171 pubblicazioni classificate nel seguente modo:

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

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

Seismic reliability of Italian code-conforming bridges
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS
Autore/i: Franchin, P.; Baltzopoulos, G.; Biondini, F.; Callisto, L.; Capacci, L.; Carbonari, S.; Cardone, D.; Dall'Asta, A.; Flora, A.; Gorini, D. N.; Marchi, A.; Noto, F.; Perrone, G.; Iervolino, I.
Classificazione: 1 Contributo su Rivista
Abstract: Seismic reliability assessment of selected bridge structures code-conforming with respect to the current Italian practice is carried out. Two viaducts, tall and shallow, and two highway overpasses, with traditional seat-type or integral abutments, are considered. Each structure is ideally placed at three reference sites, that is, Milan, Naples and L'Aquila, characterised by low, moderate and high seismic hazard, respectively. At each site, a soil profile representative of typical local conditions is defined for foundation design, site response analysis and soil-structure interaction modelling. Probabilistic seismic hazard is used in conjunction with multiple-stripe non-linear dynamic analysis, featuring conditional-spectrum compatible ground motions, to establish the failure rate with respect to two purposely defined and functionality-related performance levels. It is confirmed the decreasing seismic reliability with increasing design seismic action, already observed for other structural types, and it is shown that integral abutment overpasses tend to be more reliable than traditional ones, even seismically isolated ones. The results are of larger interest given the closeness of the Italian code to the Eurocode.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/325833

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

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

Static and dynamic testing of the cable-stayed bridge on the Saline River in the Abruzzo reigion, Italy
Proceedings of the 11th International Conference on Short and Medium Span Bridges
Autore/i: Innocenzi, Raoul; Carbonari, Sandro; Gara, Fabrizio; Dezi, Luigino
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The paper presents the results of static and dynamic tests carried out during the final testing of the medium-span cable-stayed bridge recently build over the river Saline in the Abruzzo Region (Italy). The bridge has a steel-concrete composite deck of three spans of 42.6, 103.4 and 42.6 m for a total length of 188.6 m. During the different phases of the load tests, several response parameters were monitored to evaluate the overall static and dynamic behavior of the bridge, including deflections of the main girders, tensile stresses of strands, pylons and supports displacements, modal parameters, evaluated through Ambient Vibration Tests (AVTs), and air and road pavement temperature. Due to the deck flexibility, AVTs in both loaded and unloaded configurations, highlighted the role of vehicle loads on the bridge dynamics.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/310054

Seismic response of large offshore wind turbines on monopile foundations including dynamic soil–structure interaction
OCEAN ENGINEERING
Autore/i: Padron, L. A.; Carbonari, S.; Dezi, F.; Morici, M.; Bordon, J. D. R.; Leoni, G.
Classificazione: 1 Contributo su Rivista
Abstract: This paper presents the results of a study on the dynamic and seismic response of the support structures of three reference Offshore Wind Turbines (OWT) of increasing rated power, founded to the seabed through monopile foundations. Thus, the structural behaviour of the NREL 5 MW, IEA Wind 10 MW and IEA Wind 15 MW reference OWTs under seismic input is analysed. To do so, a model based on the aero-hydro-servo-elastic OpenFAST open-software code, modified to include dynamic Soil–Structure Interaction (SSI) and input ground motion, is employed. Dynamic SSI phenomena are incorporated through lumped parameter models fitted to the impedances computed using an advanced boundary elements–finite elements model of the soil–foundation system in which the monopile is discretized as a steel pipe buried in the unbounded seabed. The fore–aft and side-to-side responses of the systems are computed under power production, parked and emergency shutdown operating conditions considering different earthquakes and arrival times. It is found that even low and moderate intensity earthquakes can produce significant increases in the structural demands of large OWTs. There exists a clear tendency for SSI to be beneficial when the size of the OWT increases.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/303980

Preface to special issue on modelling and assessment of soil-structure interaction effects on the dynamics of structures
Special issue: Modelling and assessment of soil-structure interaction effects on the dynamics of structures
Autore/i: Carbonari, S; Dezi, F; Padron, La; Zimmaro, P
Editore: SPRINGER
Luogo di pubblicazione: VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS
Classificazione: 2 Contributo in Volume
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/303981

Winkler model for predicting the dynamic response of caisson foundations
EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS
Autore/i: Carbonari, S.; Bordon, J. D. R.; Padron, L. A.; Morici, M.; Dezi, F.; Aznarez, J. J.; Leoni, G.; Maeso, O.
Classificazione: 1 Contributo su Rivista
Abstract: The paper presents a Winkler-based numerical model for the analysis of the dynamic response of caisson foundations. The model allows the evaluation of the impedance functions and of the foundation input motion (FIM), which can be used in the framework of the substructure approach to compute inertial soil-foundation superstructure interaction analyses. In addition, kinematic stress resultants due to seismic shear waves propagating into the soil can be estimated. The caisson is modelled as a Timoshenko beam and the soil-caisson interaction forces are derived from the analyses of the plane-strain vibration problem of an annular rigid ring embedded into the soil. The problem solution is obtained in the frequency domain exploiting the finite element approach and generic soil stratigraphies can be considered in the applications. The model, which is characterised by a very low computational effort, is validated by performing a parametric investigation, comparing results with those obtained from more rigorous BEM-FEM models of the soil-caissons systems. Finally, some applications to real caisson foundations of offshore wind turbines (OWTs) are shown to demonstrate the model accuracy in capturing the seismic response of the foundations obtained from more rigorous models.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/304739

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

A probabilistic investigation on the dynamic behaviour of pile foundations in homogeneous soils
BULLETIN OF EARTHQUAKE ENGINEERING
Autore/i: Minnucci, L.; Morici, M.; Carbonari, S.; Dezi, F.; Gara, F.; Leoni, G.
Classificazione: 1 Contributo su Rivista
Abstract: Soil-structure interaction is a complex problem to address in structural design due to difficulties related to the modelling of the soil-foundation behaviour, which is frequency-dependent and affected by uncertainties. The substructure method is an efficient approach to include the soil-foundation behaviour in the superstructure response, since it allows addressing separately the soil-foundation and the superstructure analysis exploiting different tools and expertise. A deterministic approach is usually adopted for the soil-foundation system analysis selecting properties of foundation and soil based on an engineering judgment, despite uncertainties due to the intrinsic variability of soil parameters are largely recognised by both scholars and practitioners, as well as confirmed by experimental campaigns and laboratory tests. This paper presents a probabilistic perspective of the dynamic behaviour of pile foundations in homogeneous soils, focusing on the effects of the uncertainties in: (i) the frequency-dependent impedance functions; and (ii) the kinematic response factors necessary to derive the foundation input motion from the free-field motion. Single piles and square pile groups are considered. Uncertainties are described through the probabilistic distributions of parameters governing the soil-foundation dynamic response, while the samples are generated using the quasi-random sampling technique. Probabilistic analyses are performed utilizing an efficient numerical model that has been developed, and the variability of the output quantities is presented and discussed. The latter reveals to be strongly affected by frequency. In addition, sensitivity analyses are performed to investigate the influence of each variable uncertainty on the system response. The response quantities are highly sensitive to the shear wave velocity while the soil density and the pile elastic modulus may have a significant role, depending on the foundation layout.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/306183

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

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

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

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

Innovative Fragility-Based Method for Failure Mechanisms and Damage Extension Analysis of Bridges
INFRASTRUCTURES
Autore/i: Minnucci, L.; Scozzese, F.; Carbonari, S.; Gara, F.; Dall'Asta, A.
Classificazione: 1 Contributo su Rivista
Abstract: The seismic assessment of existing bridges is of the utmost importance to characterise the main structural deficiencies, estimate the risk, prioritise retrofit interventions, or estimate losses and repair costs in case of earthquakes. The above tasks require information on the damage mechanisms likely to occur as well as on the damage extent over the structure. Such types of information are generally not provided by classical fragility analysis, which is mainly focused on the evaluation of the global performance of the bridge. In this paper, a systematic probabilistic methodology for the evaluation of bridge fragility is proposed. The methodology aims at offering insight into the failure mechanisms most likely to occur and the evolution and extent of damage within the bridge structure. First, a mathematical description of the proposed analysis methods is given, then an application to a realistic case study—a reinforced concrete multi-span simply supported deck link-slab bridge—is provided to illustrate the applicability of the tool. A nonlinear 3D finite element model is developed, and a multiple-stripe (nonlinear dynamic) analysis is performed by using a stochastic bidirectional seismic input. The results highlight the suitability of the proposed methodology to reveal the main structural deficiencies, the relations among different failure mechanisms (involving piers, bearings, abutments, etc.), and the expected damage extent.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/306621

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

Field tests and numerical analysis of the effects of scour on a full-scale soil–foundation–structural system
JOURNAL OF CIVIL STRUCTURAL HEALTH MONITORING
Autore/i: Tubaldi, E.; Antonopoulos, C.; Mitoulis, S. A.; Argyroudis, S.; Gara, F.; Ragni, L.; Carbonari, S.; Dezi, F.; Vratsikidis, A.; Pitilakis, D.; Anastasiadis, A.
Classificazione: 1 Contributo su Rivista
Abstract: Scour is the prevailing cause of bridge failure worldwide, leading not only to traffic disruption, but also to social and economic losses and even to casualties. Many vibration-based monitoring techniques have been proposed for identifying the scour location and extent, based on the evaluation of the changes of the bridge modal properties due to scour. This study describes the experimental and numerical research carried out to investigate the effects of scour on the dynamic properties of structures with shallow foundations. Although these are the most vulnerable ones, they have received less attention compared to structures founded on pile foundations. To fill some existing knowledge gaps, field experiments were carried out on EuroProteas, a structural prototype with shallow foundation that was subjected to increasing levels of scour. The changes of the dynamic properties of the system are evaluated by postprocessing the ambient vibration recordings and by developing various models of the soil–foundation–structural system with different descriptions of the soil–structure interaction problem. The study results shed light on the effects of scour on systems with shallow foundations and on the accuracy of alternative modelling approaches. They are presented here to inform the development and validation of vibration-based techniques and modelling strategies for bridge scour identification.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/306181

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

Correction to: A probabilistic investigation on the dynamic behaviour of pile foundations in homogeneous soils
BULLETIN OF EARTHQUAKE ENGINEERING
Autore/i: Minnucci, L.; Morici, M.; Carbonari, S.; Dezi, F.; Gara, F.; Leoni, G.
Classificazione: 1 Contributo su Rivista
Abstract: Due to proofing error, author surnames were reversed and should correctly read as: Lucia Minnucci, Michele Morici, Sandro Carbonari, Francesca Dezi, Fabrizio Gara, Graziano Leoni Original article has been updated.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/306182

A methodology for the identification of physical parameters of soil-foundation-bridge pier systems from identified state-space models
ENGINEERING STRUCTURES
Autore/i: Carbonari, S.; Dezi, F.; Arezzo, D.; Gara, F.
Classificazione: 1 Contributo su Rivista
Abstract: A methodology for the identification of the physical parameters of a model describing the transverse dynamics of soil-foundation-pier systems founded on piles is presented in this paper, starting from identified state-space models of the systems obtained from results of dynamic experimental tests and identification techniques available in the literature. By assuming the order of the model to be compliant with that of a numerical one suitably developed to capture the dynamics of the bridge pier, the procedure allows the identification of the stiffness, mass and damping matrices of the analytical model from which the physical parameters of the real system (e.g. masses, pier stiffness matrix and soil-foundation impedance) can be extracted by directly comparing the components of the identified and analytical matrices. The procedure allows the direct definition of the numerical model that best fits the experimental data without the need of any model calibration, and permits the identification of the soil-foundation compliance taking into account its intrinsic frequency-dependent behaviour. Firstly, the dynamics of the analytical model is formulated adopting the continuous-time first-order state-space form. The model includes the frequency-dependent behaviour of the soil-foundation system through the introduction of a lumped parameter model able to reproduce the typical soil-foundation impedances of pile foundations. Then, an identification strategy of the physical parameters of a generic realistic soil-foundation-pier system is proposed starting from the discrete-time state-space model identified from dynamic tests. The procedure is illustrated with some applications, simulating results of forced vibration and ambient vibration tests executed on a known system whose parameters are then identified according to the proposed approach. The procedure revealed to be effective to identify the stiffness, mass and damping matrixes of the known system, and consequently its physical parameters.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295702

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

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

Dynamic behavior of soil-foundation-structure systems subjected to scour
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
Autore/i: Antonopoulos, C.; Tubaldi, E.; Carbonari, S.; Gara, F.; Dezi, F.
Classificazione: 1 Contributo su Rivista
Abstract: Earthquake and scouring are the leading causes of bridge failure worldwide, resulting not only in casualties and fatalities but also in enormous societal and economic losses. A great number of bridges in earthquake-prone countries cross rivers and have shallow foundations, which renders them highly vulnerable to the combined effects of earthquake and flood-induced scour. Thus, the research on the dynamic response of bridges with shallow foundations under scour and earthquake hazards is timely and imperative. This study investigates the problem through the development of a numerical model for evaluating the effect of scour on the impedance functions of a massless rigid strip foundation resting on a homogenous elastic half-space. The developed impedance functions are then used in an extensive parametric study analyzing the changes of the fundamental frequency of bridge piers for different combinations of the geometrical and mechanical properties of the soil-structure-foundation system. The study results shed light on the effects of scour on the dynamic properties and fundamental frequency of vibration of bridges with shallow foundations and have important implications on the development of inverse techniques for scour identification based on the evaluation of the changes in the bridge modal properties.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/293282

Seismic Retrofit Assessment of a School Building through Operational Modal Analysis and f.e. Modeling
JOURNAL OF STRUCTURAL ENGINEERING
Autore/i: Gara, F.; Carbonari, S.; Roia, D.; Balducci, A.; Dezi, L.
Classificazione: 1 Contributo su Rivista
Abstract: The paper deals with the dynamic characterization of a reinforced concrete (RC) frame school building in central Italy before and after the seismic retrofitting, obtained by coupling the building with an innovative patented seismic dissipative protection system. Before the retrofit, ambient vibration tests were performed to evaluate frequencies and mode shapes for developing finite-element (f.e.) models describing the school dynamic behavior in operational conditions. Several finite-element models with increasing level of detail are presented, from the bare frame model, based on the assumptions and simplifications usually adopted for design purposes, to an upgraded model taking account of secondary and nonstructural elements (e.g., internal and external walls, screeds, roofing, floor tiles, and plasters) as well as the interaction between structure and retaining walls. The latter was used to develop the design model of the seismic retrofitting system, which aims to assure the immediate occupancy of the building in the case of severe earthquakes limiting damage to nonstructural components. Tests were repeated after the retrofit to check consistency with numerical design predictions. Comparisons between experimental and numerical modal parameters are shown discussing the usefulness of ambient vibration tests.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/285066

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

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

Post-Earthquake Damage and Vulnerability Assessment of Churches in the Marche Region Struck by the 2016 Central Italy Seismic Sequence
INTERNATIONAL JOURNAL OF ARCHITECTURAL HERITAGE
Autore/i: Canuti, C.; Carbonari, S.; Dall'Asta, A.; Dezi, L.; Gara, F.; Leoni, G.; Morici, M.; Petrucci, E.; Prota, A.; Zona, A.
Classificazione: 1 Contributo su Rivista
Abstract: This paper analyses the observational damage from post-earthquake investigations carried out on churches of the Marche Region struck by the 2016 Central Italy seismic sequence. Such seismic activity seriously damaged many historical buildings and particularly churches, due to their intrinsic inability to develop an efficient box-like resisting mechanism. After the mainshocks, teams of structural engineers were involved in the assessment of damage of churches and in the evaluation of their usability. Collected data are processed in this work to give insight into the occurred damage and to evaluate the vulnerability of the religious buildings of the Region. To this purpose, an architectural background is firstly provided to allow for a classification of the sample, then, the most recurring damage mechanisms are identified, and a global damage index of each church is computed. The distribution of the damage over the Region is commented, as a function of the macro-seismic intensity and other important factors affecting the seismic response. Finally, the overall damage of the sample is compared to that estimated through empirical models available in the literature and comparisons with the results of previous studies are provided.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269907

Influence of the piers' height on the fragility assessment of Italian R.C. Link slab bridges
COMPDYN Proceedings
Autore/i: Minnucci, L.; Scozzese, F.; Dall'Asta, A.; Carbonari, S.; Gara, F.
Editore: National Technical University of Athens
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Recent seismic events occurred in Central Italy drew the attention towards the resilience of the Italian road network, which is characterized by a significant number of old reinforced concrete bridges and viaducts. In this context, the fragility assessment of existing bridges is crucial, since their collapse or loss in functionality after earthquakes may lead to significant economic and social consequences. This work focuses on the fragility assessment of reinforced concrete multi-span continuous bridges, which is a widespread structural typology in Italy. The study aims to individuate fragilities relevant to both local and global mechanisms, considering bridge components such as piers, bearings and deck members, in order to highlight the most vulnerable ones compromising the whole structural response under the seismic action. A probabilistic framework is developed considering both the site-dependent seismic hazard and the most important Engineering Demand Parameters (EDPs) characterizing the structural response. The first one accounts for the record-to-record variability as well as the parameters governing the seismic scenario in which the structure is located, while the latter ones are individuated depending on the structural typology and the identified vulnerabilities. Multiple Stripe Analyses are performed with the aim of providing insights about the seismic response of the bridge class at hand and of furnishing the fragility curves for all the response parameters relevant for the structural system. Starting from a real case study located in Centre Italy, a couple of reinforced concrete bridge models is developed in order to consider the influence of different heights for the piers and to provide a forecast for the structural behaviour of the selected bridge class. The models are able to capture the failure mechanisms most likely to occur. Performance thresholds are chosen for each bridge component considering the relevant limit state demands according to the current codes and literature. As a result, fragility curves provide useful insights about the main structural deficiencies of the system at hand.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/293901

Finite elements for higher order steel–concrete composite beams
APPLIED SCIENCES
Autore/i: Gara, F.; Carbonari, S.; Leoni, G.; Dezi, L.
Classificazione: 1 Contributo su Rivista
Abstract: This paper presents finite elements for a higher order steel–concrete composite beam model developed for the analysis of bridge decks. The model accounts for the slab–girder partial interaction, the overall shear deformability, and the shear‐lag phenomenon in steel and concrete components. The theoretical derivation of the solving balance conditions, in both weak and strong form, is firstly addressed. Then, three different finite elements are proposed, which are characterised by (i) linear interpolating functions, (ii) Hermitian polynomial interpolating functions, and (iii) interpolating functions, respectively, derived from the analytical solution expressed by means of exponential matrices. The performance of the finite elements is analysed in terms of the solution con-vergence rate for realistic steel–concrete composite beams with different restraints and loading con-ditions. Finally, the efficiency of the beam model is shown by comparing the results obtained with the proposed finite elements and those achieved with a refined 3D shell finite element model.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/286916

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

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

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

Damage Detection of Post-tensioned Cables in Existing Bridges with Digital Radiography
Lecture Notes in Civil Engineering
Autore/i: Innocenzi, R. D.; Pigliapoco, G.; Carbonari, S.; Gara, F.; Dezi, L.
Editore: Springer Science and Business Media Deutschland GmbH
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The evaluation of the residual efficiency of post-tensioned cables in existing prestressed concrete bridges is a very challenging and important task for the structural safety assessment. Indeed, some collapses of this kind of bridges occurred recently in Italy were attributed to the failure of cables. However, non-destructive tests for the damage detection of cables are not yet effective and well-established in the literature. The paper presents a new testing technique, based on Digital Radiography (DR), to check the integrity of post-tensioned cables in beam webs by means of radiographic images able to detect both the corrosion of wires or strands and the grouting consistency in ducts. The DR technique has been recently applied in two highway viaducts and validated through local destructive core samples, detecting the real state of cables. The results of this testing campaign are widely discussed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/294287

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

Influence of the Deck Length on the Fragility Assessment of Italian R.C. Link Slab Bridges
Lecture Notes in Civil Engineering
Autore/i: Minnucci, L.; Scozzese, F.; Dall'Asta, A.; Carbonari, S.; Gara, F.
Editore: Springer Science and Business Media Deutschland GmbH
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This work focuses on the fragility assessment of reinforced concrete multi-span continuous bridges, which is a widespread structural typology in Italy, with the aim of investigating the peculiar vulnerabilities of the bridge class under investigation, the reinforced concrete link slab jointless bridges. The need for a deeper study on the topic derives from the wide diffusion of such typology on the Italian road network, which has been recently struck by earthquakes and needs intervention works for the safety of old bridges and viaducts. Starting from a real case study located in Centre Italy, a couple of reinforced concrete bridge case studies is chosen in order to consider the influence of different length for the deck and to provide a forecast for the structural behaviour of the selected bridge class. The associated numerical models are able to capture the failure mechanisms most likely to occur, and a dedicated modelling strategy is developed to capture the potential failure on the kinematic links on the superstructure. A probabilistic framework is developed considering both the site-dependent seismic hazard, which accounts for the parameters characterizing a medium seismicity level area as well as the record-to-record variability, and the demand parameters related to the examined vulnerabilities. Seismic analyses are carried out through the Multiple Stripe Analysis methodology to furnish the fragility curves for all the response parameters relevant for the structural system. Performance thresholds are chosen for each bridge component according to the current codes and literature. As a result, fragility curves provide useful insights about the main structural deficiencies of the system at hand in order to evaluate possible intervention strategies against social and economic losses.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/294285

Influence of scour on dynamic impedances of bridge shallow foundations
COMPDYN Proceedings
Autore/i: Antonopoulos, C.; Tubaldi, E.; Carbonari, S.; Gara, F.; Dezi, F.
Editore: National Technical University of Athens
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Many bridges in earthquake-prone countries cross waterways and have foundations in riverbeds, and thus are exposed to flood, which may cause scour and a change of the bridge dynamics. The present study illustrates a modeling strategy for investigating numerically the influence of scour on the dynamic behaviour of bridges with scoured shallow foundations. The proposed strategy is based on the evaluation of the impedance functions of a massless rigid foundation resting on an elastic half-space under increasing depths of scour. The derived impedance functions are used to evaluate the effects of scour on the dynamic behaviour of a Soil-Foundation-Structure system representative of a bridge pier. In particular, the changes in the fundamental vibration period due to scour are investigated. The results of the study can be used for developing vibration-based scour detection techniques and for investigating the seismic response of scoured bridges.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/293904

Static and dynamic testing of the “Filomena Delli Castelli” bridge
Belgian, Dutch and French National Groups of IABSE – Young Engineers Colloquium
Autore/i: Innocenzi, RAOUL DAVIDE; Carbonari, Sandro; Gara, Fabrizio; Dezi, Luigino
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The paper describes the static and dynamic testing of the “Filomena Delli Castelli”cable-stayed bridge over the Saline River, in the Pescara province (Italy), having main span of 103.4 m and total length of 188.6 m.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/291654

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

Numerical and simplified methods for soil-pile interaction analysis
GEOTECHNICAL ENGINEERING
Autore/i: Dezi, F.; Carbonari, S.; Morici, M.; Leoni, G.
Classificazione: 1 Contributo su Rivista
Abstract: The paper presents a review of the analytical and numerical procedures developed by the authors for the dynamic analysis of soil-pile foundation systems subjected to the propagation of seismic waves in the soil. Inclined and vertical single piles and groups constituted by piles with a generic inclination are addressed. For the former, an analytical approach based on the beam on dynamic Winkler foundation approach is adopted; the pile is modelled as a Euler-Bernoulli beam and the soil-pile interaction is captured by defining soil impedances relevant to the harmonic vibrations of rigid disks available in the literature. The coupled flexural and axial behaviour of the pile is solved analytically exploiting exponential matrices. The pile group dynamic problem is similarly formulated but the solution is achieved exploiting the finite element approach. Besides numerical models, simplified approaches based on static equivalent methods and simplified formulas are also addressed to estimate the maximum kinematic stress resultants on vertical piles subjected to lateral seismic excitations. The reliability of the presented tools in capturing the dynamic stiffness and the overall kinematic response of pile foundations is shown by comparing results with those available in the literature or achieved through refined finite element models. From an engineering point of view, the proposed approaches assure a sufficient accuracy and may substitute refined computational demanding numerical models.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/283312

Dynamic performance of a full-scale micropile group: Relevance of nonlinear behaviour of the soil adjacent to micropiles
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
Autore/i: Capatti, M. C.; Dezi, F.; Carbonari, S.; Gara, F.
Classificazione: 1 Contributo su Rivista
Abstract: An extensive experimental in-situ campaign of dynamic tests carried out on a full-scale 2 x 2 group of inclined injected micropiles in alluvial soils is described in this paper. The campaign includes ambient vibration and impact load tests to investigate the dynamic behaviour of the soil-micropile system in the small strain range, and forced vibration tests to investigate the performance of the system in the nonlinear field. Accelerometers and geophones are adopted to acquire the dynamic response on the cap and the soil nerby the cap, while strain gauges are installed along the shaft of one micropile to capture the local curvatures and deflections. The influence of the micropile inclination on the translational and rotational behaviour of the group is evaluated. Moreover, the evolution of degradation phenomena such as the gap opening and slippage at the soil-micropile interface and the radial cracking of soil surrounding micropiles, are recognized, critically commenting the relevant effects on the fundamental frequencies and damping ratios of the system.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/270855

Benefits of inclined pile foundations in earthquake resistant design of bridges
ENGINEERING STRUCTURES
Autore/i: Gonzalez, F.; Carbonari, S.; Padron, L. A.; Morici, M.; Aznarez, J. J.; Dezi, F.; Maeso, O.; Leoni, G.
Classificazione: 1 Contributo su Rivista
Abstract: This paper studies the effects of the use of inclined pile foundations on the seismic response of bridges, and shows that this type of foundation is able to promote significant reductions in the ductility demand of reinforced concrete piers. To this end, a set of nine multi-span roadway viaducts with different pier heights and span lengths is defined. Each configuration is designed and dimensioned in detail following a displacement-based approach, considering both linear and non-linear expected behaviours and assuming different target ductilities for piers. The systems are assumed to be founded on a specific soil profile, and suitable pile foundation layouts and dimensions are determined for each case, with four different pile rake angles (including the vertical case) in each configuration. Soil-structure interaction phenomena are incorporated through the corresponding frequency-dependent impedance functions and kinematic interaction factors. The transverse response of the viaducts, subject to a set of seven suitable scaled real accelerograms, is computed and analysed making use of a substructuring approach and non-linear time-domain analysis in which a lumped parameter model is adopted to represent the foundation response. Results, presented not only in terms of ductility demand but also of energy dissipated in the structural system by damping or by yielding, suggest that inclined piles are clearly beneficial to the seismic response of bridges, contributing to significant reductions in ductility demand due to the particular kinematic seismic response of this type of foundations and associated reductions in the input seismic energy to the system.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/271995

Field tests on a soil-foundation-structure system subjected to scour
Atti del XVIII Convegno ANIDIS L'ingegneria sismica in Italia
Autore/i: Tubaldi, Enrico; Lupo, Rosa; Mitoulis, Stergios; Argyroudis, Sotiris; Gara, Fabrizio; Ragni, Laura; Carbonari, Sandro; Dezi, Francesca
Editore: Pisa University Press srl
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Earthquakes and foundation scour are the major causes of bridge failure worldwide. Many bridges in earthquake-prone countries have shallow foundations, whose stability and seismic vulnerability can be significantly undermined by flood-induced scour. This article provides the first results of the “DYMOBRIS” project (DYnamic identification and MOnitoring of scoured BRIdgeS under earthquake hazard), a H2020-SERA EU-funded project aiming at i) developing a methodology for non-invasive detection of scour in bridges with shallow foundations based on vibration monitoring, and ii) quantifying the effects of scour on the seismic vulnerability of these Soil-Foundation-Structure (SFS) systems. The experimental campaign involves various tests, from ambient vibration to force vibration, on the EuroProteas prototype under different scour conditions. The preliminary finite element models developed for defining the scour profile to be imposed in the in-field tests are presented here, together with some results concerning the effects of scour on the SFS dynamic properties.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269908

Risultati del monitoraggio dinamico di un edificio scolastico a Camerino a valle del sisma del centro Italia dell’agosto 2016
Atti del XVIII Convegno ANIDIS L'ingegneria sismica in Italia
Autore/i: Arezzo, Davide; Speranza, Elisa; Carbonari, Sandro; Gara, Fabrizio
Editore: Pisa University Press srl
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Il lavoro presenta i risultati del monitoraggio dinamico di un edificio scolastico situato a Camerino (MC), durante la sequenza sismica che ha colpito l’Italia centrale nel 2016. L’edificio ospita il liceo Classico e Scientifico “Varano” ed è situato nel centro storico di Camerino; si tratta di un fabbricato con struttura a telaio in cemento armato e tamponature in laterizio realizzato negli anni ’60 e adeguato sismicamente nel 2013 con il sistema delle Torri Dissipative. Nel 2016, a valle del sisma del 24 agosto, è stato installato sull’edificio un sistema di monitoraggio dinamico costituito da accelerometri posizionati agli ultimi due piani della struttura e a livello delle fondazioni. Le registrazioni del moto alla base e della risposta dell’edificio ai piani superiori per effetto dei numerosi eventi sismici successivi al sisma principale e delle vibrazioni ambientali nei periodi di intervallo tra i sismi, hanno consentito di identificare i parametri modali grazie a tecniche input-output (N4SID), in occorrenza degli eventi sismici, e alle consolidate tecniche output-only (SSI), nei periodi di quiete. Ciò ha consentito di cogliere l’evoluzione delle caratteristiche dinamiche dell’edificio durante lo sciame sismico.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269911

Una formulazione approssimata delle impedenze e del moto di fondazione per l’analisi inerziale di strutture fondate su pali
Atti del XVIII Convegno ANIDIS L'ingegneria sismica in Italia
Autore/i: Morici, Michele; Minnucci, Lucia; Carbonari, Sandro; Dezi, Francesca; Leoni, Graziano
Editore: Pisa University Press srl
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Questo lavoro presenta una procedura semplificata per l’analisi di interazione terreno-struttura nel dominio del tempo di strutture fondate su pali. La procedura si basa sull’utilizzo di un modello a parametri concentrati per l’approssimazione della rigidezza dinamica del sistema fondazione-terreno che risulta dipendente dalla frequenza; l’approccio può essere facilmente implementato in software commerciali per l’analisi lineare e non lineare di strutture e permette di tener conto del comportamento traslazionale, rotazionale e roto-traslazionale di fondazioni profonde in funzione della frequenza di eccitazione e delle caratteristiche del deposito. Per la stima dei parametri del modello sono state utilizzate espressioni analitiche calibrate con regressioni non lineari ai minimi quadrati sulla base di dati ottenuti da una esaustiva analisi parametrica non dimensionale. Le formule, che permettono di definire modelli a parametri concentrati rappresentativi di fondazioni quadrate con differente numero di pali in rigidi depositi di varia natura, possono essere direttamente adottate per eseguire analisi inerziali delle sovrastrutture includendo il comportamento dinamico del sistema terreno-fondazione. Alcune applicazioni su pile da ponte singole sono in ultimo presentate con il fine di mostrare l’utilizzo pratico della procedura proposta. I risultati dimostrano le potenzialità dell’approccio nel cogliere la risposta dinamica attesa delle strutture, valutata attraverso una analisi di interazione terreno-struttura più rigorosa.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269913

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

Local failure mechanisms of existing steel-concrete composite decks
Atti del XXVII CONGRESSO C.T.A.
Autore/i: Minnucci, Lucia; Carbonari, Sandro; Dezi, Luigino; Gara, Fabrizio; Dall'Asta, Andrea
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The design of Steel-Concrete Composite (SCC) bridges is usually oriented to the solution of global problems, governed by strength and ductility issues of the whole structure, while minor attention is generally given to local effects, associated with the transfer mechanisms of inertia forces from decks to substructures. However, local failure mechanisms of the deck may be of importance since they may compromise the overall response of the bridge, especially for existing bridges, designed ac-cording to lower seismic actions compared to those defined by modern codes. In this paper, the seismic response of an existing SCC bridge is investigated, focusing on the role of local failure mechanisms of the deck on the overall response of the bridge. Two local paths for the seismic action are analyzed: the first involves the shear connection through which inertia forces act-ing at the level of the concrete slab are firstly transferred to steel members; the second is represented by truss cross-beams at supports, one of the most widespread typologies for existing SCC decks, through which the shear forces are transferred to bearings and substructures. Results of seismic analyses on the selected case study are shown and discussed, highlighting the vulnerabilities of the investigated local components.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/273425

The significance of soil-foundation compliance on the dynamic identification of the Chiaravalle viaduct
Atti del XVIII Convegno ANIDIS L'ingegneria sismica in Italia
Autore/i: Carbonari, Sandro; Dezi, Francesca; Gara, Fabrizio; Leoni, Graziano
Editore: Pisa University Press srl
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The paper addresses the significance of soil-structure interaction on the dynamic behaviour of the “Chiaravalle viaduct”, based on ambient vibration measurements and numerical simulations through a finite element model. The viaduct is located in Central Italy and is founded on piles in an eluvial-colluvial soil deposit. Experimental modal properties are evaluated by means of the operational modal analysis on accelerometric data, and the role of soil-structure interaction in the interpretation of tests is identified by means of a refined finite element model of the viaduct. In the soil-structure interaction models the local site conditions in correspondence of each bridge pier (resulting from geotechnical and geophysical investigations) are taken into account in the definition of the soil-foundations impedances. Comparisons between the experimental and numerical results highlight the role of the pile-soil-pile interaction, the radiation problem, the pile cap embedment and the variability of the soil stratigraphy along the longitudinal direction of the viaduct in the interpretation of the experimental data.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269912

Evaluation of fragility curves of a reinforced concrete viaduct in Central Italy: a preliminary analysis
Atti del 1st fib Italia YMG Symposium on Concrete and Concrete Structures
Autore/i: Minnucci, Lucia; Scozzese, Fabrizio; Carbonari, Sandro; Dall’Asta, Andrea; Gara, Fabrizio
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Recent seismic events occurred in Central Italy drew the attention towards the resilience of the Italian road network, which is characterised by a significant number of old reinforced concrete bridges and viaducts. In this context, the fragility assessment of existing bridges is crucial, since their collapse or loss in functionality after earthquakes may lead to significant economic and social consequences. As a preliminary study oriented to characterizing the fragility level of the Italian bridge heritage, this work focuses on the real case study of the Chiaravalle viaduct, located in Centre Italy, which may be representative of a widespread class of reinforced concrete bridges in Italy. The viaduct is entirely characterized by a reinforced concrete structure, with a link continuous slab on simply supported V-shaped girders. After a preliminary study on the current structural health of the bridge, a numerical model is developed in order to capture the failure mechanisms most likely to occur. Fragility curves, built by accounting for all the relevant demand parameters and limit states, provide useful insights about the main structural deficiencies of the system at hand.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/275315

Preliminary probabilistic assessment of the seismic response of link slab viaducts
Atti del XVIII Convegno ANIDIS L'ingegneria sismica in Italia
Autore/i: Minnucci, Lucia; Scozzese, Fabrizio; Carbonari, Sandro; Dall’Asta, Andrea; Gara, Fabrizio
Editore: Pisa University Press srl
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Recent seismic events occurred in Central Italy drew the attention towards the resilience of the Italian road network, which is characterised by a significant number of old reinforced concrete bridges and viaducts. In this context, the fragility assessment of existing bridges is crucial, since their collapse or loss in functionality after earthquakes may lead to significant economic and social consequences. As a preliminary study oriented to characterizing the fragility level of the Italian bridge heritage, this work focuses on the real case study of the Chiaravalle viaduct, located in Central Italy, which may be representative of a widespread class of reinforced concrete bridges in Italy. The viaduct is a continuous multi-span bridge consisting of precast simply supported V-shaped beams connected by a continuous upper slab. A numerical model is developed in order to capture the failure mechanisms most likely to occur for this bridge typology subjected to seismic actions. A probabilistic assessment of the seismic response of the bridge is carried out by performing multiple stripe analysis (MSA), and a preliminary interpretation of the results is provided. Future studies will be aimed to the development of fragility curves, by accounting for all the relevant demand parameters and limit states.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269910

Seismic response of bridge piers on pile groups for different soil damping models and lumped parameter representations of the foundation
EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS
Autore/i: González, Francisco; Padrón, Luis A.; Carbonari, Sandro; Morici, Michele; Aznárez, Juan J.; Dezi, Francesca; Leoni, Graziano
Classificazione: 1 Contributo su Rivista
Abstract: This paper presents a wide parametric study aimed at elucidating the influence, on the computed seismic response of bridge piers, of two related aspects of the model: (1) the adoption of the classical hysteretic or the causal Biot's damping models for the soil and (2) the use of two different lumped parameter models of different complexity and accuracy to approximate the impedances of the pile foundation. A total of 2072 cases, including different superstructures, pile foundations, soil deposits, and seismic input signals, are studied. The results are presented so that the influence of the different parameters involved in the analysis can be assessed. From an engineering point of view, both lumped parameter models provide, in general, sufficiently low errors. The choice of the most adequate model for each case will depend not only on the configuration of the structure and the soil‐foundation system but also on the assumed soil damping model, whose influence on the computed seismic responses is relevant in many cases. The nonphysical behaviour provided by the classical hysteretic damping model for the soil at zero frequency generates issues in the process of fitting the impedance functions. It is also found that larger deck displacements are predicted by Biot's model due to the higher damping at low frequencies provided by the classical hysteretic damping model.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/261977

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

A performance-based approach for the design of coupled dolphin-fender berthing structures
MARINE STRUCTURES
Autore/i: Carbonari, Sandro; Antolloni, Giulia; Gara, Fabrizio; Lorenzoni, Carlo; Mancinelli, Alessandro
Classificazione: 1 Contributo su Rivista
Abstract: The paper presents a performance-based approach for the design of flexible breasting dolphins equipped with marine fenders, often used in jetties belonging to offshore oil terminals. Since the distance of the breasting system to the mooring one and to the oil terminal is generally limited for serviceable and operational issues, the proposed design methodology, based on the kinetic energy approach, assumes a predetermined displacement for the dolphin, as well as a desired performance of the fender, and allows evaluating the stiffness of the flexible system required to achieve the desired energy absorption capacity. The design procedure accounts for the dolphin-fender interaction, as well as for the soil-embedded dolphin interaction, and it is specialised considering the common technical solutions adopted in the design of breasting dolphins. The approach is applied to a hypothetical case study consisting of a new berthing structure for a coastal terminal located on the Middle Adriatic Sea, in Italy, presenting non-ideal conditions for the installation of flexible dolphins. Applications demonstrate the effectiveness of the proposed approach and the role of the dolphin-fender interaction in withstanding the berthing actions, making it possible to design a flexible berthing structure also in the case of relatively shallow water depths.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/261976

An integrated permanent dynamic monitoring system of a tall building in central Italy
8th IOMAC - International Operational Modal Analysis Conference, Proceedings
Autore/i: Arezzo, Davide; Regni, Marco; Carbonari, Sandro; Gara, Fabrizio
Editore: International Operational Modal Analysis Conference (IOMAC)
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This paper presents results of the dynamic monitoring of a 10-storey r.c. tower in central Italy, focusing on the effects of ambient conditions. The installed monitoring system consists of a set of three accelerometers located on the last floor of the tower, including a velocimeter located at the foundation level and an acquisition software that, through a specifically developed algorithm based on operational modal analysis techniques, automatically extracts the modal parameters of the building from the accelerometric recordings. Ambient registrations derive from a weather station installed on the roof of the tower. Effects of the ambient parameters on the dynamic properties of the building are presented and discussed. Moreover, the building response to low intensity seismic events registered during the monitoring period is compared with that obtained from a calibrated numerical model by applying at the base the input registered by the velocimeter.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267568

Evaluation of dynamic soil-pile interaction based on both full scale in situ tests and numerical simulations
Earthquake Geotechnical Engineering for Protection and Development of Environment and Constructions
Autore/i: Dezi, Francesca; Roia, Davide; Chiara Capatti, Maria; Carbonari, Sandro; Gara, Fabrizio; Leoni, Graziano; Morici, Michele
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This paper presents some comparisons between results obtained by full-scale experimental dynamic tests and numerical simulations for the evaluation of the dynamic behaviour of soil-pile foundation systems. Two experimental campaigns were considered for this scope: one conducted on vibro-driven steel pipe piles in nearshore environment and the other on vertical injected and not injected micropiles in an alluvial silty deposit. Experimental cam-paigns include ambient vibration and impact tests, as well as snap back and forced vibra-tion tests. A numerical procedure, developed to study the kinematic and inertial interaction of pile foundations in horizontally layered soil profiles, was applied to predict the re-sponse of the 3 types of piles realized in different soil deposits. The primary objective of the comparisons was to assess the accuracy of the numerical procedure in predicting the dynamic response of the pile-foundation system varying the pile construction method and soil nature surrounding the pile shaft.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267572

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

Effects of uncertainties of soil and pile mechanical properties on the dynamic stiffness of deep foundations in homogenous deposits
Eccomas Proceedia COMPDYN (2019) 4157-4165
Autore/i: Minnucci, Lucia; Dezi, Francesca; Carbonari, Sandro; Morici, Michele; Gara, Fabrizio; Leoni, Graziano
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In the soil-structure interaction framework, among the results of the soil-foundation system analysis (kinematic analysis) the dynamic impedance functions represent the force-displacement relationships of the compliant restraint for the superstructure. The intrinsic varia-bility of soil parameters and of design materials represents an uncertainty source which is nec-essary to include in the definition of the soil-foundation model, in order to predict the super-structure response adequately. The aim of this work is to evaluate effects of uncertainties on soil dynamic and mechanical properties on the impedance matrix of single piles in homogeneous soils, focusing on the sensitivity of the parameters. A Quasi Monte Carlo (QMC) simulation with sampling based on Sobol’ sequence is performed starting from the probabilistic distribu-tion of three main parameters characterizing the soil-piles response, i.e. the soil density, the shear waves velocity and the concrete elastic modulus of piles, available from the literature. The analyses are carried out through the numerical model developed by the Authors and a sen-sitivity study on the optimal number of simulations is performed, comparing the use of Quasi-random sampling with the classical Monte Carlo simulation technique. Moreover, results of sensitivity studies show the influence of variability of each considered mechanical parameter on the global response of the soil-foundation system.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267575

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

First analysis of data concerning damage occurred to churches of the marche region following the 2016 central Italy earthquakes
BOLLETTINO DI GEOFISICA TEORICA E APPLICATA
Autore/i: Carbonari, S.; Dall'Asta, A.; Dezi, L.; Gara, F.; Leoni, G.; Morici, M.; Prota, A.; Zona, A.
Classificazione: 1 Contributo su Rivista
Abstract: The seismic sequence that struck central Italy from August to October 2016 caused severe damage to many historical and artistic buildings. In particular, churches were widely affected due to the intrinsic peculiarities of their structural system, unable to develop an efficient box-like resisting mechanism. After the seismic events, teams of experts carried out a massive survey of churches to assess both the occurred damage and their usability. Teams were coordinated by the Department of Civil Protection and the Ministry of Cultural Heritage. In this paper, a methodology for processing the data recorded during the inspections of a number of churches of the Marche region is proposed and used to analyse a sample data set. Starting from the subdivision of the sampled churches into homogeneous typologies, the most recurring damage mechanisms are identified. In addition, the global damage index of each church is correlated with the relevant highest pseudo spectral acceleration at period 0.30 s registered at the site as a consequence of the main shocks; relationships between the seismic intensity and the observed damage are then derived from such a correlation. Finally, the overall damage occurred to churches of the sample is compared to that estimated through empirical models available in the literature.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269326

The Role of Soil-Structure Interaction in the Interpretation of Dynamic Tests on the “Chiaravalle viaduct”
Eccomas Proceedia COMPDYN (2019)
Autore/i: Carbonari, Sandro; Dezi, Francesca; Gara, Fabrizio
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The paper addresses the significance of soil-structure interaction on the dynamic behaviour of the “Chiaravalle viaduct”, based on ambient vibration measurements and numerical simula-tions. The viaduct is located in Central Italy and is founded on piles in an eluvial-colluvial soil deposit. Experimental modal properties are evaluated by means of the operational modal anal-ysis on accelerometric data from ambient excitation and the role of soil-structure interaction in the interpretation of tests is investigated by means of a refined finite element model of the via-duct. In the soil-structure interaction models the local site condition in correspondence of each bridge piers (resulting from geotechnical and geophysical investigations) are considered in the definition of the soil-foundations compliance. Comparison between the experimental and nu-merical results highlight the role of the pile-soil-pile interaction, the radiation problem, the pile cap embedment and the variability of the soil stratigraphy along the longitudinal direction of the viaduct in the interpretation of the experimental data.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267577

Experimental assessment of the expected impact of a bridge seismic retrofit through ambient vibration tests
8th IOMAC - International Operational Modal Analysis Conference, Proceedings
Autore/i: Minnucci, Lucia; Regni, Marco; Speranza, Elisa; Carbonari, Sandro; Gara, Fabrizio
Editore: International Operational Modal Analysis Conference (IOMAC)
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This paper presents and discusses results of ambient vibration tests performed on the Moscosi Bridge in Cingoli (Italy) before and after the execution of seismic retrofitting works. The aim of the first tests is to evaluate the dynamic parameters of the bridge, such as the eigenfrequencies, the mode shapes and the relevant modal damping ratios, in order to build up a numerical model and, through it, to predict the behaviour of the bridge after the interventions. The dynamic characterization of the bridge is obtained through the measurements of ambient vibrations, which are processed with the Covariance-driven Stochastic Subspace Identification. The information derived by the calibrated model are compared with the results of a second ambient vibrational measurement campaign, and the effectiveness of the retrofit is assessed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267570

A practical procedure for time-domain soil-structure interaction analysis of structures on pile foundations
Earthquake Geotechnical Engineering for Protection and Development of Environment and Constructions
Autore/i: Carbonari, Sandro; Minnucci, Lucia; Dezi, Francesca; Morici, Michele; Leoni, Graziano
Editore: CRC Press Taylor & Francis Group
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The paper presents a simplified procedure for the time domain soil-structure interaction analysis of piled structures, based on the use of a lumped parameter model for the approx-imation of the frequency-dependent dynamic stiffness of foundations. The lumped model can be implemented in commercial software to perform linear or nonlinear dynamic anal-yses of structures founded on piles taking into account the frequency dependent coupled roto-translational, vertical and torsional behaviour of the soil-foundation system. Closed-form formulas, calibrated with a nonlinear least square procedure based on data provided by an extensive non-dimensional parametric analysis, are used for estimating parameters of the lumped system. Formulas, which allow defining lumped models representative of pile groups with square layout and different number of piles embedded in soft and stiff soils, can be straightforwardly implemented to perform inertial structural analyses ac-counting for the dynamic behaviour of the soil-foundation system. Some applications on typical bridge piers are presented to show a practical use of the proposed procedure. Re-sults demonstrate the capability of the approach in capturing the actual dynamic response evaluated through a rigorous soil-structure interaction analysis.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267571

Evidence of coupled soil-structure interaction and site response in continuous viaducts from ambient vibration tests
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
Autore/i: Gara, Fabrizio; Regni, Marco; Roia, Davide; Carbonari, Sandro; Dezi, Francesca
Classificazione: 1 Contributo su Rivista
Abstract: The scope of this research was to identify the significance of soil-structure interaction and site response on the dynamic behaviour of continuous multispan reinforced concrete viaducts, based on ambient vibration measurements and numerical simulations, using finite element models. For this purpose, an 875 m long bridge, located in Central Italy, founded on piles in eluvial-colluvial soil deposit was instrumented and ambient vibration tests together with geophysical investigations were performed. Experimental modal properties were evaluated by means of the operational modal analysis on accelerometric data and the role of soil-structure interaction in the interpretation of tests was detected by means of finite element models characterised by different accuracy in addressing the interaction problem. In the soil-structure interaction models the local site condition in correspondence of each bridge piers (resulting from geotechnical and geophysical investigations) were taken into account in the definition of the soil-foundation impedances. Comparison between the experimental results obtained from ambient noise measurements on the free-field and on the bridge deck permits the identification of both the predominant period of the site and the fundamental periods of the structure. In addition, comparisons between results obtained from the different numerical models with the measured dynamic response of the viaduct, in terms of fundamental frequencies and mode shapes, allow the identification of the contribution of different soil-structure interaction aspects such as the pile-soil-pile interaction, the radiation problem, the pile cap embedment as well as the variability of the soil stratigraphy along the longitudinal direction of the viaduct.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/264148

Simple formulas for estimating a lumped parameter model to reproduce impedances of end-bearing pile foundations
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
Autore/i: Morici, Michele; Minnucci, Lucia; Carbonari, Sandro; Dezi, Francesca; Leoni, Graziano
Classificazione: 1 Contributo su Rivista
Abstract: The paper presents simple formulas to evaluate parameters of a lumped system reproducing the frequency-dependent dynamic stiffness of end-bearing pile foundations. The model can be implemented in commercial finite element software and allows performing inertial soil-structure interaction analyses of structures considering the coupled roto-translational, vertical and torsional behaviour of the soil-foundation system. Pile groups arranged in a square layout are considered; the soil profile is constituted by a homogeneous deformable soil layer overlying a bedrock where piles are socked for a fixed length. Formulas are calibrated with a nonlinear least square procedure, based on data provided by an extensive non-dimensional parametric analysis of the soil-foundation systems, performed with a Winkler's type model, previously developed by the authors, which assumes soil and piles to behave linearly. Firstly, the suitability of the adopted numerical tools in capturing the dynamic stiffness of end-bearing foundations is proven. Then, capabilities of the proposed formulas in estimating parameters of the best lumped systems are shown, and, for some case studies, comparisons of non-null terms of the impedance matrix obtained through the best lumped system, the one computed through the formulas, and the impedances resulting from the dynamic analyses, are presented. Finally, some applications of the proposed formulas in the framework of the seismic soil-structure interaction analysis of bridges are shown to demonstrate the capability of the adopted lumped system and the formula efficiency in assuring a reliable evaluation of the superstructure seismic response, with respect to that obtained from a more rigorous approach.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/264706

Dynamic Test Based Model Calibration of an Existing R.C. School Building
The 2018 World Congress on Advances in Civil, Environmental and Materials Research (ACEM18) & The 2018 Structures Congress (Structures18)
Autore/i: Speranza, E.; Gara, F.; Carbonari, S.; Balducci, A.; Dezi, L.
Editore: Chang-Koon Choi
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This paper deals with the dynamic tests carried out on a school building seismically retrofitted with an innovative system that uses external steel dissipative towers. Before the retrofitting, ambient vibration tests were carried out with the aim of evaluating the modal parameters of the building including the contribution of nonstructural components to the global dynamic behavior of the structure. In particular, the contribution of non-structural components plays fundamental role in structural design because neglecting the infills in finite element models can produce macroscopic errors that may compromise the capacity of the models to predict the structural response of the structure when used for design purposes, such as for seismic retrofitting projects. In this context, the calibration of the finite element models (f.e. models) through experimental measurements plays a fundamental role in ensuring that the models reproduce with sufficient reliability the real behavior of the structure. After the building retrofitting, ambient vibration measurements were repeated to verify that variations in modal properties of the building, evaluated at very small input energy level, are in accordance with those expected from the numerical model. Furthermore, snap-back tests of the building were performed at different load levels to assess the dissipative capacity of the new structural system at greater input energy level.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259688

Artificial neural networks for the evaluation of impedance functions of inclined pile groups
Numerical Methods in Geotechnical Engineering IX: Proceedings of the 9th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE 2018)
Autore/i: Franza, A.; Dejong, M. J.; Morici, M.; Carbonari, S.; Dezi, F.
Editore: CRC Press
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Recent works provided insights into the role of inclined piles on the dynamic response of structures. However, there is a lack of design tools that can be implemented to perform inertial soil-structure interaction analyses, in the framework of the sub-structure approach, bypassing the numerical modelling of the kinematic interaction problem. For this purpose, this paper presents the application of ANNs to the impedance functions of inclined pile groups. Firstly, the dataset required for the training and testing of the ANNs is obtained from a parametric investigation in which the frequency-dependent impedance functions of 2x2 pile groups rigidly connected at the head and embedded in homogeneous soil deposits are considered. A dimensional analysis of the problem is performed and soil-foundation systems with different geometric characteristic and properties (e.g. inclination angles, pile-soil stiffness ratios, pile length-to-diameter ratios) are investigated. Data, representing the target of the neural networks, are obtained through a numerical FE model developed by the authors. The main trends of impedances with the dimensionless parameters of the pile groups are inferred from the presented results. Subsequently, several ANNs consisting of two hidden layers are trained, tested, and validated to optimise the generalisation performance of the model. Results show that ANNs are able to capture the trends of the impedance functions of inclined pile groups on the basis of the adopted dimensionless parameters. In addition, the complexity of the ANN models achieving good performance confirms the need for advanced regression models.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259403

Dynamic Test for the Model Calibration and Pier Damage Detection of an Existing R.C. Multispan Viaduct
The 2018 World Congress on Advances in Civil, Environmental and Materials Research (ACEM18) & The 2018 Structures Congress (Structures18)
Autore/i: Gara, F.; Carbonari, S.; Minnucci, L.; Regni, M.; Speranza, E.
Editore: Chan-Koon Choi
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This paper presents and discusses results of the dynamic tests performed on the Moscosi Bridge in Cingoli (Italy). The main scope of the tests is to evaluate the dynamic parameters of the bridge, such as the eigenfrequencies, the mode shapes and the relevant modal damping ratios, in order to characterize the structural behaviour before the execution of some required restoration works, providing (i) useful information for the development of the numerical model for the design and (ii) a benchmark for the evaluation of the retrofit effectiveness, by repeating tests after the retrofit. The dynamic characterization is obtained through the measurements of ambient vibrations, which are processed with the Covariance-driven Stochastic Subspace Identification. In addition, the dynamic response of the bridge subjected to a vehicle passages is registered and compared to that induced by the ambient excitations. First considerations seem to reveal the presence of the observed structural damage at the base of one pier.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259689

Seismic behaviour of steel-concrete composite bridge decks
Steel and Steel-concrete composite structures in seismic areas: advances in research and design. The Research Project RP3 of the ReLUIS-DPC 2014-2018 – Activity carried out during years 2014-2016
Autore/i: Dezi, L.; Carbonari, S.; Dall’Asta, A.; Gara, F.; Minnucci, Lucia
Editore: Doppiavoce
Luogo di pubblicazione: Napoli
Classificazione: 2 Contributo in Volume
Abstract: The paper focuses on local problems relevant to the seismic response of steel-concrete composite bridge decks. In particular, the local mechanisms involved in the transferring of inertial forces from the slab to substructures are investigated with particular focus on the shear connection and the role of end cross beams. Firstly, open issues relevant to the seismic design and analysis of steel-concrete composite bridge decks are discussed and an overall state-of-art of the problem is depicted. Then, some case studies constituted by single span and two-spans I-shaped twin-girders and box girders steel-concrete composite bridges are selected and adopted to investigate local response of the decks subjected to seismic actions. Linear and non-linear applications are performed adopting different analysis methodologies in order to investigate stress resultants in the shear connection and to analyse the role of the end cross beams on the local transferring mechanisms of inertia forces; results of analyses on the selected case studies are shown and discussed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259405

First processing and remarks on the observed damage to the churches of the Marche Region after the centre Italy earthquake 2016
Proceedings of the 8th International Conference on Building Resilience – ICBR Lisbon’2018 Risk and Resilience in Practice: Vulnerabilities, Displaced People, Local Communities and Heritages
Autore/i: Carbonari, Sandro; Dall’Asta, Andrea; Dezi, Luigino; Gara, Fabrizio; Leoni, Graziano; Morici, Michele; Prota, Andrea; Zona, Alessandro
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The seismic sequence that struck Central Italy in August-October 2016 seriously damaged many historical buildings of the Italian cultural heritage. In particular, churches were widely damaged due to intrinsic peculiarities of their structural systems, not able to develop an efficient box-like resisting mechanism. During seismic emergency, teams of experts carried out a massive survey of churches to assess both the occurred damage and their usability. Teams have been coordinated by the Department of Civil Protection and the Ministry of Cultural Heritage and Tourism. In this paper, a methodology for processing data recorded during inspections of churches of the Marche Region is proposed and used to analyse a limited dataset. Starting from the subdivision of the sample into homogeneous typologies, the most recurring damage mechanisms are identified. In addition, the global damage indexes of each churches are correlated with the relevant highest spectral pseudo acceleration at T=0.30s registered at the site as a consequence of the main shocks; this allows obtaining relationships between the seismic intensity and the expected damage. Finally, the overall damage occurred to churches of the sample is compared to that estimated through empirical models available in the literature.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/263175

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

A Lumped Parameter Model for Time-Domain Inertial Soil-Structure Interaction Analysis of Structures on Pile Foundations
EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS
Autore/i: Carbonari, S.; Morici, M.; Dezi, F.; Leoni, G.
Classificazione: 1 Contributo su Rivista
Abstract: The paper presents a lumped parameter model for the approximation of the frequency-dependent dynamic stiffness of pile group foundations. The model can be implemented in commercial software to perform linear or nonlinear dynamic analyses of structures founded on piles taking into account the frequency dependent coupled roto-translational, vertical and torsional behaviour of the soil-foundation system. Closed-form formulas for estimating parameters of the model are proposed with reference to pile groups embedded in homogeneous soil deposits. These are calibrated with a nonlinear least square procedure, based on data provided by an extensive non-dimensional parametric analysis performed with a model previously developed by the authors. Pile groups with square layout and different number of piles embedded in soft and stiff soils are considered. Formulas are overall well capable to reproduce parameters of the proposed lumped system that can be straightforwardly incorporated into inertial structural analyses to account for the dynamic behaviour of the soil-foundation system. Some applications on typical bridge piers are finally presented to show examples of practical use of the proposed model. Results demonstrate the capability of the proposed lumped system as well as the formulas efficiency in approximating impedances of pile groups and the relevant effect on the response of the superstructure.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259406

Soil-foundation compliance evidence of the “Chiaravalle viaduct”
Lecture Notes in Civil Engineering, 2018
Autore/i: Regni, Marco; Gara, Fabrizio; Francesca, Dezi; Davide, Roia; Carbonari, Sandro
Editore: Springer
Classificazione: 2 Contributo in Volume
Abstract: This paper describes some notable aspects demonstrating the contribution of the soil-foundation compliance on the measured dynamic response of the Chiaravalle viaduct subjected to ambient excitations. The viaduct, linking the SS76 with the airport of Ancona (in Central Italy), is 875 m long and consists of four r.c. kinematic chains separated by joints. The deck is constituted by three beams supported by column bent piers constituted by two circular r.c. columns founded on a continuous footing on six concrete piles. Ambient vibration measurements have been performed to determine experimental natural frequencies and mode shapes of the viaduct before a scheduled seismic rehabilitation of the structure; data have been used to calibrate a numerical model for the retrofit design. Experimental modal properties are evaluated by means of Operational Modal Analysis; due to the great length of the viaduct, different configurations of sensors placed on the deck are used to evaluate the overall behavior of the viaduct and the Pre Global Estimation Re-scaling method is adopted in order to merge the different parts of mode shapes relevant to each configuration. Furthermore, with reference to the transverse behaviour, some tests are performed in correspondence of one pier, measuring accelerations of the foundation cap (both translational and rotational components) and the pier bent, in order to identify contribution to the transverse modal displacement due to the elastic deflection of the pier and the foundation rocking. Results of dynamic tests are interpreted through a 3D Finite Element model of the viaduct. Firstly, a conventional fixed base model is considered, then a model including the Soil-Structure Interaction problem is developed in order to improve consistency between numerical and experimental results. The numerical model including Soil-Structure Interaction is able to capture the foundation rocking, experimentally detected, and provides modal parameters in good agreement with the experimental ones.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251324

Shear connection local problems in the seismic design of steel-concrete composite decks
Lecture Notes in Civil Engineering
Autore/i: Carbonari, Sandro; Gara, Fabrizio; Dall’Asta, A.; Dezi, Luigino
Editore: Springer, Cham
Classificazione: 2 Contributo in Volume
Abstract: This paper investigates local problems involved in the transfer mechanisms of inertia forces acting at the level of the concrete slab of typical steel-concrete composite bridge decks. In detail, the behaviour of the shear connection, usually designed with only refer-ence to non-seismic loads at the ultimate limit state, is studied considering shear forces descending from both horizontal and trans-verse seismic actions. Some results concerning twin-girder steel-concrete composite bridge decks characterised by different static schemes are presented and the distribution of longitudinal and transverse forces acting on the shear connection is discussed. First results demonstrate the significance of properly considering seismic induced forces in the design of the steel-concrete shear connec-tion and support the need of further investigations.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/240818

Full scale experimental assessment of the dynamic horizontal behavior of micropiles in alluvial silty soils
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
Autore/i: Capatti, M. C.; Dezi, F.; Carbonari, S.; Gara, F.
Classificazione: 1 Contributo su Rivista
Abstract: The paper deals with an extensive experimental campaign of dynamic tests performed on full-scale vertical injected and not injected micropiles embedded in alluvial soils. The experimentation includes ambient vibration and impact load tests to investigate the dynamic behaviour of the soil-micropile system in very small and small-medium strain ranges, as well as snap back tests to investigate the evolution of the post-elastic response of the system. Micropiles are instrumented with strain gauges along the shaft, accelerometers and displacement transducers at the head. Modalities and results of the different performed tests are presented, focusing on the role of high pressure injections on the dynamic behaviour of the system, on the development of non-linear soil-pile phenomena, and, finally, on the evaluation of effectiveness of the different testing procedures to capture the dynamic response of soil-micropile systems. Ambient vibration test revealed to be a versatile method to identify the dynamic properties of soil-micropile systems, although it requires demanding post-processing techniques of data. Impact load test is faster to perform and easier to post process. Free vibration test proved to be relatively simple to perform and able to catch the dynamic non-linear behaviour of soil-micropile systems.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/258773

Effect of Environmental Conditions on the Modal Response of a 10-Story Reinforced Concrete Tower
SHOCK AND VIBRATION
Autore/i: Regni, Marco; Arezzo, Davide; Carbonari, S.; Gara, F.; Zonta, D.
Classificazione: 1 Contributo su Rivista
Abstract: We analyse the effect of temperature and wind velocity on the natural frequencies and modal damping ratios of the Faculty of Engineering Tower at the Universit`a Politecnica delle Marche, a 10-story reinforced concrete frame building, permanently monitored with low-noise accelerometers. The data recorded over the first 5 months of monitoring demonstrate that temperature variations and wind intensity have a clear effect on the first three natural frequencies and the corresponding damping ratios. Temperature is positively correlated to the first and second frequencies, corresponding to shear displacement modes and negatively correlated to the third frequency, corresponding to a torsional mode. All frequencies are positively correlated to wind velocity and changes in damping ratios are inversely correlated to any change in frequency. A mechanical explanation of these phenomena is offered, based on a critical review of literature case studies. These results suggest that using changes in modal parameters for damage detection always requires accurate knowledge of the correlation between modal parameters and environmental quantities (temperature, humidity, and wind velocity), an information which is only available through long-term continuous monitoring of the structural response.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259024

A low cost wireless sensor node for building monitoring
EESMS 2018 - Environmental, Energy, and Structural Monitoring Systems, Proceedings
Autore/i: Valenti, S.; Conti, M.; Pierleoni, P.; Zappelli, L.; Belli, A.; Gara, F.; Carbonari, S.; Regni, M.
Editore: Institute of Electrical and Electronics Engineers Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259400

Effects of environmental conditions on the dynamic properties of a 10-storey r.c. square tower
EESMS 2018 - Environmental, Energy, and Structural Monitoring Systems, Proceedings
Autore/i: Arezzo, Davide; Regni, Marco; Carbonari, Sandro; Gara, Fabrizio
Editore: Institute of Electrical and Electronics Engineers Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259402

Prime Rielaborazioni Circa i Danni Rilevati alle Chiese delle Marche a Seguito del Terremoto del Centro Italia (2016)
Gruppo Nazionale di Geofisica della Terra Solida - 36° convegno nazionale - Trieste, 14-16 novembre 2017
Autore/i: Carbonari, S.; Dall’Asta, A.; Dezi, L.; Gara, F.; Leoni, G.; Morici, M.; Prota, A.; Zona, A.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Le chiese sono edifici con valore storico e artistico che presentano una diffusione capillare nel territorio dell’Italia centrale e costituiscono una componente importante del patrimonio culturale. Il corpo di fabbrica di una chiesa è costituito da sottosistemi strutturali ricorrenti quali la facciata, le pareti laterali, il transetto, l’abside, la navata centrale e laterali, che tendono ad esibire risposte sismiche spesso indipendenti Studi effettuati sui danni subiti dalle chiese a seguito degli eventi sismici del Friuli 1976 (Doglioni et al. 1994), di Umbria-Marche 1997 (Lagomarsino e Podestà 2004a,b), del Molise 2002 (Lagomarsino e Podestà 2004c) dell’Aquila 2009 (Lagomarsino 2012) e dell’Emilia 2012 (Indirli et al. 2012, Sorrentino et al. 2014) hanno mostrato come i meccanismi di danno presentino caratteristiche ricorrenti nonostante l’unicità di ogni corpo di fabbrica. Partendo dalle conoscenze maturate nei precedenti studi eseguiti a seguito di eventi sismici importanti, in questo lavoro gli autori hanno rielaborato i primi dati relativi al danneggiamento subito dal patrimonio culturale marchigiano con l’obiettivo finale di individuare le relazioni che intercorrono tra danno osservato e intensità di scuotimento..Lo studio, di carattere metodologico, prende in esame un sottoinsieme dei dai dati raccolti nella visita di circa 3600 chiese e intende principalmente mettere in evidenza i problemi connessi all'elaborazione di informazioni spesso non omogenee, proponendo alcune strategie per la loro interpretazione.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/258369

An innovative seismic protection system for existing buildings: external dissipative towers
Proceedings of the 16th World Conf. on Earthquake Engineering, WCEE 2017
Autore/i: Gioiella, Laura; Balducci, A.; Carbonari, Sandro; Gara, Fabrizio; Dezi, Luigino
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: A common technique for the retrofit of existing structure is based on the installation of dissipative devices connecting adjacent storeys of buildings in either diagonal or chevron brace configurations. This type of damping system may present some disadvantages like the increment of axial forces in columns, which may leads to premature local failures, or some feasibility limits on the strengthening of the existing foundations at the base of the bracing system. In addition, indirect costs related to the interruption of the building utilization during execution of the retrofit can be very demanding, in particular for strategic buildings, such as hospitals or schools. Most of previous problems can be overcome by placing the dissipative bracings and the relevant foundations outside the building; systems with external dampers can be grouped into three main categories, depending on the kinematic behaviour of the system, which is a function of the arrangement of dampers and bracings. Recently, some applications have been developed by proposing a new configuration exploiting the rocking motion of a stiff external tower. This paper deals with this innovative system for seismic protection of existing buildings, especially strategic ones, patented as “Dissipative Towers”. The protection system is based on the structural coupling of the building with new steel truss towers constructed externally and then rigidly connected to the building floors by means of steel elements; the towers are erected over a rigid r.c. thick base plate that is restrained to the foundation cap with a spherical hinge located in central position of the base slab. The towers are equipped with dissipative devices connecting the corners of the two plates; the effectiveness of the dampers is enhanced by the use of articulated quadrangles which amplify the vertical displacements of the devices. The efficiency of the system is so high that usually it is designed to satisfy the immediate occupancy limit state even for high intensity earthquakes. The above system is applied to the retrofit of an existing school building in Italy, constituted by different blocks made of reinforced concrete frames. The seismic rehabilitation is obtained by suitably positioning external dissipative towers and eliminating expansion joints between adjacent blocks. The towers allow a high level of seismic protection at the ultimate limit state, with a significant reduction of horizontal displacements and accelerations. Moreover also the shear actions resisted by the existing frame are significantly reduced by the "Dissipative Towers". The seismic protection is achieved with a moderate economic impact due to the elimination of indirect costs related to the arrangement of internal spaces, interruption and/or relocation of activities.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/247090

Risposta sismica non lineare di pile da ponte fondate su gruppi di pali inclinati
Atti del 17° Convegno Nazionale – L’ingegneria sismica in Italia (ANIDIS 2017)
Autore/i: Michele, Morici; Carbonari, Sandro; Gara, Fabrizio; Francesca, Dezi; Graziano, Leoni
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Questo lavoro presenta i primi risultati di una ricerca orientata allo studio degli effetti della configurazione e dell’inclinazione dei pali sulla risposta sismica non lineare di pile da ponte. La metodologia di analisi, basata su un approccio alle sottostrutture, viene preventivamente presentata; il sistema terreno-fondazione è analizzato nel dominio delle frequenze adottando un modello numerico sviluppato dagli autori mentre l’analisi di interazione inerziale delle sovrastrutture è svolta nel dominio del tempo per coglierne il comportamento non lineare. La dipendenza dalla frequenza delle funzioni di impedenza del sistema terreno-fondazione è approssimata nel dominio del tempo, attraverso un opportuno modello a parametri concentrati. La procedura è applicata ad alcuni casi studio costituiti da pile da ponte singole fondate in depositi di terreno argilloso di modesta ed elevata rigidezza. Sono considerate fondazioni costituite da pali aventi diversa inclinazione e pile caratterizzate da diversi periodi fondamentali e momenti flettenti di snervamento delle sezioni trasversali di base, al fine di simulare sistemi con diverso comportamento elastoplastico. I risultati delle analisi evidenziano il ruolo chiave rivestito dal rocking di fondazione sulla risposta strutturale e dimostrano che le fondazioni con pali inclinati possono contribuire a ridurre gli spostamenti massimi della testa della pila e la domanda di duttilità.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251351

Effetti del non sincronismo del moto sismico indotto da effetti di sito e dalla non linearità del terreno sulla risposta sismica di ponti fondati su pali
Atti del 17° Convegno Nazionale – L’ingegneria sismica in Italia (ANIDIS 2017)
Autore/i: Capatti, MARIA CHIARA; Giuseppe, Tropeano; Michele, Morici; Carbonari, Sandro; Francesca, Dezi; Graziano, Leoni; Francesco, Silvestri
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Questo lavoro intende investigare gli effetti dell’asincronismo del moto sismico indotto da effetti di sito e dal comportamento non lineare del terreno sulla risposta sismica di lunghi viadotti multicampata con fondazioni su pali. In particolare, è stato esaminato un caso studio rappresentato da un viadotto fondato in un deposito di argilla tenera su substrato roccioso rigido, caratterizzato da una morfologia a cuneo. Il moto di riferimento su bedrock affiorante è costituito da un set di accelerogrammi reali e l’analisi di risposta sismica è stata effettuata con diversi metodi di analisi. Nelle analisi si è inoltre tenuto conto dell’interazione terreno-fondazione-struttura, utilizzando il metodo delle sottostrutture: in particolare l’analisi di interazione cinematica è stata formulata nel dominio delle frequenze, e sono poi stati utilizzati appropriati modelli a parametri concentrati per riprodurre il comportamento dipendente dalla frequenza del sistema terreno-fondazione nelle analisi non lineari di interazione inerziale della sovrastruttura. I risultati delle analisi, eseguite considerando sia moto sincrono che asincrono, hanno messo in luce la rilevanza della configurazione del deposito, del comportamento non lineare del terreno e dell’interazione terreno-fondazione-struttura sulla risposta sismica di viadotti fondati su pali.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251348

Prime analisi e considerazioni circa i danni rilevati al patrimonio culturale delle Marche a valle del terremoto del Centroitalia (2016)
Atti del 17° Convegno Nazionale – L’ingegneria sismica in Italia (ANIDIS 2017)
Autore/i: Carbonari, Sandro; Alessandro, Catanzaro; Valerio, D’Agostino; Andrea, Dall’Asta; Dezi, Luigino; Gara, Fabrizio; Graziano, Leoni; Michele, Morici; Andrea, Prota; Alessandro, Zona
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: La sequenza sismica che ha interessato l’Italia centrale a partire dal 24 Agosto 2016 ha provocato danni anche di grave entità a molti edifici di importanza storica e artistica. In particolare, per le peculiarità degli impianti strutturali incapaci di sviluppare un meccanismo resistente scatolare, le chiese sono state la tipologia di edifici storici maggiormente colpita. A seguito dell’emergenza sismica, squadre composte da tecnici esperti hanno eseguito sopralluoghi sulle chiese segnalate con il fine di valutare sia l’entità del danno che lo stato di sicurezza. Le squadre sono state coordinate dal Dipartimento di Protezione Civile (DPC) e dal Ministero dei Beni e delle Attività Culturali e del Turismo (MiBACT), tramite le strutture operanti all'interno della direzione di comando e controllo (Dicomac) e le sedi regionali del MiBACT. Nel presente lavoro, i dati registrati nelle schede A-DC compilate durante i sopralluoghi sono stati rielaborati per un campione di chiese della regione Marche. Operando sul campione si propone una metodologia di analisi che potrà in futuro applicarsi alla totalità dei dati. Partendo dalla suddivisione del campione in tipologie omogenee, sono stati analizzati i meccanismi di danno più ricorrenti. In aggiunta, gli indici di danno globali di ogni chiesa sono stati correlati con i massimi valori di Pseudo Accelerazione Spettrale a 0.30s registrati in sito in conseguenza delle maggiori scosse, nel tentativo di derivare una relazione tra intensità di scuotimento e danno atteso. Infine i danni rilevati nel campione sono stati confrontati con quelli forniti dai modelli empirici di vulnerabilità messi a punto sulla scorta dei dati registrati a seguito del terremoto Umbria-Marche 1997.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251347

Un modello analitico per l’interazione cinematica di pali singoli inclinati
Atti del 17° Convegno Nazionale – L’ingegneria sismica in Italia (ANIDIS 2017)
Autore/i: Carbonari, Sandro; Michele, Morici; Francesca, Dezi; Graziano, Leoni
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Questo lavoro presenta un modello analitico, basato sull’approccio di trave su suolo alla Winkler di tipo dinamico, per la valutazione delle sollecitazioni cinematiche in pali singoli inclinati dovute alla propagazione di onde sismiche nel terreno. I pali sono modellati con elementi trave di Eulero-Bernoulli e l’interazione con il terreno è colta sfruttando soluzioni analitiche disponibili in letteratura relative a strati di materiale viscoelastico soggetti a vibrazioni armoniche di dischi rigidi. Il comportamento accoppiato assiale e flessionale del palo è governato da un sistema di equazioni differenziali alle derivate totali, con le relative condizioni al contorno, che è risolto, con riferimento al caso del palo infisso in un deposito di terreno omogeneo, sfruttando le matrici esponenziali. Alcune applicazioni dimostrano, dal confronto dei risultati con quelli ottenuti da formulazioni rigorose agli elementi di contorno, che il modello proposto, caratterizzato da un basso onere computazionale, è capace di predire in modo accurato le sollecitazioni che si sviluppano in pali inclinati soggetti ad azioni sismiche.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251349

Assessment survey of public school buildings after August 2016 Italy earthquake: preliminary results
Proceedings of the 16th World Conference on Earthquake Engineering (16WCEE)
Autore/i: Abruzzese, D.; Bergami, A.; Biondi, S.; Camata, G.; Canciani, M.; Carbonari, Sandro; Cimino, A.; Dall’Asta, A.; Dezi, F.; Dezi, Luigino; Di Fabio, F.; Ferracuti, B.; Fiorentino, G.; Forte, A.; Fragiacomo, M.; Gara, Fabrizio; Ianniruberto, U.; Imperatore, S.; Lavorato, D.; Leoni, G.; Liberatore, D.; Liberatore, L.; Mannella, A.; Martinelli, A.; Mutignani, C.; Nuti, C.; Paolacci, F.; Pagano, E.; Rasulo, A.; Santini, S.; Sorrentino, L.; Vanzi, I.; Zucconi, M.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/247082

Lumped Parameter Models for Time Domain Soil-Structure Interaction Analysis: Consistent vs Simplified Formulations and Effects on the Linear and Nonlinear Superstructure Response
Proceedings of DISS_17 5th International Workshop on dynamic interaction of soil and structure
Autore/i: González, Francisco; Morici, Michele; Carbonari, Sandro; Dezi, Francesca; Chiara Capatti, Maria; Leoni, Graziano; Padrón, Luis A.; Aznárez, Juan J.; Maeso, Orlando
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Due to the frequency-dependency of soil-foundation impedances, the dynamic interaction analysis of linear and nonlinear systems in time domain according to the sub-structure approach requires the defi-nition of suitable Lumped Parameter Models (LPMs) with frequency independent parameters to simulate the soil-foundation compliance. This paper investigates effects on the superstructure response resulting from the use of different LPMs. In particular, consistent and simpli-fied LPMs are considered and the linear response of single bridge piers founded on different pile foundations is studied. The effectiveness of selected LPMs is evaluated using results obtained from a direct ap-proach in the frequency domain as benchmark. Results demonstrate that simplified models can be sufficient in most cases to obtain a relia-ble prediction of the superstructure response.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/258370

Validazione di un modello 3D per l’interazione dinamica terreno-struttura mediante prove in sito su fondazioni profonde
Atti del 17° Convegno Nazionale – L’ingegneria sismica in Italia (ANIDIS 2017)
Autore/i: Capatti, MARIA CHIARA; Carbonari, Sandro; Francesca, Dezi; Gara, Fabrizio; Graziano, Leoni; Michele, Morici
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In questo articolo viene presentata e discussa la duplice validazione di un modello numerico per l’interazione dinamica terreno-fondazione-struttura nel caso di fondazioni profonde. Il modello, originariamente sviluppato per gruppi di pali verticali in terreni stratificati, e recentemente aggiornato per tener conto dell’inclinazione dei pali, considera l’interazione terreno-palificata e lo smorzamento per radiazione attraverso funzioni elastodinamiche di Green. La validazione è basata su dati sperimentali ottenuti attraverso due distinte campagne sperimentali. La prima campagna prove riguarda tre pali in acciaio vibro-infissi in ambiente marino, sui quali sono state eseguite prove di impatto e prove di snap-back, misurando le deformazioni lungo il palo sorgente e le accelerazioni in testa al palo sorgente e a quelli riceventi. Il secondo gruppo di dati sperimentali è stato ottenuto durante una recente campagna prove su due micropali singoli verticali e su un gruppo di tre micropali inclinati in terreno limoso alluvionale, durante la quale sono state eseguite prove di vibrazioni ambientali e di impatto, prove di snap-back e prove in condizioni di vibrazioni forzate. Attraverso il confronto tra dati numerici e sperimentali in termini di impedenza del sistema, si discute la capacità previsionale del modello nel simulare il fenomeno dell’interazione palo terreno al variare della tipologia di fondazione profonda.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251352

The Role of End Cross-beams on the Distribution of Seismic Induced Shear Actions on the Shear Connection in Steel-Concrete Composite Bridge Decks
Atti delle XXVI Giornate Italiane della Costruzione in Acciaio
Autore/i: Carbonari, Sandro; Minnucci, Lucia; Gara, Fabrizio; Dezi, Luigino; Andrea, Dall'Asta
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This paper focuses on local problems arising in the shear connection of typical steel-concrete com-posite bridge decks subjected to seismic actions. In detail, a case study constituted by an I-shaped twin-girder simply supported steel concrete composite deck is considered and the distribution of forces on the shear connection along the beams is presented, focusing on the role of end cross-beams. After a brief survey of the results obtained in previous researches by the authors, aimed at justifying the adopted analysis methodology, results of static equivalent seismic analyses of the se-lected case studies are shown and discussed, considering end cross-beams of different typology and stiffness. Results demonstrate the key role played by end cross-beams on the distribution of seismic actions on the shear connection.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251353

Implications of non-synchronous excitation induced by nonlinear site amplification and of soil-structure interaction on the seismic response of multi-span bridges founded on piles
BULLETIN OF EARTHQUAKE ENGINEERING
Autore/i: Capatti, MARIA CHIARA; Tropeano, Giuseppe; Morici, Michele; Carbonari, Sandro; Dezi, Francesca; Leoni, Graziano; Silvestri, Francesco
Classificazione: 1 Contributo su Rivista
Abstract: This work investigates the effects of soil-structure interaction and spatial variability of seismic motion due to nonlinear site amplification on the seismic behaviour of long multi-span bridges founded on piles. An analysis framework able to include the spatial variation of ground motion induced by specific geological and geomorphological scenarios in the seismic soil-structure interaction analysis of long bridges is adopted, exploiting advantages of the substructure approach. The methodology is applied to a case study constituted by a pile-supported multi-span bridge founded in a soft clay deposit overlaying a stiff bedrock with three different configurations: horizontal, inclined and wedge-shaped. The reference input motion at the outcropping bedrock is represented by a set of real accelerograms and different seismic response models are used to compute site amplification effects, discussing the contribution to the free-field ground motion of both the two-dimensional configuration of the deposit and the nonlinear soil behaviour. The ground motions obtained from the different models are then used for computing the foundation input motion accounting for the pile-soil kinematic interaction; thereafter, inertial interaction analyses are performed on structural models with either fixed or compliant base, considering the non-synchronous seismic actions at the piers foundation. The results, compared in terms of piers head displacements, ductility demand and deck transverse bending moments, finally show the relative importance of bedrock morphology, soil nonlinearity and soil-structure interaction on the structural response.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251320

Erratum to: Implications of non-synchronous excitation induced by nonlinear site amplification and of soil-structure interaction on the seismic response of multi-span bridges founded on piles
BULLETIN OF EARTHQUAKE ENGINEERING
Autore/i: Capatti, MARIA CHIARA; Tropeano, Giuseppe; Morici, Michele; Carbonari, Sandro; Dezi, Francesca; Leoni, Graziano; Silvestri, Francesco
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251321

Kinematic Stress Resultants in Inclined Single Piles Subjected to Propagating Seismic Waves: an Analytical Formulation
Computational Methods in Structural Dynamics and Earthquake Engineering
Autore/i: Carbonari, Sandro; Morici, M.; Dezi, F.; Leoni, G.
Editore: M. Papadrakakis, M. Fragiadakis eds.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This paper presents an analytical model, based on the beam-on-dynamic Winkler foundation approach, for the evaluation of the kinematic stress resultants in single inclined piles subjected to the propagation of seismic waves. The Euler-Bernoulli beam model is adopted for the pile whereas analytical solutions available in literature for viscoelastic layers undergoing harmonic vibrations of a rigid disk are used for the soil. The coupled flexural and axial behaviour of the pile is governed by a system of partial differential equations, with the relevant boundary condi-tions, that is solved analytically in terms of exponential matrices. The solution for piles embed-ded in a homogeneous soil deposit is presented. Some applications, including comparisons of results with those obtained from rigorous boundary element formulations, demonstrate that the model, characterised by a very low computational effort, is able to accurately predict stress re-sultants in inclined piles subjected to seismic loading.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251323

Soil-structure interaction effects in single bridge piers founded on inclined pile groups
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
Autore/i: Carbonari, Sandro; Morici, Michele; Dezi, Francesca; Gara, Fabrizio; Leoni, Graziano
Classificazione: 1 Contributo su Rivista
Abstract: This paper investigates the seismic response of bridge piers founded on inclined pile groups in different soil deposits, evaluating effects of soil-structure interaction induced by different pile group geometries and piles inclinations. Analyses are performed in the frequency domain by means of the direct approach taking advantage of a numerical model developed by the authors for the analysis of inclined pile groups. Both the superstructure and piles are modelled with beam elements and the soil is schematized as a visco-elastic medium constituted by independent infinite horizontal layers. The soil-pile and the pile-soil-pile interaction are captured in the frequency domain by means of elastodynamic Green’s functions that also allow including the hysteretic and radiation damping. The significance of kinematic stress resultants in piles, the foundation filtering effect and the rotational component of the input motion due to the coupled roto-translational behaviour of the soil-foundation system are also investigated; to this purpose kinematic interaction analyses are performed. These analyses revealed essential for the understanding of the general phenomena governing the dynamic response of the whole soil-foundation-superstructure systems. Results of numerical investigations highlight that conventional design approaches suggested by codes do not provide reliable predictions of the superstructure displacements and stress resultants.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/240768

Dynamic behaviour of a retrofitted school building subjected to the after-shock sequence of the 2016 Central Italy earthquake
Procedia Engineering
Autore/i: Gara, Fabrizio; Regni, Marco; Carbonari, Sandro; Balducci, Alessandro; Dezi, Luigino
Editore: Elsevier Ltd
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This paper deals with the dynamic behaviour of a 1960s school building in Camerino subjected to moderate earthquakes belonging to the after-shock sequence of the 2016 Central Italy earthquake. The school structure, constituted by RC frames, was seismically retrofitted by means of "Dissipative Towers", an innovative system based on the use of external stiff steel truss towers equipped with dissipative dampers. Modal properties of the building after the retrofit have been determined through ambient vibration tests. After the main shock of the 2016 Central Italy earthquake, the building was instrumented with low-noise accelerometers and the dynamic behaviour of the structure during several aftershocks was recorded. Firstly, a numerical finite element model of the building is developed and calibrated on the basis of the ambient vibration measurements; then the registered dynamic response of the structure for the highest aftershock event (among the registered ones) is compared with that obtained numerically with the calibrated model. Results demonstrate the good agreement of the registered and predicted response.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251328

A simplified elastic analysis of tunnel-piled structure interaction
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
Autore/i: Franza, Andrea; Marshall, Alec M.; Haji, Twana; Abdelatif, Amged O.; Carbonari, Sandro; Morici, Michele
Classificazione: 1 Contributo su Rivista
Abstract: In urban areas, engineers often need to assess tunnelling-induced displacements of piled structures and the resulting potential for damage. This paper presents an elastic study of tunnel-pile-structure interaction through Winkler-based Two-Stage Analysis Methods (TSAMs), focusing on structural displacements resulting from tunnel excavation beneath piled frames or simple equivalent beams. Comparison of results with 3D finite element analyses shows that the simple TSAM models are able to provide a good assessment of tunnelling-induced building displacements. Parametric analyses highlight the role of tunnel-pile interaction and the superstructure (stiffness, configuration, and pile-structure connections) in the global response of the tunnel-soil-building system. In particular, the effect that key parameters have on deflection ratios and horizontal strains are investigated. Results illustrate how piled foundations increase the risk of structural damage compared to shallow foundations, whereas structural stiffness can reduce building deformations. Flexural deformations are predominately induced by tunnel excavations beneath piles whereas horizontal strains at the ground level are negligible when a continuous foundation is included. Furthermore, it is illustrated that results based on buildings modelled as equivalent beams can differ considerably compared to when they are modelled as framed structures. Simple design charts are provided to estimate horizontal strains and deflection ratio modification factors based on newly defined relative axial and bending stiffness parameters which account for the presence of the piles.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/240769

Micropile foundation subjected to dynamic lateral loading
Procedia Engineering
Autore/i: Capatti, M. C.; Roia, D.; Carbonari, Sandro; Dezi, Francesca
Editore: Elsevier Ltd
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Thanks to their ease of installation, even in access-restricted spaces, micropiles are increasingly adopted for the seismic rehabilitation of existing structures. Moreover, both vertical and inclined micropiles are often used as foundation system for new constructions, ground improvements and many other applications. In order to deepen the knowledge of the dynamic behavior of those systems under horizontal loading, an extensive experimental study was carried out in an alluvial silty soil deposit on two single vertical micropiles and on a group of four inclined micropiles connected at the head by a concrete cap. Several testing procedures are exploited, in order to investigate the dynamic behavior of micropiles under different loading conditions and increasing force level, with special attention on the role of execution techniques and foundation configuration.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251327

Nonlinear response of bridge piers on inclined pile groups: The role of rocking foundation input motion
Procedia Engineering
Autore/i: Carbonari, Sandro; Morici, M.; Dezi, F.; Leoni, G.
Editore: Elsevier Ltd
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This paper presents first results of an on-going research focused on the effects of piles layout and inclination on the nonlinear seismic response of bridge piers. The analysis methodology, based on the substructure approach, is firstly presented. The soil-foundation system is studied in the frequency domain according to a numerical model developed by the authors while the inertial interaction analysis of the superstructures is carried out in the time domain to capture the nonlinear structural behaviour. A suitable lumped parameter model is used to approximate the frequency dependent behaviour of the soil-foundation impedances in the time domain analyses. The procedure is applied to some case studies constituted by single bridge piers founded on medium stiff and soft clayed soil deposits. Pile groups with piles of different inclinations are considered, as well as piers with different fundamental periods and yielding bending moments of the base cross sections, to simulate systems with different ductility capacity. Analyses results show the key role of the foundation rocking on the superstructure response and demonstrate that inclined pile foundations may have a significant impact on the superstructure response, reducing the pier head displacements and ductility demand.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251326