Operational Model Pozzuoli: Dynamic Monitoring with Accelerometers

The phenomenon of bradyseism in the Campi Flegrei represents a complex challenge for the safety of existing constructions. In this context, the Municipality of Pozzuoli has initiated an innovative dynamic monitoring project on sample buildings, leveraging advanced technologies and an integrated approach.

The article illustrates the functioning, objectives, and tools used within the Operational Model Pozzuoli, designed to support prevention, management, and structural assessment activities of the built environment in a seismically vulnerable area.

Description and objectives of the Operational Model Pozzuoli

The Municipality of Pozzuoli^[1] has entrusted the EDILTEST S.r.l. Laboratory^[2] with the implementation of an “Operational Model Pozzuoli” for monitoring Sample Buildings to support the management of control and monitoring activities of the built environment in the Municipality, an area subject to slow ground deformation known as bradyseism, with the aim of implementing a control procedure and estimating the evolution of damage conditions of the built environment due to seismic phenomena associated with bradyseism.

The development and implementation of the Operational Model, conducted with the scientific consultancy of Prof. Luigi Petti^[3], involves a multi-scalar and multi-level approach based on the Dynamic Monitoring of Sample Buildings described by Digital Models in the usBIM.geotwin environment. The initial phase involves monitoring the first three buildings with accelerometric networks based on Dewesoft^[4] technology. The monitoring, on request or triggered (i.e., under seismic conditions), will allow for the control of the evolution of the main parameters of dynamic behavior, including main vibration frequencies and modal shapes, as well as support and calibrate the construction of Digital Models for the development of Digital Twin.

The importance of structural monitoring

The acquisition of data on the behavior of existing constructions in operation and under stress actions – with particular attention to seismic events – represents an increasingly relevant and strategic opportunity. A thorough understanding of the structural response of these constructions can be effectively pursued through structural health monitoring (SHM) systems, which are based on the integration of distributed sensor networks, data acquisition and storage systems, infrastructures for information transmission – even to remote processing platforms – and advanced software procedures for the analysis, diagnosis, and interpretation of measurements ^[5,6,7].

The regulatory evolution, which has introduced fundamental concepts such as nominal life, usage classes, and specific requirements for certain types of works, underscores the importance of continuous and documented knowledge of the “life” of the construction. In this perspective, monitoring represents an essential tool for detecting over time the static, dynamic, and environmental conditions to which the structure is subjected. This is even more important in complex contexts such as the Flegrean Area, where a bradyseismic phenomenon has long been in place, causing continuous seismic effects.

As clearly highlighted by the regulations and industry guidelines, the main objectives of monitoring the built environment can enable:

1. Improvement of knowledge of structural behavior: through the direct correlation between acting forces, deformative states, and calculation models used in design, it is possible to refine technical predictions and increase the reliability of structural analyses;
2. Timely detection of anomalies: continuous monitoring allows for the identification of early signs of structural degradation, both due to cyclic phenomena (e.g., material fatigue) and as a result of exceptional events such as earthquakes, environmental impacts, or anthropogenic stresses;
3. Support for the management and maintenance of works: the data obtained provide a solid basis for making informed decisions in the management of constructions, planning predictive or extraordinary maintenance interventions more efficiently.

Dynamic analysis

The objective of the Operational Model Pozzuoli is to allow for a rapid estimation of the evolution of damage as a consequence of the numerous seismic phenomena related to the ongoing bradyseism, analyzing the evolution of the main parameters that describe the dynamic response of buildings and comparing the seismic demand in terms of base acceleration with their resistance.

The thorough knowledge of structural behavior also represents a crucial aspect for a reliable assessment of the safety of existing constructions. In particular, the acquisition of real data through monitoring can allow for:

• reducing uncertainties related to structural models, often based on simplified assumptions or incomplete information regarding materials, construction details, and boundary conditions;
• directly correlating acting forces (static, dynamic, environmental loads) with the actual response of the structure (deformations, displacements, accelerations), verifying the adequacy of design assumptions and analytical models used;
• recalibrating mechanical parameters through the use of updated models, supported by in situ measured data, allowing for analyses that are more consistent with the actual behavior of the work;
• assessing the residual load-bearing capacity based on the response observed over time, also considering any modifications, degradations, or interventions that have altered the original structural characteristics.

Ultimately, such an approach allows for overcoming purely theoretical and regulatory logic, moving towards a performance verification based on evidence, which integrates numerical modeling and experimental measurements. In an area where constructions are subjected to repeated cyclic stresses due to bradyseism, the ability to intercept even minimal variations in structural response is essential for assessing the impact of ongoing events on the safety of constructions.

In the case of Pozzuoli, the data collected and the information processed are made available almost in real-time to the Municipality thanks to the implementation of a usBIM.geotwin platform. In this way, the increase in knowledge, in addition to representing support for the Municipality of Pozzuoli in managing ongoing phenomena, constitutes a continuous informational basis that can be integrated into asset management systems for:

1. Planning predictive maintenance interventions, reducing costs and risks compared to reactive management;
2. Prioritizing resources based on the actual state of stress and degradation of constructions;
3. Documenting the evolution of structural behavior over time, also in relation to extreme environmental events;
4. Supporting strategic decisions of local authorities regarding evacuations, closures, safety measures, or consolidations, based on objective technical evidence.

Technologies used: Dewesoft and usBIM.geotwin

The monitoring networks implemented on the Sample Buildings have been developed using the Dewesoft platform, an integrated solution for the real-time acquisition, analysis, and management of structural and environmental data. In particular, robust technologies have been chosen, involving the use of low-noise calibrated sensors, typically used in complex industrial environments, with immediate expansion and reconfiguration capabilities in case of changes in actual conditions.

Dewesoft acquisition chain

The Dewesoft acquisition chain ensures microsecond data synchronization, guaranteeing high accuracy of signals generated by all channels. Each unit is also certified to operate in environments with high electromagnetic interference and in contexts where high robustness and reliability are required, making it ideal for critical applications such as the railway, industrial, and aerospace sectors, where signal reliability is essential.

Environments with high electromagnetic interference

The platform usBIM.geotwin has been configured to offer a Data Sharing Environment (ACDat) for the digital management of processed data and information, allowing for the publication and sharing of data and documents in compliance with industry standards. This enables the management of Digital Twins, thanks to a technology based on a dynamic and bidirectional integration between the openBIM^® system and the GIS system. In particular, the platform dynamically integrates openBIM^® models and processes with maps, scenes, and GIS functions (ArcGIS^® by Esri) to build and manage Geospatial Digital Twins without dimensional limits. Furthermore, the system offers a unified environment to view individual analysis objects in a detailed geospatial context, seamlessly integrating the openBIM management platform with the GIS, without data import. It is possible to manage IFC/openBIM^®, BIM/3D, point clouds, textured meshes, etc. that are geolocated and integrated with the GIS.

Integration of openBIM models, maps, scenes, and GIS functions

The Operational Model Pozzuoli has been designed to enrich the GIS with geometric information and data (BIM, IoT, FM, etc.) of buildings and infrastructures for a complete digital representation of the built environment.

Watch the interview with Prof. Luigi Petti to delve into the development and implementation of the Operational Model Pozzuoli and its multiscale and multilayer approach based on usBIM.geotwin digital models.

References

[1] The Municipality of Pozzuoli, under the guidance of the Mayor, Eng. Luigi Manzoni, has formally initiated and promoted the “Operational Model Pozzuoli”. The primary responsibility for the strategic management and executive coordination of this civic initiative has been assigned to the offices directed by the Manager Arch. Agostino di Lorenzo, who relies on the professional contribution of a qualified internal team, composed of Dr. Maria Cristina Gioia, Dr. Vittoria Scotto Rosato, and Arch. Nicola Manzo.

[2] The EDIL-TEST S.r.l. Laboratory, www.ediltest.it is one of the first Laboratories Authorized by the Ministry of Public Works pursuant to art. 20 of Law 1086/71, established in 1977 and currently equipped with ministerial concession according to article 59 of DPR 380/2001 and authorization according to Circular 633/STC of 03/12/2019. Over the years, the Laboratory has already provided its services for public works of national interest, Colosseum, Certosa di Padula, Basilica of St. Francis of Assisi, Church of St. Anna of Pietrelcina, Certosa di San Giacomo in Capri, Morandi Towers in Messina, Court of L’Aquila, Viaduct Rio Faldo and Rio Gamberi (Autostrade per l’Italia).

[3] Prof. Luigi Petti, a lecturer at the University of Salerno https://docenti.unisa.it/004657/home, teaches, among other subjects, MONITORING AND INSPECTION OF ROAD ARTWORKS. He is responsible for numerous research activities and/or services for the surveillance, monitoring, AUDIT, and risk analysis of complex structures and systems, such as SS691, RA02 Motorway Junction, A3 Motorway, Naples Bypass, Archaeological Parks of Paestum and Velia, Archaeological Park of Pompeii, Historical Center of Palermo, West Gate Area Salerno, as well as the analysis of complex structures such as, for example, the DIVERTORE components of the DEMO project (EUROFUSION). He participates in the work of the UNI/CT 021/GL08 working group “Monitoring of structures”. www.lacelab.net

[4] Dewesoft is a company that provides measurement and testing tools whose headquarters is located in Slovenia, https://dewesoft.com/it. Design, manufacturing, and testing are carried out directly at the headquarters; the calibration of the systems is performed by internal laboratories certified according to ISO 9001 and ISO 17025 standards. The main fields of application are industrial, automotive, aerospace, acoustic, civil, and electrical. The plug-and-play instrumentation offers the possibility to create complex analysis systems, while being easy to configure, with high accuracy and precision, and the acquisition software can be used for “real-time” data analysis or post-acquisition.

[5] Petti, L.; Lupo, C.; De Gaetano, C.M. A “Methodological Framework for Bridge Surveillance”. Appl. Sci. 2023, 13, 4975. https://doi.org/10.3390/app13084975

[6] Zuchtriegel, G.; Petti, L.; Calvanese, V.; De Gaetano C.M.; Lupo, C.; Spinosa A.; Zambrano, A., “The Pompeii sustainable management model”, e-Journal Pompei, 2024, https://pompeiisites.org/wp-content/uploads/28_E-Journal-The-Pompeii-sustainable-management-model-2.pdf

[7] Petti, L.; Lupo, C.; D’Angelo, T.; Dallocchio, P.; Guizzetti, D., “An Innovative Monitoring Strategy of Ancient Temples made of An Innovative Monitoring Strategy of Ancient Temples made of Rigid-Block Structures”, Sciencedirect Procedia Structural Integrity 64 (2024) 637–644, 2452-3216 © 2024, ELSEVIER