Research.
Our research is focused on:
(i) Structural Health Monitoring (SHM), with applications of vibration-based methods and smart sensing technologies
(ii) Non destructive testing and evaluation
(iii) Structural control
(iv) Earthquake protection of civil structures.
(i) Structural Health Monitoring (SHM), with applications of vibration-based methods and smart sensing technologies
(ii) Non destructive testing and evaluation
(iii) Structural control
(iv) Earthquake protection of civil structures.
Research:
Commercial brochures of MOVA and MOSS (in Italian and English)
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MOVA-MOSS: Software solutions for comprehensive vibration-based SHM
MOVA and MOSS represent two software solutions for the integral SHM of structures. Originally developed in MATLAB environmental, C++ standalone versions have been recently developed. MOVA is a software for Operational Modal Analysis, and includes multiple system identification techniques such as FDD, DATA-SSI, COV-SSI, p-LSCF, ERA and blind source separation. An intuitive graphical user interface allows for animating complex mode shapes, stabilization diagrams, clustering analysis, along with diverse data and graphics export options. On the other hand, MOSS is a software for automated OMA and damage detection for SHM. The code allows for automatically managing data recordings of ambient vibrations and environmental variables. In addition, the code includes multiple regressive models for conducting damage identification, as well as a package of surrogate modeling. Trial versions will be available soon. For further information, please contact [email protected], [email protected]
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Self-sensing RC structures with nanomodified cementitious composites
The Research concerns the development of a strain-sensitive Nano-modified Cementitious Sensors and Structures for applications in permanent structural health monitoring (SHM) systems. SHM systems are becoming essential to identify possible incipient damages and structural issues, particularly important for the safety of the users both in service conditions and after critical events, to increase safety and minimize maintenance costs of strategic structures and infrastructures. Recent advances in the field of nanotechnologies show a promise towards the development of strain-sensitive cementitious materials and special coatings. A. D’Alessandro, F. Ubertini, E. García-Macías, R. Castro-Triguero, A. Downey, S. Laflamme, A. Meoni, A. L. Materazzi, Static and Dynamic Strain Monitoring of Reinforced Concrete Components through Embedded Carbon Nanotube Cement-Based Sensors, Shock and Vibration, Volume 2017 (2017), Article ID 3648403, 11 pages. |
Smart brick
The research is aimed to propose and develop the radically new "smart clay brick", that is, a piezoresistive nanocomposite clay brick able to sense its internal state of strain. This technology has the potential of providing an effective innovative solution for SHM of masonry structures, overcoming the limits of existing sensing solutions. The vision is that of inserting a few smart bricks at critical locations inside the structure, so as to carry out the following tasks: (i) monitoring the state of stress in the masonry, (ii) detecting active failure mechanisms caused by an earthquake or other exceptional loading events and (iii) carrying out vibration-based monitoring. Meoni A., D’Alessandro A., Cavalagli N., Gioffré M., Ubertini, F., Shaking table tests on a masonry building monitored using smart bricks: damage detection and localization (2019) Earthquake Engineering and Structural Dynamics, 1–19, https://doi.org/10.1002/eqe.3166. |
Micro-mechanical modeling of nano-composites
Electromechanical modelling of composite materials doped with Carbon NanoTubes (CNTs). The research is aimed at devising efficient theoretical approaches capable of shedding some light into the physical mechanisms underlying the behavior of these composites and, as a result, assisting the design of smart and high-performance CNT-based composites. More recently, a new line of research on the application of Seismic Interferometry for the monitoring of large scale structures has been opened. This approach consists of considering the dynamic response of structures as a set of moving waves. In such a way, it is possible to develop damage identification systems based on the automated detection of delays in the identified wave velocities. García-Macías E., D'Alessandro A., Castro-Triguero R., Pérez-Mira D., Ubertini F., Micromechanics modeling of the uniaxial strain-sensing property of carbon nanotube cement-matrix composites for SHM applications (2017) Composite Structures, 163, pp. 195-215. |
Vibration-based continuous minitoring for earthquake damage diagnosis of precast reinforced concrete buildings
Precast reinforced concrete technology is recognized as an efficient construction method, mainly adopted for industrial and commercial buildings. Existing precast structures often reveal a significant vulnerability and an insufficient safety level against seismic actions, also related to the low level of hyperstaticity. Hence the importance of the assessment of their seismic behavior and the need of tracking their dynamic characteristics with time through structural health monitoring techniques clearly point out. With this aim, vibration-based continuous monitoring systems, already applied successfully to historical buildings, bridges and other types of structures, can also be adopted for precast RC buildings, for their capability of highlighting if they have undergone permanent damage after an earthquake or if they are accumulating damage during a seismic sequence. |
Life-cycle cost-based design of wind excited tall buildings
The early stages of the design process of wind-excited tall buildings involve several decisions on structural typology, shape, orientation, optional control system, type and distribution of nonstructural elements. Focusing on this last aspect, the main issue addressed in this reaserch topic is the systematic comparative cost-based analysis accounting for the damage at the nonstructural system level, induced by extreme wind loads. In this context, an automated and computationally efficient procedure named Life-Cycle Cost Wind Design (LCCWD) is developed for the design of tall structures. All the key aspects related to wind engineering are considered: the characterization of the wind load and of the aerodynamic structural response uncertainty, the probabilistic analysis of non-structural damages, the choice of an effective control system considering technical and economic aspects, the ccupants’ discomfort wich can lead to business interruptions and consequent downtime losses. Ierimonti, L., Venanzi, I., Caracoglia, L., Materazzi, A.L., Cost-Based Design of Nonstructural Elements for Tall Buildings under Extreme Wind Environments (2019) Journal of Aerospace Engineering, 32 (3), art. no. 04019020. |
Earthquake-induced damage identification in heritage masonry structures
There is a great awareness of the importance of conservation and safeguarding of heritage buildings as they constitute vital assets with manifold positive socio-economic effects. According to the World Heritage List drawn up by UNESCO, nearly half of the heritage sites are located in Europe, where Italy heads the list with 54 sites. It is precisely in Italy where the conservation of heritage buildings is of paramount importance due to its high seismicity. In this context, an important research line of the group focuses on the application of vibration-based Structural Health Monitoring (SHM) techniques for earthquake-induced damage detection in heritage masonry structures. These techniques are based upon the monitoring of structural vibrations under operational conditions with no external excitation sources, so that a minimal impact on the monitored structure is achieved. Our research efforts focus on the identification (detection, localization and quantification) of earthquake-induced structural pathologies through the continuous monitoring of heritage buildings, relating the origin of structural damage to permanent variations in the modal properties (resonant frequencies, mode shapes and damping properties) of the structure. Ubertini, F., Cavalagli, N., Kita, A., & Comanducci, G. (2018). Assessment of a monumental masonry bell-tower after 2016 Central Italy seismic sequence by long-term SHM. Bulletin of Earthquake Engineering, 16(2), 775-801. |
Vibration-based Structural Health Monitoring (SHM) for the condition assessment of infrastructures
An important research line of the group concerns the application of SHM techniques through Operational Modal Analysis (OMA) for the condition assessment of infrastructures. These techniques are based upon the monitoring of structural vibrations under operational conditions, through which the modal properties of the structure are identified (resonant frequencies, mode shapes, and damping properties). These properties offer valuable information about the integrity of the monitored structure, since they reflect its mass and stiffness properties. Therefore, the presence of alterations in the normal performance of the structure (such as structural damage) can be inferred through the proper analysis of this information, and ad-hoc corrective interventions can be scheduled and implemented before these alterations pose a risk to the structural safety. In this light, this research line primarily focuses on the development and implementation of automated OMA-based SHM systems for the continuous assessment of infrastructures. Moreover, through the simultaneous monitoring of environmental conditions (e.g. temperature, humidity), this research line is aimed at identifying intrinsic modal features unaffected by normal operating conditions that provide a clear indicator for damage identification. Ubertini, F., Gentile, C., & Materazzi, A. L. (2013). Automated modal identification in operational conditions and its application to bridges. Engineering Structures, 46, 264-278 |
Active Base Isolation of Museum Artifacts under Seismic Excitation
Damage to statues and works of art housed in museums and expositions has been observed in many cases during strong earthquakes. This type of damage is often irreparable and produces inestimable losses to the historical and artistic heritage. For this reason, the seismic protection of artifacts has gained increasing attention during recent years. Passive protection devices have been adopted in many cases and, if well designed, are effective in mitigating the seismic loads transmitted to the statue from the base, but in most cases the isolator’s performance is dependent on the characteristics of the isolated structure and on the location within the building. To overcome these drawbacks, the main objective of the research topic is to investigate the possibility of adopting base active control for the seismic protection of works of art which allows the adaptability to different artifacts and locations within the building. Venanzi, I., Ierimonti, L., Materazzi, A.L., Active Base Isolation of Museum Artifacts under Seismic Excitation (2018) Journal of Earthquake Engineering, pp. 1-22. |