36 pubblicazioni classificate nel seguente modo:

Shell-Based Finite Element Modeling of Herøysund Bridge in Norway
MODELLING
Autore/i: Singh, Harpal; Azad, Zeeshan; Nicoletti, Vanni
Classificazione: 1 Contributo su Rivista
Abstract: This paper thoroughly examines the application of the Finite Element Method (FEM) to the numerical modal analysis of Herøysund Bridge, focusing on the theoretical backdrop, the construction process, and FEM techniques. This work examines the specific applied FEM approaches and their advantages and disadvantages. This Herøysund Bridge analysis employs a two-pronged strategy consisting of a 3D–solid model and a shell model. To forecast the physical behavior of a structure, assumptions, modeling methodologies, and the incorporation of specific components such as pillars are applied to both approaches. This research also emphasizes the importance of boundary conditions, examining the structural effects of standard Earth gravity, a post-tensioned load, and a railing and asphalt load. The Results section thoroughly explores the mode shapes and frequencies of the 3D–solid and shell models. The conclusion of this work includes findings obtained from the study, implications for Herøysund Bridge, and a comparison of both modeling strategies. It also incorporates ideas for future research and guides employing FEM 3D–solid and shell methods to design and construct more efficient, resilient, and durable bridge structures.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/325513

Comparison of Condition Rating Systems for Bridges in Three European Countries
APPLIED SCIENCES
Autore/i: Matos, Jc; Nicoletti, V; Kralovanec, J; Sousa, Hs; Gara, F; Moravcik, M; Morais, Mj
Classificazione: 1 Contributo su Rivista
Abstract: Europe faces many problems connected to ageing infrastructure which was built in the second half of the 20th century. Bridges are one of the crucial elements of these infrastructures. In recent years, European countries have witnessed many failures of bridges across the continent. For example, the collapse of Viadotto Polcevera in Genoa caught the attention of society regarding its tragic consequences. Therefore, engineers must deal with the assessment of existing bridges which is essential for proper decision-making. Condition rating systems for bridges vary from country to country. Consequently, these differences in the methodology can lead to different conclusions related to the future service of assessed structures. For these reasons, this paper briefly describes condition rating systems for road bridges in Italy, Slovakia, and Portugal and defines the differences in the methodology. Subsequently, the obtained conclusions are compared and discussed. The aim of the paper is to encourage standardization in the assessment of bridge health conditions within European countries, highlighting the differences in the current systems adopted by various countries.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/325511

First Applications and Results of the SHM of Residential Buildings in Italy
Lecture Notes in Civil Engineering
Autore/i: Nicoletti, V.; Quarchioni, S.; Carbonari, S.; Gara, F.
Editore: Springer Science and Business Media Deutschland GmbH
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The structural health assessment of buildings during their life is a very actual and important topic to monitor effects of ageing and, more importantly, to exclude risks for users after exceptional events. This evaluation, periodically carried out, provides important information about the structural health condition and may be crucial to evaluate the need of interventions after exceptional events, or simply to schedule the building maintenance. In this framework, a monitoring system should be installed not only on strategic constructions and infrastructures, but also on residential buildings. The paper discusses about the dynamic structural health monitoring of a considerably number of residential buildings located in Central Italy (Marche Region). The framework adopted to design the structural health monitoring systems and to post-process the acquired data, as well as the adopted instruments, are described, starting from the preliminary dynamic identification of the building to the monitoring system design and installation. The architecture for data acquisition, transfer and storage are also discussed. Moreover, some results of the monitoring are presented, and their relevance in the context of structural assessment after exceptional events (e.g., earthquakes) is addressed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/322771

Vibration-Based Test Results for the Investigation of the Infill Masonry Wall Damage
Lecture Notes in Civil Engineering
Autore/i: Nicoletti, V.; Arezzo, D.; Carbonari, S.; Gara, F.
Editore: Springer Science and Business Media Deutschland GmbH
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Infills are one of the most common non-structural elements worldwide adopted to build external and internal partition walls in framed structures. Many types of infills can be encountered in practical applications, characterized by different construction typologies and materials, but the most adopted ones are those realized with masonry. It is well known that infill masonry walls suffered lot of damage in the past as a consequence of earthquake excitations and, moreover, they were cause of undesirable effects on the structural seismic performance, such as the activation of soft story mechanisms and shear failure of short columns. For these reasons, the infill contribution on the seismic behaviour of buildings should be investigated both during the design process of new structures and the assessment of the existing ones. The aim of this paper is to investigate the usefulness of vibration data for the damage detection in infilled frame structures starting from the tracking of both the stiffness and modal properties. To this aim, an experimental campaign was performed on a laboratory steel-concrete composite frame with infill masonry walls. The tested mock-up was subjected to stepped-increasing cyclic displacements that produced a progressive in-plane damage of infills, up to their complete damage. In the meantime, vibration-based tests characterized by different level of input excitation provided to the structure, were performed to capture the effects of the infill damage on the mock-up global dynamic response. Results provide useful information for the detection and tracking of damage to non-structural elements during and after low and moderate seismic events, contributing to a better interpretation of data provided by structural health monitoring systems. Finally, a monitoring strategy suitable for new infilled buildings is proposed, with the main aim of providing a contribution in the context of differentiating between structural and non-structural damage, especially in case of blind monitoring.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/312287

The Monitoring System of the New Filomena Delli Castelli Cable-Stayed Bridge
Lecture Notes in Civil Engineering
Autore/i: Nicoletti, V.; Amico, L.; Martini, R.; Carbonari, S.; Gara, F.; Dezi, F.
Editore: Springer Science and Business Media Deutschland GmbH
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Bridges play a primary role in the road and railway networks, and their inoperability due to damage or collapses following natural disasters or due to ageing, have impacts from both the social and the economic perspectives. For these reasons, an accurate control of their health conditions is of paramount importance, especially for bridges located on strategic roadways. This paper deals with the design and the installation of the structural health monitoring system of the newly built “Filomena Delli Castelli” cable-stayed bridge over the Saline river, in Central Italy. The bridge has a steel-concrete composite deck about 190 m long, with a peculiar plan shape given by the presence of a pedestrian and cycling path with curvilinear layout in the downstream side of the deck. The monitoring system is described, discussing about the adopted instrumentations and their location for both static and dynamic measurements. Moreover, the preliminary tests and studies that supported the design of the monitoring system, are also presented. Then, issues relevant to data acquisition, transfer and storage are addressed. Preliminary data from the monitoring system are also shown, and considerations about their usefulness in a structural health monitoring process are provided.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/322772

Experimental Tests and Numerical Analyses for the Dynamic Characterization of a Steel and Wooden Cable-Stayed Footbridge
INFRASTRUCTURES
Autore/i: Nicoletti, Vanni; Quarchioni, Simone; Tentella, Luca; Martini, Riccardo; Gara, Fabrizio
Classificazione: 1 Contributo su Rivista
Abstract: Vibrations are an issue of increasing importance in current footbridge design practice. More sophisticated footbridges with increasing spans and more effective construction materials result in lightweight structures and a high ratio of live load to dead load. As a result of this trend, many footbridges have become more susceptible to vibrations when subjected to dynamic loads. The most common dynamic loads on footbridges, other than wind loading, are pedestrian-induced footfall forces due to the movement of people. This paper concerns the experimental and numerical dynamic characterization of a newly built steel and wooden cable-stayed footbridge. The footbridge was dynamically tested in situ under ambient vibration, and the results allowed the real dynamic behavior of the footbridge to be captured. The dynamic response under pedestrian dynamic loads was also investigated and compared with the limitations provided by the main international codes and guidelines for footbridge serviceability assessment. A numerical model of the footbridge was also developed and updated based on the experimental outcomes. Then, the calibrated model was used to numerically assess the footbridge's serviceability following the guideline prescriptions for pedestrian load simulation, and the design accuracy was also validated. This paper aims to increase the state-of-the-art knowledge about footbridge dynamic testing so as to support the design of new and futuristic structures as well as prove the effectiveness of using the requirements of codes and guidelines for footbridge serviceability assessment by adopting a calibrated numerical model.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/320351

Model Updating of Cultural Heritage Buildings Through Swarm Intelligence Algorithms
INTERNATIONAL JOURNAL OF ARCHITECTURAL HERITAGE
Autore/i: Gara, F; Nicoletti, V; Arezzo, D; Cipriani, L; Leoni, G
Classificazione: 1 Contributo su Rivista
Abstract: Masonry buildings constitute a great Italian historical and cultural heritage, but they were also severely damaged by earthquakes over the centuries. Therefore, to assess their structural and seismic performance, it is crucial to gain a refined and trustworthy numerical model adopting model updating techniques, sometimes based on artificial intelligence algorithms. This article deals with the development and the updating of a finite element model of an historical church that account for the presence of both the seismic damage and securing systems. The model updating is performed adopting the particle swarm optimization algorithm and is based on the comparison between numerical and experimental modal parameters, the latter achieved by an extensive dynamic test campaign. The obtained calibrated numerical model has been adopted to support the restoration work design, as well as the design of a structural health monitoring system that has been permanently installed on the church.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/325512

Modelling Strategies for the Updating of Infilled RC Building FEMs Considering the Construction Phases
BUILDINGS
Autore/i: Nicoletti, V.; Gara, F.
Classificazione: 1 Contributo su Rivista
Abstract: This paper deals with modelling strategies for the updating of Finite Element Models (FEMs) of infilled Reinforced Concrete (RC) frame buildings. As is known, this building typology is the most adopted worldwide for residential houses and strategic buildings, such as hospitals, schools, police stations, etc. The importance of achieving trustworthy numerical models for these kinds of structures, especially the latter ones, is clear. The updating procedure mainly consists in changing the geometrical and mechanical material properties of models until pre-determined convergence criteria are verified, the latter based on the comparison between numerical and experimental outcomes. In this work, the modelling strategies that can be adopted to refine FEMs of infilled RC buildings are treated in-depth, starting from the simple model usually developed for design purposes. Modelling techniques relevant to the geometry, the mechanical properties, the mass, and the restraint conditions of the model are discussed. Moreover, the approaches that can be adopted to calibrate numerical models during the construction process are addressed as well. Then, an application of the proposed strategies is provided with reference to a real building that was investigated during its construction. The proposed modelling strategies proved to be effective in the model updating of the considered building and provide useful support for the calibration of FEMs of this building typology in general.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/313850

Operational Modal Analysis as a Support for the Development of Digital Twin Models of Bridges
INFRASTRUCTURES
Autore/i: Nicoletti, V.; Martini, R.; Carbonari, S.; Gara, F.
Classificazione: 1 Contributo su Rivista
Abstract: Many transportation infrastructures all around the world are facing new challenges in terms of ageing and loss of performance. The infrastructural asset managers are required to perform scrupulous control of the health condition of the infrastructures over time and to execute the required maintenance works. In this context, digital twin models of the infrastructures should have a key role to simplify and speed up the procedures for proper maintenance. This paper discusses the advantages of developing digital twin models for the management of infrastructures, with a focus on bridges. In particular, the role of dynamic tests performed on bridges for the development of digital twin models is addressed, paying attention to test procedures and requirements. Issues such as the quality of instrumentation, the numerosity, and layout of sensors, and the acquisition and post-processing procedures are addressed through applications to two real bridge case studies. Both infrastructures are multi-span pre-stressed RC bridges that were dynamically tested after the restoration and seismic upgrading works. Results of ambient vibration tests and operational modal analyses are described, providing an idea of dynamic test requirements, as well as their use within the framework of the digital twin model creation.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/312270

The usefulness of OMA for evaluating the health status of structures
9th IOMAC International Operational Modal Analysis Conference, Proceedings
Autore/i: Nicoletti, V.; Arezzo, D.; Carbonari, S.; Gara, F.
Editore: International Operational Modal Analysis Conference (IOMAC)
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The health monitoring and the safety assessment of buildings and infrastructures during their life cycle are of paramount importance for assuring the building use with acceptable risks for users, especially after the occurrence of earthquakes or other exceptional events, such as hurricanes, blasts or vehicle impacts. For strategic structures with public functions (e.g., bridges, hospitals, police and fire stations, schools, etc.) the structural health monitoring can provide useful information about the building status, in terms of damage on structural and non-structural elements; if the monitoring system reports alert situations through suitably installed specific sensors, visual inspections and destructive or nondestructive experimental tests can be also executed with the aim of supporting the decision-making process about the building use. The paper discusses about the effectiveness and usefulness of OMA in the assessment of the health conditions of buildings, and in its suitability within a structural health monitoring framework. An experimental campaign was performed on a laboratory steel-concrete composite frame with infill masonry walls: a progressive damage was produced to the non-structural components through cyclic load tests with increasing amplitude displacements, and vibration-based tests were performed with the aim of tracing the evolution of the frame dynamics and modal properties. Results demonstrate that OMAs are suitable for detecting the damage occurring to the non-structural components, while they are less useful in capturing the dissipative capabilities of the resisting nonlinear mechanisms that develop due to damage.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/319352

Nomograms for the pre-dimensioning of RC beam-column joints according to Eurocode 8
STRUCTURES
Autore/i: Nicoletti, V.; Carbonari, S.; Gara, F.
Classificazione: 1 Contributo su Rivista
Abstract: Beam-column joints in reinforced concrete frame buildings are very important elements whose design must be done with particular attention to guarantee the development of full strength and ductility of structural elements, as well as the respect of the hierarchy principles. Nowadays many codes worldwide require the evaluation of the beam-column joint capacity and provide expressions for the verification of this fundamental element. The respect of these verifications may lead the designer to take decisions which can affect, even significantly, the structural component geometry and also the architectural design of buildings. In this paper a simple and fast-to-use graphical tool is provided to support the design of beam-column joints satisfying Eurocode 8 verification expressions. In detail, nomograms are proposed with the great advantage of being largely applicable for all types of beam-column joints. The use of nomograms makes it possible to obtain an estimation of the beam-column joint sizing and of the horizontal hoop amount. If the joint dimension reveals to be underestimated and/or the hoop amount leads to an excessive close spacing, the designer can promptly modify the design at the early stages of the design process. Worked examples are also proposed, and many types of nomograms are reported in a dedicated appendix.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/298243

SHM of historical buildings: The case study of Santa Maria in Via church in Camerino (Italy)
Procedia Structural Integrity
Autore/i: Arezzo, D.; Quarchioni, S.; Nicoletti, V.; Carbonari, S.; Gara, F.; Leonardo, C.; Leoni, G.
Editore: Elsevier B.V.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Historical buildings constitute a huge heritage for the Italian country, and they deserve to be preserved to be handed over in good condition for future generations. As well know, Italy is a prone earthquake country and many earthquakes occurred over time producing awful consequences in terms of human losses and building damage. Historical buildings are typically the most damaged ones since they were built often with poor materials and conceived to sustain only gravitational loads. The preservation of these buildings is not a trivial task as structural retrofits have to be carried out not only in a proper way, but also timely in case the actual conditions of the construction may worse over time. Since large-scale rapid interventions after an earthquake are almost impossible, instrumenting damaged structures with appropriate sensors and analyzing measured data become crucial to control the damage evolution. At the same time, the monitoring of secured structures is essential to evaluate the effectiveness of the interventions and the possible evolution of damage. This paper presents the Structural Health Monitoring (SHM) system installed in the Santa Maria in Via church in Camerino (Central Italy). The church, severely damaged after the seismic sequence that stroke Central Italy in 2016, was secured with a steel structural system aimed at preventing possible collapse of some peculiar components, as the overturning of the massive façade body and the collapse of the slender elliptical drum. The SHM system permanently installed is presented; the latter consists of several sensors of different typologies placed in specific positions to monitor the effectiveness of the securing steel structure and the behavior of the church. Also, the Optimal Sensor Placement (OSP) methodology is adopted to determine the best sensor layout (number and position) to develop the SHM of the case study. Finally, the numerical model developed to support the interpretation of the SHM data, is described.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/318011

Beam-column joint nomogram: A simple and fast-to-use tool to evaluate the joint integrity in RC structures
Procedia Structural Integrity
Autore/i: Nicoletti, V.; Carbonari, S.; Gara, F.
Editore: Elsevier B.V.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Beam-Column Joints (B-CJs) are crucial elements in Reinforced Concrete (RC) frame structures since their behaviour strongly affects the seismic performance of the structures. Indeed, design hierarchy principles of these kind of structures are conceived to obtain the BCJs preservation from premature failure, allowing the structural members to develop their full strength and ductility and assuring a global dissipative structural behaviour. As well known, B-CJs are the last link of the hierarchy chain and are designed in the last step; if code joint verifications are not satisfied, the B-CJ needs to be re-designed, with possible consequences on the redesign of the structural members framing into the joint and, often, on the architectural details. For these reasons, an early knowledge of the BCJs adequacy, since the early stages of the design process, can help engineers and architects to save time and to optimize the architectural and structural design of buildings. In this paper, a new graphical tool for supporting the design of B-CJs in RC frame structures is proposed. Diagrams (called nomograms) are presented, consisting in charts that lead to achieve the BCJ geometric dimensions and hoop amount so that the NTC18 B-CJ verifications are satisfied. The proposed nomograms can be used for all types of joints, and with any kind of geometry since they are dimensionless. Nomograms can simplify the RC building design since they offer an indication of the joint verification outcomes even from the early stages of the design process, i.e., at the moment in which the structure is conceived and built within a finite element model.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/317991

A Good Practice for the Proof Testing of Cable-Stayed Bridges
APPLIED SCIENCES
Autore/i: Innocenzi, R. D.; Nicoletti, V.; Arezzo, D.; Carbonari, S.; Gara, F.; Dezi, L.
Classificazione: 1 Contributo su Rivista
Abstract: This paper presents the results and interpretations of static and dynamic tests that were executed on a newly built cable-stayed steel-concrete composite bridge during the final proof testing. A brief description of the structure, the testing methodology, and the used instrumentation are presented. Then, the test results are widely discussed and interpreted in order to evaluate the bridge performance during the proof test and also to understand the usefulness of each performed test in a proof test framework. All the collected experimental data are also compared to the numerical ones that were obtained through a refined finite element model, in order to check the behavior of the structure. The outcomes of the present work can offer references for the proof testing and monitoring of cable-stayed bridges.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/298401

Optimal sensor placement for the dynamic monitoring of a historical masonry church in central Italy
9th IOMAC International Operational Modal Analysis Conference, Proceedings
Autore/i: Arezzo, D.; Nicoletti, V.; Carbonari, S.; Gara, F.
Editore: International Operational Modal Analysis Conference (IOMAC)
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Italy is a seismic prone country with a great heritage of churches and historic masonry buildings that often suffer damage due to earthquakes. For buildings of high cultural value, the damaged structural systems are usually secured through immediate interventions, with the need of monitoring the evolution of damage in time up to the final restoration. This paper presents some of the results of the research activities carried out on the church of Santa Maria in Via in Camerino, (central Italy), severely damaged by the 2016 Central Italy seismic sequence and secured through various interventions. In particular, a massive external retaining steel structure was built to prevent the collapse of the façade and, in the subsequent years, a static and dynamic monitoring system has been installed with the aim of monitoring the health status of the church and preventing the evolution of the kinematics triggered by the 2016 earthquake. Ambient vibration tests have been performed on the church and its global dynamics has been identified by means of Operational Modal Analysis techniques. Also, a finite element model of the church has been developed, whose parameters have been optimised through the Particle Swarm Optimisation algorithm. Finally, starting from the results of the updated model, the sensor placement was optimised by employing the Effective Independence algorithm, in order to increase the efficiency of the monitoring system in tracking all the preliminarily identified modes.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/319353

Detection of infill wall damage due to earthquakes from vibration data
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS
Autore/i: Nicoletti, V.; Arezzo, D.; Carbonari, S.; Gara, F.
Classificazione: 1 Contributo su Rivista
Abstract: Vibration-based methodologies are nowadays gaining increasing application for the structural health monitoring and damage detection on buildings, especially damage due to earthquakes. A fast and efficient damage recognition on structural and non-structural components can support the decision-making process after exceptional events and may contribute to reduce troubles due to the inoccupancy of buildings. The paper offers insights on the usefulness of vibration data for the damage detection in infilled frame structures starting from the tracking of the stiffness and modal properties of an infilled laboratory steel-concrete composite mock-up subjected to vibration-based tests. The mock-up has been object of an extensive experimental campaign that involved both quasi-static cyclic and dynamic tests characterized by different level of excitation provided to the structure. Cyclic load tests are performed to simulate the effects of earthquakes by progressively increasing the imposed displacement to the cracking and then to the failure of infills. The dynamic tests are executed at the various steps to capture the effects of the infill damage on the global dynamic response triggered by excitations of different amplitudes. Results of dynamic and quasi-static tests are used to correlate the infill damage with the mechanical properties and the modal parameters of the mock-up, as well as with the vibration amplitude, providing information about the damage expected during low and moderate seismic events as a function of the registered dynamic response of the building by structural health monitoring systems.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/310053

Vibration-Based Tests and Results for the Evaluation of Infill Masonry Walls Influence on the Dynamic Behaviour of Buildings: A Review
ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING
Autore/i: Nicoletti, V.; Arezzo, D.; Carbonari, S.; Gara, F.
Classificazione: 1 Contributo su Rivista
Abstract: Tests on infill masonry walls have been widely performed by many researchers and for a long time with the main purpose of characterising the infill performance under earthquake-type excitations. However, most of these works deal with laboratory tests on purpose-built specimens. More recently, vibration-based tests have been also adopted to investigate the influence of the non-structural elements on the dynamic behaviour of buildings, with the advantage that this kind of tests can be performed both on laboratory specimens and on in-situ buildings. However, differently from classical infill tests (i.e., monotonic or cyclic lateral load tests, out of plane tests, etc.), a limited number of works is available in the literature discussing the outcomes and possible procedures for testing infilled structures with vibration-based methods aimed to investigate the role of the non-structural components. This paper presents a literature review of research works dealing with vibration-based tests performed on RC frame structures with the main target of discussing the influence of non-structural components on the dynamics of buildings. Tests on infilled buildings performed during the construction, in operating conditions and after the damage occurred due to earthquake shakings, are discussed. Furthermore, a comprehensive review about papers discussing vibration-based tests performed on infill masonry walls is presented and in-depth investigated with the aim of finding possible correlations between the dynamic test outcomes and the infill geometric and mechanical properties. From this study it comes out the need of further experimental data on both undamaged and damaged infills in order to get more reliable correlations.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295022

Identification of changes in the dynamics of a reinforced concrete building through a machine learning approach for data normalization
9th IOMAC International Operational Modal Analysis Conference, Proceedings
Autore/i: Arezzo, D.; Quarchioni, S.; Nicoletti, V.; Carbonari, S.; Gara, F.
Editore: International Operational Modal Analysis Conference (IOMAC)
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In recent years there has been a growing number of Structural Health Monitoring (SHM) applications based on environmental vibration measurements and Operational Modal Analysis techniques. It is nowadays widely recognised in the scientific literature the need of normalizing data (e.g. modal properties) of vibration-based monitoring systems from variations related to the effects of environmental conditions (e.g. temperature, wind speed, intensity of human activities). In this paper, the results of the dynamic monitoring of a 10-storey reinforced concrete building in central Italy are presented. The building, which is monitored since 2017, hosts the Faculty of Engineering of the Università Politecnica delle Marche and can be considered of strategic importance. During 2021, retrofit works on the structural joints separating the building from adjacent bodies were carried out. This led to a slight modification of its dynamic behaviour; in detail, variations of the modal properties due to the interventions on joints hide beyond those due to environmental conditions and cannot be clearly detected with traditional multivariate statistics techniques for data cleansing. On the contrary, a data cleansing procedure based on the application of an artificial neural network revealed effective to detect the variation of the building dynamic behaviour.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/319355

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

Evolution of Modal Parameters of a Reinforced Concrete Building Subjected to Moderate Earthquakes
Lecture Notes in Civil Engineering
Autore/i: Arezzo, D.; Nicoletti, V.; Carbonari, S.; Gara, F.
Editore: Springer Science and Business Media Deutschland GmbH
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Results of the dynamic monitoring carried out on a school building located in central Italy during the seismic sequence following the main shock of 2016 Central Italy earthquake are presented in this work. The building, located in the historical centre of Camerino (Marche Region), consists of a reinforced concrete frame structure with masonry infill walls. The school was built in the 1960s and was seismically retrofitted in 2013 through the construction of two dissipative towers, according to a recent patented system for the seismic protection of constructions. The system consists on steel truss towers built outside the building, pinned at their base and connected to the building through braces at the floor levels. Towers are equipped with dissipative devices that activate for the rocking of the tower triggered by the building displacements. In August 2016 a dynamic monitoring system was installed on the building, positioning accelerometers both at the last two floors of the structure and at the foundation level. The system allowed the recording of the building response to the aftershocks occurred during the monitoring period, and of the corresponding seismic input. Registrations are used to track of the modal parameters of the structure identified through input–output techniques (N4SID) in occurrence of seismic events, and through consolidated output-only techniques (SSI) in the periods between two subsequent events.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/293841

Assessment and Upgrading of Weakly Shear Reinforced Bridge Decks: A Case Study
Lecture Notes in Civil Engineering
Autore/i: Innocenzi, R. D.; Massa, G.; Nicoletti, V.; Carbonari, S.; Gara, F.; Dezi, L.
Editore: Springer Science and Business Media Deutschland GmbH
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: During the 60s and 70s many highway viaducts were built in Italy using simply supported prestressed beams, often adopting low shear reinforcement quantities following the prescriptions of the code in force at that time. Nowadays, according to the current assessment procedures at Ultimate Limit State (ULS), based on new criteria and increased traffic loads, shear reinforcements in exiting bridges are often not enough to face shear forces from vertical loads if the conventional truss resisting model is adopted. An alternative assessment procedure may consists in verifying prestressed single span members as elements without shear reinforcement in regions uncracked in bending. In this case, the shear resistance depends on the concrete tensile stress and the concrete compressive stress due to prestressing. With reference to a case study constituted by a prestressed deck of a highway viaduct, this paper shows the inadequacy of the shear capacity of the main girders subjected to traffic loads of the current codes. Subsequently, different upgrading strategies to improve the shear resistance are analyzed, including solutions that increase the bending capacity with external prestressing cables preventing the cracking in bending at ULS.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/294286

Expeditious Dynamic Tests for the Estimation of Infill Masonry Wall Stiffness
Lecture Notes in Civil Engineering
Autore/i: Nicoletti, V.; Arezzo, D.; Carbonari, S.; Gara, F.
Editore: Springer Science and Business Media Deutschland GmbH
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The importance of assessing the overall behaviour of buildings considering the contribution of non-structural infills has been nowadays widely recognised. Indeed, infills can trigger fragile mechanisms of structural members preventing the evolution of dissipative mechanisms and can play an important role in the verifications at damageability limit states, especially in the case of strategic structures for which often high performance levels are required, including the full operativity (i.e. absence of damage to both structural and non-structural members) after severe earthquakes, in order to guarantee the building occupancy during the emergency management. With reference to a case study, the paper presents a simplified approach for estimating the stiffness of masonry infill walls through expeditious dynamic impact tests on infills. The case study is constituted by a laboratory real-scale mock-up for which a complete dynamic identification is carried out before and after the realization of infill masonry walls. The adopted procedure is then validated through results from a refined finite element model of the mock-up in which infills are modelled adopting stiffnesses obtained from the proposed approach.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/293842

A simple methodology for the infill masonry wall stiffness estimation
COMPDYN Proceedings
Autore/i: Nicoletti, V.; Arezzo, D.; Carbonari, S.; Gara, F.
Editore: National Technical University of Athens
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The importance of assessing the overall dynamic behavior of buildings considering the contribution of infills is nowadays widely recognized considering that they play an important role in the verifications at damageability limit states and, at ultimate limit states, they can trigger fragile mechanisms of structural members preventing the evolution of dissipative ones. In addition, in case of strategic structures, for which often high performance levels are required such as the full operativity condition (i.e. absence of damage to both structural and non-structural components) after severe earthquake, the contribution of non-structural members should be necessarily included in the seismic assessment. The paper proposes a simplified procedure for estimating the stiffness of masonry infill walls through expeditious dynamic impact tests. Stiffness can be adopted to model infills into conventional 3-D finite element models of buildings. The procedure is validated by means of an experimental campaign carried out on a laboratory real-scale mock-up and then applied to a real infilled reinforced concrete frame building. Experimental results are compared with those obtained from refined finite element models including infills, proving the methodology reliability.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/293903

Some Considerations on the Expected Resonance Frequencies of Bridges During Proof Load Tests
Lecture Notes in Civil Engineering
Autore/i: Carbonari, S.; Martini, R.; Nicoletti, V.; Arezzo, D.; Gara, F.
Editore: Springer Science and Business Media Deutschland GmbH
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In case of bridges, static proof tests are mandatory to certify the compliance of the structural performance with that expected from the design model before the opening to traffic. Tests consist in progressively increase the load (by using fully loaded trucks) on one or more bridge spans and to monitor the structural response in terms of displacements, often obtained through topographic measurements. For new bridges, a linear structural response is expected while for existing ones some nonlinearities may also arise, for example in case of prestressed simply supported decks with I shaped or box girders of the 60s, for which the concrete cracking at midspan can be achieved, depending on the amount of prestress long term losses of tendons. The monitoring of the bridge resonance frequencies during the test may contribute to the interpretation of the overall test results, for both new and existing bridges. However, the estimation of the expected bridge dynamics during the proof load is not a simple task since it may be affected by bridge-truck interaction phenomena. To this purpose, a simple 2 degree of freedom model is adopted to qualitatively address the bridge-truck interaction phenomenon in the case of simply supported bridge decks. The model is adopted to perform a parametric investigation aimed to identify situations for which above interactions may be significant. The basic idea is to provide indications about the expected frequency changes during the tests with respect to the unloaded condition.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/294284

First results of the monitoring of the façade damage mechanism of the “Santa Maria in Via” Church in Camerino following the 2016 Central Italy Earthquake
Proceedings of the 10th International Conference on Structural Health Monitoring of Intelligent Infrastructure, SHMII 10
Autore/i: Arezzo, Davide; Nicoletti, Vanni; Leonardo, Cipriani; Carbonari, Sandro; Leoni, Graziano; Gara, Fabrizio
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The Italian architectural heritage is characterized by a very high seismic vulnerability, as demonstrated by damage occurred to buildings and churches following the main earthquakes of the last two decades. With reference to churches, even when total or partial collapses did not occur, damage mechanisms often activated, reducing the overall safety of the constructions. In order to prevent the evolution of damage, many immediate interventions and securing systems were installed and the need of controlling the evolution of the church damage recently become an issue of paramount importance. In this paper, the first results of the monitoring of the façade damage mechanism of the Santa Maria in Via church in Camerino (Central Italy) are reported and discussed. The church was strongly damaged after the Central Italy 2016 earthquake and consequently, an impressive securing system was built in order to prevent the damage evolution and to preserve the elements of architectural value. A preliminary identification of the dynamics of the whole church is performed through ambient vibration tests to get a benchmark through which possible evolutions in time of the modal parameters could be identified. Data herein presented refer to the first month of monitoring and to a small set of sensors already installed, including two accelerometers and two thermocouples positioned inside and outside the church. The complete dynamic monitoring system, which will allow to also capture variations of the system dynamics due to environmental conditions, is also described. The latter will be operative within the first months of the year 2021.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/296933

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

The tracking of modal parameters for a reinforced concrete building during low-medium intensity earthquakes
COMPDYN Proceedings
Autore/i: Arezzo, D.; Nicoletti, V.; Carbonari, S.; Gara, F.
Editore: National Technical University of Athens
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This paper presents the results of the dynamic monitoring carried out on a school building in central Italy during the seismic sequence following the first main shock of the 2016 Central Italy earthquake. The building is located in the historical centre of Camerino and consists of a reinforced concrete frame structure with masonry infill walls. The school, dating back to the 60s, underwent seismic retrofit in 2013 through the construction of 2 dissipative towers, a recent patented system for seismic protection of buildings. In August 2016 a dynamic monitoring system was installed on the building, positioning an array of accelerometers both on the top two floors of the structure and on the foundation level; this made it possible to record the building response to the aftershocks that occurred during the monitoring period, and the corresponding seismic input. The dynamic characteristics of the structure during the monitoring period are identified starting from the response of the structure subjected to the seismic swarm following the main event, and to the environmental vibrations between two subsequent events. Although during the monitoring days the building did not suffer any damage, the response of the structure proved to be nonlinear and strongly dependent on the amplitude of the accelerations to which it was subjected; in this work, a procedure to linearize the structural response and carry out the dynamic identification in terms of modal parameters starting from the non-stationary response of the structure is proposed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/293902

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

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

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

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

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

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

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

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

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