Gianni Bartoli

University of Florence | UNIFI · Dipartimento di Ingegneria Civile e Ambientale (DICEA)

Cultural heritage structures, that can be considered as the assemblage of rigid bodies (statues, pulpits, etc.), are susceptible to overturning in case of seismic events, with the potential loss of invaluable masterpieces. Therefore, the response under ground motion and their intrinsic vulnerability opened a debate among the scientific community ab...

The paper introduces recent results of experimental activities carried out on the Tribuna of the Galleria dell’Accademia di Firenze (Italy) where the Michelangelo’s David is exhibited to the public. The work aims to investigate the dynamic behaviour of the Tribuna through the analysis of the accelerations measured by two triaxial stations roving in...

Model updating procedures are commonly used to identify numerical models of a structure to be subsequently used for reliable assessment of its behaviour under environmental loads. In the case of historic masonry buildings, the uncertainties that are involved in the knowledge process (material properties, geometry, boundary conditions, etc.) can sev...

This paper reports on a pilot project for long-term structural health monitoring of historical city gates. This structural typology is what today remains of the defensive structures that characterised the medieval centres of many European cities. Even though in the last years the scientific community has paid great attention to the structural analy...

Given the importance recently assumed by permeable building envelopes in modern building architecture, this work addresses the aerodynamic effects of a screen placed close to the front face of a prismatic tall building with a square base. The screen is non-porous and covers the entire building face, but it is open on the lateral sides so to create...

This paper reports an application of wireless sensor network technology to the long-term monitoring of a historic tunnel-like masonry structure in Italy. The monitoring was performed within the activity of a research project aimed at providing a general framework to check the structural health of heritage structures and real-time detect any potenti...

Reasonable success has been obtained in the literature using Tamura's nonlinear wake-oscillator model to predict the combined instability arising from the interference of vortex induced vibration and galloping. However, the physical arguments concerning the near-wake behavior, which is a strong point of this model, have never been carefully examine...

Many efforts have been made in the last decade to define Automated Operational Modal Analysis (AOMA) procedures able to process large datasets from long-term monitoring systems. However, some issues are still open and further studies on this topic are needed; in particular following points should be better investigated: i) controlling the tuning pa...

Traffic-induced vibration is one of the main causes of small (often only cosmetic) damages for Heritage buildings. The heavy public road-transport, often very close to these structures, may lead to fatigue phenomena due to induced continuous vibrations and consequently damages. Even if all the International Standards agree to define the velocity—ex...

Wind‐tunnel experiments were performed to study the wind characteristics on a parked wind turbine downwind of three types of hill and over a flat terrain. The focus of the study is on comparing wind characteristics on (a) a wind turbine standing alone and (b) this same type of wind turbine embedded in a wind farm. Particular emphasis is placed on t...

A novel approach to full-aeroelastic model design is presented, considering continuous structures and coupled modes. Its validity is proven by building a full-aeroelastic CAARC standard tall building model featuring 12-degrees-of-freedom at 1:360 scale. A complete description of its design, manufacturing, tuning, and dynamic identification is repor...

The scientific community is hardly working to propose reliable methodologies of analysis and non-invasive technologies of investigation to assess the current state of conservation of historic buildings to verify their ability to resist future threats. These structures, mostly made of masonry, are difficult to assess due to the heterogeneity of mate...

Urban trees can play a crucial role in developing sustainable, safe and resilient cities, but at the same time they can pose risks. With an engineering approach, the study deals with a procedure able to quantify the risk that a tree subjected to the action of extreme wind events, without (windstorm) or with (rainstorm) ongoing precipitation, can ca...

Galloping instability can potentially threaten the modern launching of steel-concrete composite bridge girders, due to light weight and bluff shape of the steel box, which is normally launched first. A bridge deck with typical open cross section was selected and investigated in smooth flow through wind tunnel techniques. Aeroelastic tests showed th...

Small Darrieus vertical-axis wind turbines (VAWTs) have recently been proposed as a possible solution for adoption in the built environment as their performance degrades less in complex and highly-turbulent flows. Some recent analyses have even shown an increase of the power coefficient for the large turbulence intensities and length scales typical...

The recent developments of micro-electro-mechanical systems and wireless sensor networks allow today the use of low-cost and small-size sensors for continuous monitoring of civil structures. Both these features are very important for the low impact of the sensor grid in heritage structures, ensuring a low-cost and sustainable dynamic monitoring sys...

The new Italian building code, published in 2018 [MIT in NTC 2018: D.M. del Ministero delle Infrastrutture e dei trasporti del 17/01/2018. Aggiornamento delle Norme Tecniche per le Costruzioni (in Italian), 2018], explicitly refers to the Italian “Guidelines for the assessment and mitigation of the seismic risk of the cultural heritage” [PCM in DPC...

The manuscript provides a wide database for historic masonry towers collecting their modal, mechanical and geometrical features. This large amount of data was collected according to a literature review, then summing up as many as 56 different case studies. The collected data was then used to identify the main physical parameters influencing the mod...

The mistake to be corrected is the one named “1” in the attached pdf (i.e. to add the subscript ”,e” to the symbol “f1” at the beginning of the second row of Table 8).

This paper discusses the first results of an ongoing two-year research activity aimed to identify the actual dynamic behavior of the Pulpit of Giovanni Pisano in Pistoia in order to design a long-term structural health monitoring system. First steps of the research have foreseen a Photogrammetric and Terrestrial Laser Scanner (TLS) survey of the st...

This paper represents an expert view from Europe of future emerging technologies within the wind energy sector considering their potential, challenges, applications and technology readiness and how they might evolve in the coming years. These technologies were identified as originating primarily from the academic sector, some start-up companies and...

Seismic assessment of existing masonry structures requires a numerical model able to both reproduce their nonlinear behaviour and account for the different sources of uncertainties; the latter have to be dealt with since the unavoidable lack of knowledge on the input parameters (material properties, geometry, boundary conditions, etc.) has a releva...

Turbulence is one of the main characteristics of urban flows, but its effect on the performance of small VAWTs (often used in urban wind installations) has not been thoroughly researched. This experimental study focuses in testing a H-Darrieus VAWT prototype in different turbulent conditions inside the wind tunnel, in order to study the influence o...

This paper focuses on the use of wireless sensors networks (WSN) on cultural heritage buildings for long-term monitoring purposes. This technology is highly attractive because of both the reduced dimensions of the sensors and the absence of cables, that ensures a small visual impact. In this way, the need of a long-term monitoring is addressed with...

When is demolition mandatory? To date there is a lack of specific tools and protocols enabling a rigorous scientific assessment of the deterioration level of existing structures, guiding the choice between the real possibility of renovation or the unavoidable need of demolition. In the present paper, an attempt is made to develop a protocol suitabl...

The paper presents the case study of the survey of the sail vaults of the main building of the Forest Research Institute in Dehradun. The building has been acquired with photogrammetric and laser scanner techniques during the Ground Based 3D Modelling (Photogrammetry and TLS) tutorial, at the ISPRS TC V Mid-term Symposium held in Dehradun, India in...

Vertical-Axis Wind Turbines are receiving the attention of the wind energy community for urban wind harvesting. However, their practical application is still far from maturity, due to the lack of understanding of urban flows. High turbulence is one of the main characteristics of wind in complex environments, so special attention has been paid to mo...

Recent years have seen a growing interest toward implementation and testing of structural health monitoring techniques for cultural heritage structures, and many scientific papers report on the application of operational modal strategies as an effective knowledge-based tool for vulnerability reduction of masonry buildings. Focusing on historic maso...

The aerodynamics of a two-dimensional system, composed by a rectangular cylinder and a solid screen close to the windward face, is studied by performing smooth-flow experimental tests and numerical simulations. The aim of the study is to understand if and how a relatively thin screen, placed at a distance an order of magnitude smaller than the cros...

This paper presents an interdisciplinary approach for identification and assessment of historic buildings that combines Terrestrial Laser Scanning (TLS) survey and Finite Element (FE) numerical modeling. The structural analysis of an historic building requires the development of an interconnected series of operations aimed at obtaining a satisfacto...

A first step of a broader framework, concerning the investigation of tall buildings’ dynamic response to wind load, is presented. In order to accomplish this challenging task, a well-known benchmark has been selected: the CAARC (Commonwealth Advisory Aeronautical Research Council) standard tall building. Decades of literatures on the subject make i...

This study analyses the seismic risk of a confined historic masonry tower located in Italy (San Gimignano) critically discussing the multilevel assessment path proposed by the Italian "Guidelines for the assessment and mitigation of the seismic risk of the cultural heritage". Specifically, these guidelines identify a methodological path which aims...

This study investigates the effect of angle of attack on flow-induced vibrations (FIVs) of sharp-edged rectangular cylinders. In particular, the effect of the afterbody of a rectangular cross-section with low mass ratio and the side ratio ranging from 0.67 to 1.5 is analysed by changing the angle of attack with respect to the oncoming free-stream....

A first step of a broader framework, concerning the investigation of tall buildings' dynamic response to wind load, is presented. In order to accomplish this challenging task, a well-known benchmark has been selected: the CAARC (Commonwealth Advisory Aeronautical Research Council) standard tall building. Decades of literatures on the subject make i...

The special collection of the Journal of Performance of Constructed Facilities (JPCF) is on Seismic Risk of Monumental Buildings: Outcomes of the Research Project RiSEM is available in the ASCE Library (https://ascelibrary.org/page/jpcfev/outcomes_risem). This special collection dedicated to the research project RiSEM, which is the Italian acronym...

I fenomeni localizzati di corrosione dovuti alla presenza o ingresso di cloruri nel calcestruzzo vengono individuati come i principali responsabili del deterioramento del comportamento meccanico degli elementi strutturali in C.A. Tramite l’analisi critica e il confronto di alcuni modelli proposti in letteratura per la stima della resistenza residua...

This paper discusses an approach for identification of historic buildings that combines Terrestrial Laser Scanning (TLS) survey, Deviation Analysis (DA) and Finite Element (FE) numerical modelling. The methodology is presented through the application to an illustrative case study: an early medieval period brick minaret located in Aksaray (Turkey)....

Small Darrieus Vertical-Axis Wind Turbines (VAWTs) are presently seen as a relevant research topic for the wind energy community, since they are thought to perform better than horizontal-axis rotors in the complex and highly-turbulent flow typical of the urban environment. Indeed, a preliminary wind tunnel test campaign on a H-Darrieus VAWT showed...

This study presents an innovative wind tunnel approach to evaluate the efficiency of Vertical-Axis Wind Turbines (VAWT) in turbulent flows, to study their integration in urban environments.The first part of the research is devoted to obtaining highly-turbulent wind profiles in the wind tunnel, with the use of different configurations of square grid...

Wind characteristics in wind farms situated on a hilly terrain are considerably different than on a flat terrain. This issue is particularly important in strong-wind situations, when the wind velocity exceeds 25 m/s. In those situations, wind turbines are designed to remain in the parking position (no rotation of rotor blades) to prevent damage or...

This paper discusses on the output only modal identification of historic structures. Modal identification has been carried out both in frequency and in time domain using the Frequency Domain Decomposition (FDD) and the Stochastic Subspace Iteration (SSI-data) respectively. To highlight the sensitivity of the two methods, two masonry towers under di...

This paper discusses a case of destabilizing contribution of damping, observed for a flat-plate model vibrating in the cross-flow direction (heaving) and in the rotational degree of freedom (pitching) due to the flow-induced classical-flutter instability. This aeroelastic system can be employed in energy-harvesting applications, where the power ext...

The numerical model of existing masonry buildings, especially in case of monumental constructions, must consider the unavoidable lack of knowledge and the consequent effects of the uncertain parameters (material properties, geometry, boundary conditions, etc.). In this work, a Bayesian approach is proposed to update the finite element model of maso...

This paper deals with the phenomenon of interference between vortex-induced vibration and transverse galloping, which occurs in the case of low-damped rectangular cylinders with a side ratio comprised between about 0.75 and 3. The results of a wide experimental campaign carried out in the wind tunnel are discussed, focusing on the key role played b...

Harvesting energy from two-degree-of-freedom flutter requires large-amplitude steady-state oscillations. Nevertheless, the post-critical behaviour of this aeroelasic instability is still an open issue. The present study attempts to improve its scientific understanding and to supply information for the design of more unstable solutions for energy-ha...

This study presents an innovative wind tunnel approach to evaluate the efficiency of Vertical-Axis Wind Turbines (VAWT) in turbulent flows, to study their integration in urban environments. The first part of the research is devoted to obtaining highly-turbulent wind profiles in the wind tunnel, with the use of different configurations of square gri...

This paper presents a multi-disciplinary approach for identification of historic buildings structural health with combination of Terrestrial Laser Scanning (TLS) survey, Deviation Analysis (DA) and Finite Element (FE) numerical modelling. The proposed methodology was discussed through the application to an illustrative case study: an early medieval...

The paper reports the results of a blind benchmark developed as a part of the preliminary activity of the research project RiSEM (Italian acronym for Seismic Risk on Monumental Buildings). The benchmark was aimed at comparing the results obtained with different analytical models and/or numerical analysis techniques (variational approach, finite ele...

Structural monitoring through dynamic identification has been increasingly recognized as an effective technique for assessing the health status of many structural typologies. In particular, due to the low invasiveness of this approach, it appears to be very attractive for cultural heritage buildings; among the others, especially for masonry towers...

This work investigates the flow-induced motion originating from the classical-flutter instability, and it is motivated by energy-harvesting applications. The influence of several sets of dynamic parameters is studied, improving the scientific understanding of the large-amplitude response and guiding the design of more unstable configurations. Wind-...

p>The present work presents the experimental results aimed to assess the dynamical characteristics of a cable-stayed footbridge recently built in Terni (Italy). The assessment process involved both wind tunnel and full-scale experimental tests, and relied on the fruitful interaction between designers and academic experimenters. The wind-tunnel stud...

Energy harvesting from flow-induced vibrations is a recent research field, which considers a diverse range of systems, among which two-degree-of-freedom flutter-based solutions were individuated as good candidates to obtain high energy performance. In the present work, numerical linear analyses and wind-tunnel tests were conducted on a flat-plate s...

Effect of turbulence on the large vibrations following flutter stability in the framework of energy harvesting.

This paper summarizes the results of a two-day dynamic monitoring of Michelangelo's David subject to environmental loads (city traffic and pedestrian loading induced by tourists visiting the Accademia Gallery). The monitoring was carried out by a no-contact technique using an interferometric radar, whose effectiveness in measuring the resonant freq...

This paper focuses on the seismic risk assessment of historic masonry towers according to the Italian “Guidelines for the Assessment and Mitigation of the Seismic Risk of the Cultural Heritage.” The latter identifies a methodology of analysis based on three different levels of evaluation, according to increasing requirements on the structural knowl...

Discrete rigid blocks interacting through nonlinear elastic damageable interfaces are used to model the global behavior of a medieval masonry tower under seismic actions. The seismic vulnerability assessment is carried out by nonlinear static analysis (NSA) and incremental dynamic analysis (IDA), whose results are compared. It is confirmed that NSA...

The paper focuses on the analysis of the outcomes of some experimental tests carried out in San Gimignano (Siena, Italy), aimed at measuring the natural frequencies of the medieval masonry towers still present in the historic city center. Information on the investigated towers was inserted into a wider database that collected dynamic, mechanical, a...

The design of modern bridge towers tends toward more and more complex-shaped (tapered and/or inclined cantilevers, etc.) and lighter structures. Consequently, the wind effects are often assessed through full-aeroelastic tests, even for small/medium-span flexible bridges. The lightness of these structures, together with a bluff shape, give rise to a...

The aerodynamics of a stationary two-dimensional cylinder with rectangular 5:1 cross section is the object of an international experimental and numerical benchmark study (BARC). The unsteady flow past such a bluff body is governed by the impinging shear-layer instability mechanism, which is also responsible for potential flow-induced vibrations. Th...

In the framework of energy harvesting from flow-induced vibrations, understanding the behaviour of dynamic systems under high levels of damping is a key issue. In particular, this work refers to two-degree-of-freedom elongated rectangular plates prone to the aeroelastic instability of classical flutter. The effect of heaving damping was studied thr...

This paper presents an application of a methodology for the seismic vulnerability reduction of masonry towers by reversible prestressing. The approach is applied on a medieval tower located in San Gimignano, Italy, which is considered as a world heritage site. The 3D FE models are calibrated with experimental data and assessed by nonlinear static a...

Within 2014, a research project promoted by the Opera del Duomo of Santa Maria del Fiore in Florence allowed to make new evaluations about the conservation of the Baptistery of San Giovanni. The research project was developed by an interdisciplinary team composed of experts in conservation and restoration, architects, geologists, archaeologists and...

The assessment of seismic performance of historical masonry towers is complicated by the lack of experimental data on the material properties. The peculiarity of these structures and their historical value render difficult performing experimental tests, particularly destructive ones. For each mechanical parameter, only reasonable intervals can be d...

Within 2014, a research project promoted by the Opera del Duomo of Santa Maria del Fiore in Florence allowed to make new evaluations about the conservation of the Baptistery of San Giovanni. The research project was developed by an interdisciplinary team composed of experts in conservation and restoration, architects, geologists, archaeologists and...

The phenomenon of interference between vortex-induced vibration (VIV) and galloping in the transverse degree of freedom was studied in the wind tunnel in the case of a spring-mounted slender rectangular cylinder with a side ratio of 1.5 having the short side perpendicular to the flow. The tests were carried out in a wide Scruton number range, start...

The last surveys and inspections carried out on the wooden tie-rods encircling the two domes of the Baptistery of San Giovanni and of the Cathedral of Santa Maria del Fiore in Florence, promoted by the Opera del Duomo of Florence, allow to make new considerations on these monuments and on the effectiveness of these strengthening techniques. In this...

This paper presents the results of an interdisciplinary study carried out on Brunelleschi’s Cupola of Santa Maria del Fiore in Florence, Italy, one of the most emblematic masonry domes in the world. The cupola has been affected since the beginning of its construction by a widespread cracking phenomenon, and several studies were done over the centur...

In this paper, a rare example of comparison between sectional and full-aeroelastic model tests is presented. Interestingly, the experiments were conducted in two very different wind tunnel facilities by different research teams. The study concerns two long-span steel arch structures recently built in Milan, Italy, for Expo 2015 World Fair. The stru...

Masonry towers are diffused through the whole European territory; these structures show unique typological and morphological features that might lead to severe effects under horizontal loads (such as the earthquake loads). Recently, the seismic assessment of historical masonry structures has been specifically taken into account by the Italian Guide...