic-based identification of the uncertain structural parameters of the model. As the most doubtful parameters, the modulus of elasticity of the masonry is adjusted to achieve the experimental results with numerical model by simple operations.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269330

From TLS to FE analysis: points cloud exploitation for structural behaviour definition. The San Ciriaco's bell tower
INTERNATIONAL ARCHIVES OF THE PHOTOGRAMMETRY, REMOTE SENSING AND SPATIAL INFORMATION SCIENCES
Autore/i: Quattrini, R.; Clementi, F.; Lucidi, A.; Giannetti, S.; Santoni, A.
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269915

Evaluation of different approaches for the seismic vulnerability assessment of RC structures
Proceedings of the International Conference of Computational Methods in Sciences and Engineering 2019, ICCMSE 2019
Autore/i: Gazzani, Valentina; Poiani, Marina; Clementi, Francesco; Pace, Giuseppe; Lenci, Stefano
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The seismic vulnerability of school buildings located in the municipality of Trecastelli (Marche, Central Italy) is evaluated with three different numerical models: the lumped plasticity, the distributed plasticity (fibre) and the 3D Continuum FE approaches. Nonlinear static (pushover) analyses are performed to assess the global seismic behaviour of the structures, and the limitations in the representativeness respect to the reality of different approaches are analysed
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/272691

Open challenges towards a seismic protection of new and existing buildings
Proceedings of the International Conference on Numerical Analysis and Applied Mathematics 2018, ICNAAM 2018
Autore/i: Clementi, F.; Milani, G.; Fabbrocino, F.; Formisano, A.
Editore: American Institute of Physics Inc
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269305

Comparative fragility methods for seismic assessment of masonry buildings located in Muccia (Italy)
JOURNAL OF BUILDING ENGINEERING
Autore/i: Chieffo, N.; Clementi, F.; Formisano, A.; Lenci, S.
Classificazione: 1 Contributo su Rivista
Abstract: The current paper focuses on a sector of the historic centre of Muccia, in the district of Macerata (Italy), affected by the seismic sequence that involved Central Italy in 2016. The main goal is comparison, in terms of fragility curves, among two vulnerability assessment methodologies (empirical and mechanical). The study area has been structurally and typologically identified according to the Building Typology Matrix (BTM). Physical vulnerability analysis of the urban-sector was performed through application of an index-based method, specifically for masonry building aggregates. An isolated masonry building, damaged after the seismic sequences, has been selected as a case study. For the assessed building, empirical fragility curves are presented according to Guagenti & Petrini’s correlation law. Furthermore, a numerical model has been set up by using the macro-element approach, which has allowed to perform non-linear static analyses. Mechanical properties of masonry were defined according to the New Technical Codes for Constructions (NTC18), assuming a limited knowledge level (LC1). Refined mechanical fragility functions have been derived and compared to the empirical ones. Analysis results have shown that the empirical method tends to overestimate by 5% and 10% the expected damage for slight and moderate thresholds. For PGA values greater than 0,3 g the damage levels decreased by 30% and 20%, with reference to the near collapse and collapse conditions, respectively.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267525

Cultural Heritage and earthquake: The case study of San Francesco’s church in Amandola (Central Italy)
2019 IMEKO TC4 International Conference on Metrology for Archaeology and Cultural Heritage, MetroArchaeo 2019
Autore/i: Giordano, E.; Ferrante, A.; Clementi, F.; Milani, G.; Formisano, A.
Editore: IMEKO-International Measurement Federation Secretariat
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Italy is a high seismic risk country. Since 1900 more than 30 earthquakes with magnitude greater than Mw=5.8 occurred, and the last one is the Central Italy seismic sequence. It heavily hit the regions of Marche, Umbria, and Abruzzo causing many deaths, injuries and extensive damages on the cultural heritage. This paper analyses the church of San Francesco in Amadola, located in the Marche region that has been considered condemned for the severe damages reported after these earthquakes. The church is globally analyzed by the application of nonlinear static analysis on a Finite Element Model where the nonlinearity of masonry is taking into account with a proper constitutive law. The study wants to prove how global analysis combined by the local analysis can reproduce the behavior of this structure during a quake, showing that it can repeat the real damages produced by earthquakes.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/275184

Tracking modal parameters evolution of a school building during retrofitting works
BULLETIN OF EARTHQUAKE ENGINEERING
Autore/i: Pierdicca, Alessio; Clementi, Francesco; Fortunati, Andrea; Lenci, Stefano
Classificazione: 1 Contributo su Rivista
Abstract: During a seismic improvement intervention that lasted more than one year, a reinforced concrete (RC) school building had been surveyed through dynamic monitoring, granting continuous updates on its global response. Operational Modal Analysis (OMA) was carried out to have a proper understanding of the structure’s dynamic evolution, using a Finite Element Model (FEM) to perform a non-invasive and quantitative structural assessment taking into account the interactions with the surroundings. During the whole restoration works, the long-term (periodic) monitoring campaign showed the increment of the building performance remarked by the variation of natural frequencies. Also, the experimental assessment of the influence of infill masonry panels on the dynamics of RC frame is shown at each upgraded configuration. Additional restoration works, that may eventually occur, could benefit from the data collected during the present Ambient Vibration Survey (AVS), providing useful parameters to enhance the retrofitting and the dynamic behavior of the structure.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/260611

Damage Assessment by Numerical Modeling of Sant'Agostino's Sanctuary in Offida During the Central Italy 2016–2017 Seismic Sequence
FRONTIERS IN BUILT ENVIRONMENT
Autore/i: Giordano, Ersilia; Clementi, Francesco; Nespeca, Andrea; Lenci, Stefano
Classificazione: 1 Contributo su Rivista
Abstract: The subject of this work is the Sant'Agostino Sanctuary in Offida (Italy); we investigated both the dynamic behavior and the seismic vulnerability of the complex, used nowadays in its parts as school building, oratory, and church. Offida is in central Italy; the village has been severely damaged by the last seismic events of 2016. The sanctuary was heavily damaged by the earthquake of 24 August 2016. We recurred to finite elements to estimate the vulnerability of the sanctuary and its dynamic response, considering masonry's non-linear behavior by means of proper constitutive assumptions. To estimate how the monastery bears the lateral loads related to the expected demands resulting from seismic actions (N2 method) using non-linear static analysis (Pushover), we recurred to a homogenized material and smeared cracking and crushing constitutive law. As may be remarked by observing buildings that share the same features of the sanctuary and, moreover, by comparing seismic demand vs. capacity, the structure is prone to massive damage leading to collapse. The paper underlines how advanced numerical analysis grants fundamental data on how historical masonry buildings behave under seismic action, providing a method that may easily be implemented at historic monasteries in Europe.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/262744

The Non-smooth tale of “Apennine Churches” stroked by the Central Italy Earthquakes of 2016
2019 IMEKO TC4 International Conference on Metrology for Archaeology and Cultural Heritage, MetroArchaeo 2019
Autore/i: Ferrante, A.; Giordano, E.; Clementi, F.; Milani, G.; Formisano, A.
Editore: IMEKO-International Measurement Federation Secretariat
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The dynamic behavior and the seismic vulnerability of different masonry “Apennine Churches”, dramatically damaged by the last shocks sequence of 2016 that occurred in Central Italy, have been studied in this paper by means of advanced 3D numerical analyses with the Discrete Element Method (DEM). Thus, a discontinuous approach has been used to assess the dynamic properties and the vulnerability of the masonry structure, through large deformations regulated by the Signorini’s law, concerning the impenetrability between the rigid bodies, and by the Coulomb’s law, regarding the dry-friction model. The major purpose of this study is to highlight that relevant data on the real structural behavior of historical masonry can be provided through advanced numerical analyses. The comparison between the results of the numerical simulation and the survey of the existing crack pattern of the churches permitted to validate the used approach. Finally, from the results and conclusions of these cases study, it is possible to affirm that the used methodology can be applied to a wide variety of historical masonry structures in Europe.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/275183

Design, analysis and retrofitting of civil structures and infrastructures in Seismic Prone Areas
Proceedings International Conference of Computational Methods in Sciences and Engineering 2019, ICCMSE 2019
Autore/i: Clementi, Francesco; Formisano, Antonio; Milani, Gabriele
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/272689

Sustainable Engineering for Resilient Built and Natural Environments
The First Outstanding 50 Years of “Università Politecnica delle Marche”
Autore/i: Alici, Antonello; Bocci, Maurizio; Bonvini, Paolo; Brocchini, Maurizio; Calamai, Alessandro; Canestrari, Francesco; Capozucca, Roberto; Carbonari, Alessandro; Carbonari, Sandro; Cardone, Fabrizio; Clementi, Francesco; Clini, Paolo; Cocchi, Giammichele; Corvaro, Sara; Darvini, Giovanna; Davì, Fabrizio; Dezi, Luigino; Di Giuseppe, Elisa; D’Orazio, Marco; Ferretti, Maddalena; Ferrotti, Gilda; Gara, Fabrizio; Giretti, Alberto; Graziani, Andrea; Lancioni, Giovanni; Lemma, Massimo; Lenci, Stefano; Lorenzoni, Carlo; Malinverni, Eva Savina; Mancinelli, Alessandro; Mariano, Fabio; Mentrasti, Lando; Mondaini, Gianluigi; Montecchiari, Piero; Munafò, Placido; Naticchia, Berardo; Postacchini, Matteo; Quagliarini, Enrico; Quattrini, Ramona; Ragni, Laura; Serpilli, Michele; Soldini, Luciano; Virgili, Amedeo; Zampini, Giovanni
Editore: Springer
Classificazione: 2 Contributo in Volume
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/272866

An Overview of the Structural Safety-Oriented Research in the Region Marche Seismic Area
The First Outstanding 50 Years of “Università Politecnica delle Marche”
Autore/i: Capozucca, R.; Carbonari, S.; Clementi, F.; Cocchi, G.; Davi, F.; Dezi, L.; Gara, F.; Lancioni, G.; Lenci, S.; Mentrasti, L.; Ragni, L.; Serpilli, M.
Editore: Springer, Cham
Classificazione: 2 Contributo in Volume
Abstract: In recent years, Italy has been hit by earthquakes, causing significant damage to masonry and reinforced concrete (RC) structures. Especially, common buildings and ordinary structures in many small historical towns of Italian central regions, such as Marche, have suffered dramatic consequences and destruction. Dynamic analysis and seismic structural safety are important topics in civil engineering, which have been studied and deepened for many years by the researchers of the Structural Division of the Department of Civil and Building Engineering, and Architecture of UnivPM. The researches have been oriented towards the investigation of structures under seismic loads in order to improve the knowledge of the structural response under high actions, due to the soil dynamic movements and, thus, define adequate techniques to strengthen the damaged structures. In this paper we present a wide spectrum of main results of our research group, comprising experimental studies, vulnerability analysis and assessment of existing structures, new methods of modelling and theoretical approaches to define the dynamic behavior of structures, also in presence of damage. Finally, we show and discuss new prospects of research for safety, employing advanced techniques and materials to prevent collapse and/or relevant damages in structures.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/281739

Damage assessment by the non-smooth contact dynamics method of the iconic crumbling of the clock tower in Amatrice after the 2016 Central Italy seismic sequence
Proceedings of the International Conference on Numerical Analysis and Applied Mathematics 2018, ICNAAM 2018
Autore/i: Clementi, F.; Milani, G.; Gazzani, V.; Poiani, M.; Lenci, S.
Editore: American Institute of Physics Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The dynamics of the medieval civic clock tower of Amatrice (Rieti-Italy) has been studied using the Non-Smooth Contact Dynamics (NSCD) method, implementing a discrete element numerical model in the LMGC90© code. Schematised as a system of rigid blocks, undergoing frictional sliding and plastic impacts, the tower has exhibited complex dynamics, because of the geometrical non-linearity and the non-smooth nature of the contact laws. Numerical simulations are performed with the aim of comparing the numerical result and the observed damages after the seismic sequence of the Central Italy earthquakes.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269306

Influence of FE Modelling Approaches on Vulnerabilities of RC School Buildings and Proposal of a CFRP Retrofitting Intervention
THE OPEN CONSTRUCTION & BUILDING TECHNOLOGY JOURNAL
Autore/i: Gazzani, V.; Poiani, M.; Clementi, F.; Pace, G.; Lenci, S.
Classificazione: 1 Contributo su Rivista
Abstract: Background: The vulnerability assessment of existing school buildings against earthquakes represents a priority concern for society. In recent years, several countries promote seismic rehabilitation projects of school buildings, including the allocation of funds to regions with high seismic hazard. Objectives: This research aims to highlight some key role aspects related to difficulties encountered in the numerical modelling of RC structures hosting school activities. This work evaluates the seismic vulnerability of school buildings located in the municipality of Trecastelli (Marche, Central Italy) to quantify the effective influence of typical and specific seismic vulnerabilities detected on the global seismic behaviour of each building. The effectiveness of a possible Carbon Fibre Reinforced Polymer (CFRP) local strengthening intervention, for the case study, aimed to confine unconfined beam-column joints is also considered. Methods: Three different numerical models of a Reinforced Concrete (RC) school building are implemented with the lumped plasticity, the distributed plasticity (fibre) and the 3D Continuum Finite Element (FE) approaches. Nonlinear static (pushover) analyses are performed to assess the global seismic behaviour of the structure, and the limitations to represent the reality with different approaches. After the seismic vulnerability assessment of the case study, a CFRP retrofitting intervention is proposed to confine external beam-column joints. Results: The comparison of the numerical results of three models shows that the fibre model is the least suitable means to represent shear problems, while the lumped plasticity model is closer to reality than the previous one even if it does not take into account the concomitance of bending, shear and axial force and the interaction between them in the inelastic response. Of course, the 3D Continuum model is the most accurate representation to describe the complex and combined mechanisms developed in the joint panels. Nonlinear static (pushover) analyses carried out on unreinforced and reinforced structures of Continuum model demonstrate that the Fibre Reinforced Polymer (FRP) strengthening improves the displacement capacity of the structure. Conclusion: This study has highlighted the strengths and weaknesses of different modelling types. The meaningful information about mechanisms developed in joints given by the 3D Continuum FE model is useful to identify shortcomings of the design project and to conceive a retrofitting strengthening intervention. CFRP sheets externally bonded on beam-column joints may improve the seismic frame performances without a significant change of the structural stiffness, promoting a ductile failure mode with a higher displacement capacity than the unreinforced case.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/272403

Damage survey and advanced seismic analyses of different masonry churches after the central Italy earthquake of 2016
COMPDYN 2019 Proceedings
Autore/i: Clementi, F.; Giordano, E.; Ferrante, A.; Lenci, S.
Editore: National Technical University of Athens
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This study presents a detailed failure analysis of different masonry churches, which were severely damaged during the 2016 Centre of Italy seismic sequence, using nonlinear (i.e., kinematic limit and pushover) analyses. The main aims of the numerical investigations are: (i) to carry out a sufficiently wide sensitivity study on different specific case studies to have an insight into the role played by the geometry - which is always unique for churches - and by the irregularities; (ii) to validate or address the limits of applicability of the most widespread conventional static approaches recommended by Italian Code.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/274950

Dynamic Behavior of an Inclined Existing Masonry Tower in Italy
FRONTIERS IN BUILT ENVIRONMENT
Autore/i: Ferrante, Angela; Clementi, Francesco; Milani, Gabriele
Classificazione: 1 Contributo su Rivista
Abstract: The renaissance bell tower of San Benedetto in Ferrara (Italy) has been investigated to understand its nonlinear dynamics correctly with the Non-Smooth Contact Dynamic (NSCD) method. The masonry structure has been modeled with the Discrete Element Methods (DEM), assuming rigid blocks and frictional joints, with the aim to recreate the tower in the actual configuration with the inclination and in a fictitious perfect vertical shape in order to assess the influence of the initial slope on its dynamics. The contacts between blocks are governed by the Signorini's impenetrability condition and by dry-friction Coulomb's law. Both configurations have been analyzed inducing real seismic excitations of various types and intensities, corresponding to the six main seismic events of the last few decades in Italy. Thus, the seismic vulnerability of the examined tower is clearly expressed in the numerical results, proving the effects due to the inclination on the amplification of the vulnerability and the several possible collapse mechanisms. Moreover, the NSCD has demonstrated to be a powerful numerical technique to obtain highly accurate results in the structural analyses of masonry structures in the nonlinear range.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/264471

Mechanical characterization of unfired earth via numerical assessment of the experimental data
Proceedings of the International Conference on Numerical Analysis and Applied Mathematics 2018, ICNAAM 2018
Autore/i: Clementi, Francesco; Cocchi, Giammichele; Lenci, Stefano
Editore: American Institute of Physics Inc
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The current work presents the first results on the determination of reliable numerical models of earthen blocks under different loading conditions. Uniaxial compression and 3-points bending tests were performed. Experimental behavior was modelled with a nonlinear model able to describe the cracking behavior. The simplified approach based on macro-modelling shows a satisfactory accuracy and low computational costs. The numerical results are in good agreement with the post-elastic behavior observed in the experimental campaign
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269304

On the nonlinear behaviour of unfired dry earth
Proceedings of the International Conference of Computational Methods in Sciences and Engineering 2019, ICCMSE 2019
Autore/i: Giordano, Ersilia; Clementi, Francesco; Cocchi, Giammichele; Marcheggiani, Laura
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The current work presents the first results on the determination of reliable numerical models of earthen blocks under different loading conditions. Uniaxial compression and 3-points bending tests were performed. Experimental behavior was modelled with a nonlinear model able to describe the cracking behavior. The simplified approach based on macro-modelling shows a satisfactory accuracy and low computational costs. The numerical results are in good agreement with the post-elastic behavior observed in the experimental campaign.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/272690

FLOOD IMPACTS ON BUILDINGS: FIRST EXPERIMENTAL AND NUMERICAL RESULTS
Proceedings del XXXVI Convegno Nazionale di Idraulica e Costruzioni Idrauliche
Autore/i: Brocchini, Maurizio; Capozucca, Roberto; Clementi, Francesco; Darvini, Giovanna; Giordano, Ersilia; Lenci, Stefano; Postacchini, Matteo; Zitti, Gianluca
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/263397

Monitoring cultural heritage buildings: The San Ciriaco bell-tower in Ancona
Proceedings of the International Conference of Computational Methods in Sciences and Engineering 2018 (ICCMSE-2018)
Autore/i: Ribilotta, Elisa; Clementi, Francesco; Pellegrino, Marco; Poiani, Marina; Gazzani, Valentina; Santilli, Graziano; Lenci, Stefano
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The preliminary results of an ambient-vibration based investigation conducted on the San Ciriaco Belfry in Ancona (Italy) is presented. The assessment procedure includes full-scale ambient vibration testing, modal identification from ambient vibration responses, finite element modeling and dynamic-based identification of the uncertain structural parameters of the model. As the most doubtful parameters, the modulus of elasticity of the masonry is adjusted to achieve the experimental results with numerical model by simple operations
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/262450

Iconic crumbling of the clock tower in Amatrice after 2016 central Italy seismic sequence: advanced numerical insight
Proceedings of XIV International Conference on Building Pathology and Constructions Repair – CINPAR 2018
Autore/i: Poiani, M.; Gazzani, V.; Clementi, F.; Milani, G.; Valente, M.; Lenci, S.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The present paper investigates from an advanced numerical point of view the progressive damage of the Amatrice (Rieti, Italy) civic clock tower, after a long sequence of strong earthquakes that struck central Italy in 2016. Two advanced numerical models are here utilised to have an insight into the modalities of progressive damage and the behaviour of the structure under strong non-linear dynamic excitations, namely a Non-Smooth Contact Dynamics (NSCD) and a FE Concrete Damage Plasticity (CDP) models. In both cases, a full 3D detailed discretization is adopted. From the numerical results, both the role played by the actual geometries and the insufficient resistance of the constituent materials are envisaged, showing a good match with actual crack patterns observed after the seismic sequence.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/262325

Axial-transversal coupling in the nonlinear dynamics of a beam with an inclined roller
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
Autore/i: Lenci, S.; Clementi, F.
Classificazione: 1 Contributo su Rivista
Abstract: The nonlinear oscillations of an Euler–Bernoulli beam hinged at one end and having a roller support sliding on a inclined line on the other end are investigated for the first time (to the best of the authors’ knowledge). Free and forced dynamics are studied, and the backbone curve and frequency response curve are obtained by the multiple time scale method. These results allow us to detect analytically the main features of the nonlinear dynamics, in particular the hardening/softening dichotomy, and how it is influenced by the various beam parameters. Furthermore, the analytical results are compared with finite element simulations to check their reliability. The main goal of the paper is that of investigating the coupling between axial and transversal displacements, which appears yet in the linear regime (first order solution) due to the slope of the constraint. An element of novelty consists of showing the qualitative and quantitative changes that the coupling undergoes passing from small (linear regime) to moderate and large (nonlinear regime) displacements.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/258881

Seismic Assessment of a Monumental Building through Nonlinear Analyses of a 3D Solid Model
JOURNAL OF EARTHQUAKE ENGINEERING
Autore/i: Clementi, F.; Gazzani, V.; Poiani, M.; Mezzapelle, P. A.; Lenci, S.
Classificazione: 1 Contributo su Rivista
Abstract: The paper analyzes the static behavior and the seismic vulnerability of the “San Francesco ad Alto” building in Ancona (Italy), which is currently used as a Regional Headquarter of the Marche Region by the Italian Army and was formerly a monastery. The global static structural behavior and the dynamic properties have been evaluated using the Finite Element modeling technique, in which the nonlinear behavior of masonry has been taken into account by proper constitutive laws. The concepts of homogenized material and smeared cracking are used to evaluate the capacity of the monastery to withstand lateral loads together with the expected demands resulting from seismic actions (N2 method), using a nonlinear static analysis (pushover). The comparison of seismic demand and capacity confirms the susceptibility of these types of buildings to extensive damage and collapse, as frequently observed in similar buildings. This paper aims to point out that advanced numerical analyses can offer significant information on the understanding of the actual structural behavior of historical buildings. It is believed that the methodology and the overall conclusions of this case study are valid for many historical monasteries in Europe.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/247516

Existing and new structures in seismic prone areas: Advanced numerical modelling and experimentation
Proceedings of the INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2018 (ICCMSE 2018)
Autore/i: Milani, Gabriele; Formisano, Antonio; Clementi, Francesco
Editore: AIP Conference Proceedings
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/262424

Numerical model upgrading of ancient bell towers monitored with a wired sensors network
Proceedings of the International Masonry Society Conferences
Autore/i: Clementi, F.; Pierdicca, A.; Milani, G.; Gazzani, V.; Poiani, M.; Lenci, S.
Editore: International Masonry Society
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In this work, the opportunities provided by dynamic identification techniques for non-destructive evaluation of heritage structures are discussed with a focus on different bell towers, located in the Ferrara Province (Italy). All of them were stricken by a long seismic sequence (Emilia Romagna, North-East of Italy, May-June 2012 seismic sequence) and they are investigated in detail to have an insight into their dynamic behaviour. Furthermore, the experimental investigations and the operational modal analysis results are presented and they are useful for defining the Finite Element (FE) models of the towers within a continuum approach. The monitoring system consists of several sensors properly connected. The positioning of the instrumentation has been conditioned by many operative problems due to the limited accessibility of the structures, both related to the main access and to reaching the top. However, it has been possible to identify with a certain confidence the first three frequencies of the towers and their corresponding mode shapes. The results carried out after the FE updating procedure may be considered very good. The material data values estimated in this way will constitute an important reference for the evaluation of the state of the building.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/264150

The non-smooth contact dynamics method for the analysis of an ancient masonry tower
Proceedings of INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2018 (ICCMSE 2018)
Autore/i: Clementi, Francesco; Milani, Gabriele; Gazzani, Valentina; Poiani, Marina; Cocchi, Giammichele; Lenci, Stefano
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The dynamics of a medieval tower, inside the Basilica of San Benedetto in Ferrara (Italy), subjected to transversal dynamic loadings has been analyzed by using a distinct element code which implements the Non-Smooth Contact dynamics method. Since the contact between blocks is governed by the Signorini’s impenetrability condition and the dry-friction Coulomb’s law, the tower exhibits discontinuous dynamics. The sliding motions of blocks are non-smooth functions of time. Numerical simulations are performed with the aim of investigating the influence of the friction coefficient but also of the amplitude and frequency of the excitation at the base.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/262449

Modal parameters identification with environmental tests and advanced numerical analyses for masonry bell towers: a meaningful case study
Proceedings of XIV International Conference on Building Pathology and Constructions Repair – CINPAR 2018
Autore/i: Gazzani, V.; Poiani, M.; Clementi, F.; Milani, G.; Lenci, S.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In the first part, a dynamic monitoring for non-destructive evaluation of heritage structures is discussed with reference to a case study, namely the Pomposa Abbey belfry, located in the Ferrara Province (Italy). The main dynamic parameters constitute an important reference to define an advanced numerical model, discussed in the second part, based on Non-Smooth Contact Dynamics (NSCD) method. Schematised as a system of rigid blocks undergoing frictional sliding and plastic impacts, the tower has exhibited complex dynamics, because of both geometrical nonlinearity and the non-smooth nature of the contact laws. First, harmonic oscillations have been applied to the basement of the tower and a systematic parametric study has been conducted, aimed at correlating the system vulnerability to the values of amplitude and frequency of the assigned excitation corroborated by the dynamic identification results. In addition, numerical analyses have been done to highlight the effects of the friction coefficient and of the blocks geometries on the dynamics, in particular on the collapse modes. Finally, a study of the tower stability against seismic excitations has been addressed and 3D simulations have been performed with a real earthquake.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/262326