10.6092/issn.1973-9494/17364
application/pdf
1973-9494
17364
en
Fabrizio Cumo
https://creativecommons.org/licenses/by/3.0
Conservation Science in Cultural Heritage
extreme events prevention
Using Digital Twin Models (DTM) for managing, protecting and restoring historical buildings
Text.Serial.Journal
https://conservation-science.unibo.it/
22
Articles
2023-07-20
2023-06-23
2023-07-20
2023-07-20
425-445
CSCH
Fabrizio Cumo
2022
10.6092/issn.1973-9494/17364
425
Dipartimento di Pianificazione, Design, Tecnologia dell'Architettura, Sapienza Università di Roma
1973-9494
extreme events prevention
en
445
Using Digital Twin Models (DTM) for managing, protecting and restoring historical buildings
https://conservation-science.unibo.it/article/download/17364/16510
22
U    SING DIGITAL TWIN MODELS (DTM) FOR MANAGING,
     PROTECTING AND RESTORING HISTORICAL BUILDINGS


   Federico Cinquepalmi *
   Dipartimento di Architettura e Progetto, Sapienza Università di Roma, Italy

   Fabrizio Cumo
   Dipartimento di Pianificazione, Design, Tecnologia dell’Architettura, Sapienza
   Università di Roma, Italy

   Keywords: Digital Twin for heritage, built environment management, climate change
   impacts, extreme events prevention



   1. Introduction

    In Italy, historical buildings are particularly vulnerable to extreme events, such as
earthquakes, floods, and landslides often connected with extreme climatic events, with-
out mentioning all the risks connected with vandalism, wars, and acts of terrorism [1-3].
Fragility is due in part to the age of most of these buildings, as well as to their construc-
tion materials and techniques [4]. Most of the historical buildings in Italy were built us-
ing unreinforced masonry, which can be prone to collapse or severe damage in the
event of an earthquake [5-7]. In addition, some buildings may have been constructed
on unstable ground or in flood-prone areas such as the case of the Leaning Tower of
Pisa, which further increases their vulnerability to natural disasters.
    Such vulnerability requires the use of all the most advanced technologies, both for
monitoring and management, and the most promising one is currently the use of Digital
Twin Models (DTM). Digital Twins are defined as virtual replicas of physical objects,
systems, or processes that are used to simulate, monitor, and optimise their real-world
counterparts [8]. They have become increasingly important in various industries, in-
cluding the built environment, because of the numerous benefits they offer [9]. In gen-
eral, Digital Twins allow for better understanding and management of complex sys-
tems, as they provide real-time data and insights that can help identify and address
issues before they become significant problems. This can result in improved efficiency,
reduced downtime, and cost savings. Additionally, Digital Twins can facilitate collabo-
ration among different stakeholders and enable more informed decision-making.
    In the context of the built environment, Digital Twins can have a significant impact
on the design, construction, operation, and maintenance of buildings and infrastruc-
ture. By creating a Digital Twin of a building or infrastructure project, architects, engi-
neers, and contractors can visualise and test different design options, evaluate energy
and resource usage, and identify potential safety hazards before construction begins
[10–12]. DTMs can also be used to facilitate the restitution of a historical building after




   * Corresponding author: federico.cinquepalmi@uniroma1.it
                                                                                                                                    an extreme event. By providing a detailed virtual representation of the building, experts
Federico Cinquepalmi, Fabrizio Cumo - Using Digital Twin Models (DTM) for managing, protecting and restoring historical buildings



                                                                                                                                    can better plan and provide for the restoration process, ensuring that the building is
                                                                                                                                    restored to its original conditions as quickly and effectively as possible. Overall, using
                                                                                                                                    DTMs for managing historical buildings offers a range of benefits, from improved main-
                                                                                                                                    tenance and preservation strategies to more effective emergency response and resto-
                                                                                                                                    ration efforts. As such, it is likely to become an increasingly important tool for the
                                                                                                                                    preservation of the vast cultural heritage of Italy in the years to come [13–15]1.


                                                                                                                                        1.1. A fragile heritage to be preserved: the Italian case study

                                                                                                                                         To address the challenges of vulnerability of built heritage, experts in Italy are in-
                                                                                                                                    creasingly turning to DTM to better understand the potential risks historical buildings face
                                                                                                                                    and so develop more effective strategies for their preservation and restoration. By creating
                                                                                                                                    virtual replicas of these buildings, experts can simulate the effects of extreme events and
                                                                                                                                    test different restoration and preservation scenarios, helping to ensure that these import-
                                                                                                                                    ant cultural assets are protected for future generations. Overall, the fragility of historical
                                                                                                                                    buildings in Italy underscores the importance of taking a proactive and collaborative ap-
                                                                                                                                    proach to their preservation and restoration. By leveraging the latest technology and
                                                                                                                                    expertise, it is possible to protect these buildings from the risks posed by extreme events
                                                                                                                                    and ensure that they continue to inspire and educate for years to come. The fragility of
                                                                                                                                    these buildings has been highlighted by several recent events in Italy (Figure 1).




                                                                                                                                    Figure 1. Maps of flooding (left) and landslide (right) risks, threatening cultural heritage features
                                                                                                                                    in Italy as evaluated by the Italian National Agency for environmental protection and research, the
                                                                                                                                    number in the coloured circles is the number of assets at risk [16].


                                                                                                                                        In 2016, a series of earthquakes struck central Italy, causing widespread damage
                                                                                                                                    to historic towns and villages2. Many buildings, including churches, palaces, and other
                                                                                                                                    landmarks, were either partially or completely destroyed. Similarly, in 2018, heavy rain-


                                                                                     426
fall and flooding caused significant damage to historical buildings in Venice, including
St. Mark’s Basilica, which suffered extensive water damage3. The flooding also high-
lighted the challenges of preserving historical buildings in a historical city that is in-
creasingly susceptible to rising sea levels and extreme climatic events, stressing the
importance of employing the best available technologies to improve risk management
and the response to such events (Figure 2). The 2016 earthquake in central Italy, which
struck on August 24, caused significant damage to many historic monuments and
buildings in the region; it had a magnitude of 6.2 and though centred in the area sur-
rounding the town of Amatrice (Figure 3), it was felt throughout the region. Some of the
most severely affected monuments included the Basilica of San Benedetto in Norcia,
the Cathedral of Santa Maria Argentea in Amatrice, and the Church of San Salvatore
in Campi. In many cases, entire sections of these buildings were destroyed or severe-
ly damaged, and in some other cases, entire structures collapsed 4.




                                                                                                      CONSERVATION SCIENCE IN CULTURAL HERITAGE




Figure 2. Satellite image of the flooding in Venice on November 19, 2019. The high tide levels of
flooding are measured by satellite altimetry sensors and graphically represented with blues of
different intensity (darkest blue = deepest water) [17].


    The earthquake also had a significant impact on smaller towns and villages
throughout the Abruzzo region, where many historic buildings and monuments were
highly damaged or destroyed. The Italian government and international organisations
have been working to assess the damage and develop plans for the restoration and
preservation of these cultural heritage sites; the earthquake has had a profound impact
on central Italy’s heritage, highlighting its fragility as well as the need for ongoing ef-
forts to protect and preserve these important monuments and buildings.


                                                                                                    427
Federico Cinquepalmi, Fabrizio Cumo - Using Digital Twin Models (DTM) for managing, protecting and restoring historical buildings




                                                                                                                                    Figure 3. Map of Amatrice (Italy) after the 2016 earthquake, showing damage assessment, based on
                                                                                                                                    Copernicus Satellite images and data. The parts identified in red represent destroyed buildings:
                                                                                                                                    dark orange highly damaged, light orange moderately damaged and yellow negligible to slightly
                                                                                                                                    damaged (severity scales with colour) [17].


                                                                                                                                        Several organisations, including UNESCO5 and the Italian Ministry of Culture [18],
                                                                                                                                    have launched a number of initiatives to support the recovery and restoration of these
                                                                                                                                    monuments6. In some cases, Digital Twin technology has been used to create virtual
                                                                                                                                    models of damaged structures, allowing experts to assess the extent of the damage
                                                                                                                                    and develop restoration plans. One example is the Church of SS Apostoli e Biagio
                                                                                                                                    where a digital representation of the asset has been created using common us-
                                                                                                                                    er-friendly 360° cameras and photogrammetry with LiDAR to capture geographic data
                                                                                                                                    from the site [19]. However, the work on the Church of SS Apostoli e Biagio lacks the
                                                                                                                                    control capability typical of a Digital Twin application and is nearer to a digital model
                                                                                                                                    without real-time monitoring. It is a common problem for Digital Twin applications that
                                                                                                                                    can only reach an early stage of development due to a lack of funds and a proper
                                                                                                                                    framework able to define all the parameters and digital requirements in real time that
                                                                                                                                    a Digital Twin should have. Another example is the Digital Twin developed for the
                                                                                                                                    Quadriportico of the Cathedral of San Matteo in Salerno, in Italy, where the authors
                                                                                                                                    proposed an automated analysis for the state of degradation by exploiting a solution
                                                                                                                                    that combines a graphical database and a dynamic Digital Model [20]; the Gothic
                                                                                                                                    Cathedral of Milan was also investigated using Digital Twins for the monitoring and
                                                                                                                                    study of the structural response of the building, as preventive maintenance and
                                                                                                                                    strengthening operations [21].


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    1.2. Using Digital Twins for heritage management and preservation

    The topic of Digital Twin technology for cultural heritage has been studied in detail
for museums where the already existing infrastructure can be integrated with ease in
Digital Twin applications for both the fruition of content and the monitoring of digital
data [22], asset and people monitoring [23], light control [24] and virtual reality visits
[25-26]. Digital Twins rely on a variety of enabling technologies, as shown in Table 1.

Table 1. Enabling technologies needed to a Digital Twin in order to accurately replicate physical
systems in real-time, allowing for analysis, optimization, and decision-making.


   TECHNOLOGY                                       DESCRIPTION

 Internet of Things     These sensors collect data on physical objects, such as machinery or
 (IoT) Sensors:         equipment, and transmit it to the Digital Twin.
                        Digital Twins require large amounts of storage and the possibility to
                        develop aggregated metrics for analysis and control. Cloud platforms
 Cloud Platforms:
                        are very suitable to achieve this goal, making it possible to access and
                        store data from everywhere at low latency.
 Machine Learning       AI and ML algorithms can analyse data collected by the Digital Twin
 (ML) and Artificial    providing valuable insights into how to optimise performance or predict
 Intelligence (AI)      future behaviour.
                        AR, MR, and VR can provide a visual representation of the Digital Twin,
                        allowing users to interact with it in real time. The difference between VR
 Augmented, Mixed
                        and AR is the type of environment, where AR adds virtual assets/
 and Virtual Reality
                        elements to the real-world and VR creates a virtual world to inspect a
 (AR, MR, and VR):
                        site. Instead, MR is a trade-off between the two, where the virtual and
                        the real world combine and interact with each other.




                                                                                                       CONSERVATION SCIENCE IN CULTURAL HERITAGE
                        Security in digital assets is a topic of fundamental importance to avoid
                        tampering and thefts. Nowadays the most discussed security technologies
 Security:              to support DTM are based on distributed ledger technology (such as for
                        Blockchain), quantum encryption and traditional security methods based
                        on authorizations and encryption.
                        This software is used to create and simulate the Digital Twin’s behaviour
 Simulation software:
                        in various scenarios, allowing for analysis and optimization.
                        Fog computing can be used to process data in real-time, receiving and
                        processing sensor data on site before their transmission to the cloud
 Fog Computing:
                        platform. This leads to reduced latency, lower computational power and
                        improving responsiveness.
                        5G and wireless networks provide high-speed, low-latency, and a high
 5G and 6E wireless     number of connected devices, which are essential features for real-time
 networks:              data processing and communication between Digital Twins and physical
                        systems.


   As far as the application of DT to cultural heritage management is concerned, thus,
beginning with a point-cloud model, both AI-based technology for automatic object
recognition, and ML models for system automations are used and the building must be
modelled in IFC (Industry Foundation Classes) file format. Within the model, all infor-
mation relating to the installation, maintenance and management of the individual


                                                                                                     429
                                                                                                                                    components must then be digitised, including the sensors and IoT instruments that are
Federico Cinquepalmi, Fabrizio Cumo - Using Digital Twin Models (DTM) for managing, protecting and restoring historical buildings



                                                                                                                                    physically placed inside the building to continuously monitor its condition and act on
                                                                                                                                    HVAC, lighting, hydraulic related systems, etc.
                                                                                                                                         A suitable platform must then be identified to manage the data coming from the
                                                                                                                                    physical reality; this platform will not only visualise the data in an advanced manner but
                                                                                                                                    will also contain simulation models and predictive algorithms, able to analyse the situ-
                                                                                                                                    ation in real time and plan automatic or ‘human in the loop’ strategies to deal with
                                                                                                                                    normal usage, abnormal situations, or accidental events. The visualisation of the Digi-
                                                                                                                                    tal Twin can be made more usable by using specific gaming technologies and/or aug-
                                                                                                                                    mented reality systems, which can also be used for training non-specialised workers
                                                                                                                                    for maintenance interventions in critical areas. It is worth mentioning that a digital mod-
                                                                                                                                    el alone, should not be considered as a Digital Twin, because it lacks the real-time
                                                                                                                                    monitoring and control capabilities typical of a Digital Twin.
                                                                                                                                         Digital technologies have played a significant role in the reconstruction of damaged
                                                                                                                                    buildings in Italy following natural disasters such as earthquakes, using UAV and 5G
                                                                                                                                    networks [27-28]. These technologies have been used for various purposes, including
                                                                                                                                    damage assessment, documentation, and restoration planning. Among the most prom-
                                                                                                                                    ising technologies for risk assessment and response7, satellite technologies have also
                                                                                                                                    been applied to aid in the reconstruction of damaged buildings in Italy. Satellites can
                                                                                                                                    provide high-resolution imagery and data that can be used for damage assessment,
                                                                                                                                    monitoring, and planning.
                                                                                                                                         A pertinent example of the use of satellite technology is the Copernicus Emergency
                                                                                                                                    Management Service (EMS)8 in operation since April 2012. It provides near-real-time
                                                                                                                                    satellite imagery and maps, on demand, of disaster areas, to support emergency re-
                                                                                                                                    sponse and reconstruction efforts for selected emergency situations that arise from
                                                                                                                                    natural or man-made disasters anywhere in the world. This service was used exten-
                                                                                                                                    sively following the 2016 earthquake in central Italy, providing valuable information
                                                                                                                                    about the extent of the damage and the condition of the affected buildings. Satellite
                                                                                                                                    technology can also be used to monitor and assess the ongoing stability of damaged
                                                                                                                                    buildings.
                                                                                                                                         For example, synthetic aperture radar (SAR) can be used to detect changes in the
                                                                                                                                    shape and movement of buildings over time, providing valuable information about their
                                                                                                                                    stability and potential risks. In addition, satellite technology can aid in the identification
                                                                                                                                    of new risks, such as landslides or changes in soil moisture, that may affect the stabil-
                                                                                                                                    ity of damaged buildings. This information can be used to inform restoration plans and
                                                                                                                                    prioritise reconstruction efforts. Overall, satellite technologies have been an important
                                                                                                                                    tool in the reconstruction efforts following natural disasters in Italy, providing valuable
                                                                                                                                    information about the extent of the damage, ongoing stability of damaged buildings,
                                                                                                                                    and potential risks, in order to aid restoration planning and prioritization9.


                                                                                                                                       2. The application of digital technologies for the restoration of historical
                                                                                                                                          buildings: two success stories – The Basilica of Saint Francis in Assisi (Italy)
                                                                                                                                          and Notre Dame of Paris (France).

                                                                                                                                        The Basilica of Saint Francis in Assisi, Italy, is a UNESCO World Heritage site and
                                                                                                                                    an important symbol of Christian spirituality. In 1997, the Basilica suffered significant
                                                                                                                                    damage in an earthquake which caused the collapse of several vaults and the destruc-
                                                                                                                                    tion of many frescoes and other works of art (Figure 4).


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Figure 4. The collapse of the fresco ceiling in the Basilica of Saint Francis in Assisi following the
1997 earthquake [29].


    The digital model developed for the Basilica is a comprehensive 3D model that in-
cludes detailed information about the building’s structure, materials, and historical fea-
tures. Based on data collected before the 1997 earthquake that caused significant




                                                                                                          CONSERVATION SCIENCE IN CULTURAL HERITAGE
damage to the building and especially to the frescoed vaults, the model was developed
using a combination of laser scanning, photogrammetry, and other digital imaging
technologies to create an accurate 3D model of the building’s structure, materials, and
historical features [30]10.
    To restore the basilica, experts initially employed only digital scans, moving only
later towards a true digital twin technology which allowed them to create a virtual repli-
ca of the building and simulate different restoration scenarios. Using this DTM, experts
were able to test different restoration strategies and evaluate their impact on the build-
ing’s structural integrity and aesthetic value. They were also able to identify potential
risks and issues that could arise during the restoration process, such as the need to
reinforce certain sections of the building or the risk of damage to the surviving delicate
frescoes and other works of art.
    Furthermore, after the introduction of digital technologies, the restoration process
was able to ensure that the construction site of the Basilica of San Francesco was
carried out in a safe, efficient, and effective manner [31-33]. The digital model was
used to simulate the effects of various restoration strategies, allowing researchers to
evaluate the potential outcome of different interventions before being implemented.
This approach can help to reduce the risk of unintended consequences and ensure
that restoration efforts are targeted and effective, enabling experts to preserve and
protect the building’s cultural heritage: DT technology holds many promises for the future
management of these valuable assets.


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                                                                                                                                        The Assisi Basilica construction site for restoration has been integrated with Inter-
Federico Cinquepalmi, Fabrizio Cumo - Using Digital Twin Models (DTM) for managing, protecting and restoring historical buildings



                                                                                                                                    net of Everything (IoE) technologies, which are able to monitor internal conditions by
                                                                                                                                    means of wireless sensors placed throughout the site. The Basilica has specific needs
                                                                                                                                    in terms of security, safety, management, and visitors’ services. Therefore, a specific
                                                                                                                                    infrastructure has been designed, characterised by high reliability and resilience and is
                                                                                                                                    able to operate in both critical and ordinary conditions. The infrastructure can ensure:
                                                                                                                                       •   an adequate level of security and safety to people and assets
                                                                                                                                       •   the maximum ease of utilisation, using automation systems
                                                                                                                                       •   an adequate level of reliability, resilience, and flexibility
                                                                                                                                       •   a good modularity and expandability for future upgrades, such as new services
                                                                                                                                           and sensors.
                                                                                                                                        On the other hand, the digital infrastructure contributes to reducing energy con-
                                                                                                                                    sumption and maintenance costs, transforming the digital management of the con-
                                                                                                                                    struction site for restoration into a permanent tool for the ordinary management of the
                                                                                                                                    Basilica, continuously powered by data and information coming from the building sen-
                                                                                                                                    sors and in line with the principles of a Digital Twin.
                                                                                                                                                                              The comparative construction site we decided to
                                                                                                                                                                         analyse is the reconstruction of Notre Dame Cathe-
                                                                                                                                                                         dral in Paris. On April 15, 2019, a fire broke out in the
                                                                                                                                                                         church, causing significant damage to the historic
                                                                                                                                                                         structure. The fire is believed to have started in the at-
                                                                                                                                                                         tic of the cathedral, which housed a complex network
                                                                                                                                                                         of wooden beams and trusses known as “the forest”11,
                                                                                                                                                                         the result of the restoration project led by Eugene Em-
                                                                                                                                                                         manuel Viollet le Duc [34] and was surmounted by a
                                                                                                                                                                         tall wooden spire (Figure 5). The fire burnt the antique
                                                                                                                                                                         masonry and caused the spire to collapse. Firefighters
                                                                                                                                                                         worked for several hours to contain the blaze and pre-
                                                                                                                                                                         vent its spreading to the cathedral’s bell towers and
                                                                                                                                                                         other parts of the building12 and surroundings.
                                                                                                                                                                              The use of Digital Twin technology for the Notre
                                                                                                                                                                         Dame Cathedral is expected to dramatically improve
                                                                                                                                                                         management of the construction site during the res-
                                                                                                                                                                         toration process. Several research activities have
                                                                                                                                                                         been developed based on the collected materials
                                                                                                                                                                         resulting from the debris, mainly stones and timber,
                                                                                                                                                                         and were heavily polluted due to the strong presence
                                                                                                                                                                         of lead from the ancient roof covering which had dis-
                                                                                                                                                                         solved completely as a result of the high tempera-
                                                                                                                                                                         tures of the fire and were highly toxic. In particular,
                                                                                                                                                                         the timber that had partially survived the fire allowed
                                                                                                                                                                         for a very interesting study on the paleo climatic con-
                                                                                                                                                                         dition of Europe during the Middle Ages [35].
                                                                                                                                                                              The cause of the fire was initially unclear, but in-
                                                                                                                                    Figure 5. La Fleche (the Spire) of
                                                                                                                                                                         vestigators later determined that it was likely the result
                                                                                                                                    Notre Dame, original drawing by
                                                                                                                                    Eugene Viollet le Duc for the great  of an electrical short-circuit, caused by a combination
                                                                                                                                    restoration project of the Cathedral of factors, including the age of the electrical wiring in
                                                                                                                                    (1860). The wooden Spire was         the attic of the church and the presence of inflamma-
                                                                                                                                    destroyed in the fire of 2019 [34].  ble materials such as sawdust and debris that could


                                                                                           432
have contributed to the quick spread of the fire through the cathedral’s wooden roof
(Figure 6) [37]13. The main positive results of the extensive application of Digital Twin
technology for the construction site management at Notre Dame is summarised in Table 2.




Figure 6. The collapse of the spire of Notre Dame Cathedral during the fire that broke out in 2019,
occurred during an extensive restoration programmed for the church [36].



Table 2. Construction site management phases for the Notre Dame restoration




                                                                                                         CONSERVATION SCIENCE IN CULTURAL HERITAGE
         ACTION                                          RESPONSE
                             The effectiveness of the DTM is linked to an in-depth knowledge of
                             the existing state of a building, as an optimal precondition for the
 Scanning the existing       restoration site, aimed at the creation of a Building Information Model
 situation                   (BIM). The acquisition of photographs and historical materials is also
                             crucial for the creation of a database to support the Digital Twin
                             aimed at restoration.
                             The DTM is used to create a detailed plan and schedule for the res-
                             toration work, considering the various components of the building,
                             the extent of the damage and the available resources. The model is
 Planning and scheduling     also used to identify critical paths, optimise work sequences, and al-
                             locate resources more efficiently. This can help to reduce errors, re-
                             work, and waste, ultimately saving time and funds, and increasing
                             the overall quality and the cost/effectiveness of the results.
                             The DTM monitors the quality of the restoration work, ensuring con-
                             sistency with the design and specifications. The model also com-
                             pares the actual work to the planned work, identifying any deviations
 Quality control
                             or discrepancies that need to be addressed. This can help to reduce
                             errors, rework, and waste, ultimately saving time and funds, increas-
                             ing the overall quality and the cost/effectiveness of the results.



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Federico Cinquepalmi, Fabrizio Cumo - Using Digital Twin Models (DTM) for managing, protecting and restoring historical buildings



                                                                                                                                                                The DTM is used to document the restoration process, thus produc-
                                                                                                                                                                ing a detailed record of the work that has been done and the mate-
                                                                                                                                                                rials that have been used and providing the opportunity to cata-
                                                                                                                                     Track-change               logue the damaged assets, and to store all the information in a
                                                                                                                                                                database for tracking and preservation purposes. This can be use-
                                                                                                                                                                ful for future maintenance and restoration work, as well as for re-
                                                                                                                                                                search and education purposes.
                                                                                                                                                                With DTM it is possible to identify potential hazards and challenges,
                                                                                                                                                                allowing the construction team to plan and execute the restoration
                                                                                                                                                                work in state-of-the-art safety conditions. This will lead to a reduc-
                                                                                                                                     Safety and security ma-
                                                                                                                                                                tion of the accident and injury risks, ultimately improving the overall
                                                                                                                                     nagement
                                                                                                                                                                safety of the construction site. Moreover, Digital Twins are an effec-
                                                                                                                                                                tive method to reduce risks connected with vandalism, as they con-
                                                                                                                                                                tinuously monitor the security inside the site.
                                                                                                                                                                DTM facilitates communication and collaboration among the vari-
                                                                                                                                                                ous stakeholders involved in the restoration project. The model also
                                                                                                                                     Communication and col-
                                                                                                                                                                shares information and updates, tracking progress, and coordinat-
                                                                                                                                     laboration
                                                                                                                                                                ing the work of different teams and contractors. This can lead to a
                                                                                                                                                                reduction in the duration of the work, saving time and funds.
                                                                                                                                                                The DTM creates a virtual walkthrough of the building, allowing the
                                                                                                                                                                construction team to familiarise themselves with the building and
                                                                                                                                     Virtual walkthroughs       plan the restoration work more effectively. The model also identifies
                                                                                                                                                                potential hazards and challenges, such as difficult-to-reach areas
                                                                                                                                                                or structural weaknesses.



                                                                                                                                       3. Extensive application of the Digital Twin Models (DTM) to construction site
                                                                                                                                          management for heritage preservation

                                                                                                                                         The construction site management of Notre Dame and the Assisi Basilica differed
                                                                                                                                    in several ways due to the unique circumstances surrounding each restoration project.
                                                                                                                                    For Notre Dame, the use of Digital Twin technology was instrumental in facilitating the
                                                                                                                                    restoration process, allowing a very accurate mapping of the damage caused by the
                                                                                                                                    fire and helping in the development of a detailed plan for reconstruction.
                                                                                                                                         In addition, the DTM was used to manage the complex logistics of the construction
                                                                                                                                    site, including the movement of workers and materials, and to monitor the safety of the
                                                                                                                                    workers, as well as the detailed classification and registration of all historical damaged
                                                                                                                                    assets, during the restoration process. However, it is worth noting that the restoration
                                                                                                                                    of the Assisi Basilica did involve the use of advanced technologies such as laser scan-
                                                                                                                                    ning and 3D modelling to accurately document the existing structure and help in the
                                                                                                                                    restoration process. These technologies were used to create a 3D model of the basili-
                                                                                                                                    ca that allowed for accurate measurement and analysis of the damage caused by the
                                                                                                                                    earthquake [38].
                                                                                                                                         On the other hand, the restoration of the Assisi Basilica did not involve the use of
                                                                                                                                    Digital Twin technology from the initial phases. The restoration in Assisi was carried out
                                                                                                                                    through a combination of traditional building techniques and modern restoration meth-
                                                                                                                                    odologies. The restoration team relied on their expertise and experience to assess the
                                                                                                                                    damage to the basilica and to develop a restoration plan.
                                                                                                                                         In addition to restoration efforts, the Notre Dame Restoration Project also highlights the
                                                                                                                                    importance of preserving cultural heritage through digital means. By creating DTMs of the


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cathedral, experts were able to capture and preserve its unique characteristics and histor-
ical significance, even in the face of significant damage. Figure 7 shows a digital recon-
struction of the cathedral [39] made by the Centre National de la Recherche Scientifique
(CNRS), where the parts of the cathedral destroyed by fire are clearly marked in red.




                                                                                                     CONSERVATION SCIENCE IN CULTURAL HERITAGE


Figure 7. Notre Dame digital model realised by the French Centre National de la Recherche
Scientifique (CNRS) to manage the construction site of the cathedral restoration (© V. ABERGEL /
L. DE LUCA/MAP / Vassar College / GEA / Chantier scientifique Notre-Dame de Paris / Ministère
de la Culture / CNRS)» [39].



    3.1. Risk evaluation processes in the construction sites for restoration

    The fire that destroyed the Cathedral of Notre-Dame in Paris in 2019 also stresses a
very relevant issue related to safety management on construction sites, especially when
associated with restoration processes within historical buildings. Fire seems to be one of
the most common causes of damage for restoration construction sites, but there are also
other types of damage, both direct and indirect, which are a constant field of study for
safety experts, as well as insurance companies and forensic engineers [40].


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                                                                                                                                        Even if today, there is increased social awareness about heritage conservation and
Federico Cinquepalmi, Fabrizio Cumo - Using Digital Twin Models (DTM) for managing, protecting and restoring historical buildings



                                                                                                                                    reinforced legislation on the safety and security of construction sites in place through-
                                                                                                                                    out almost all of Europe, the kind of disasters like the fire of Notre Dame and many
                                                                                                                                    others, seem to prove that we are not yet at the point where the risks can be rightly
                                                                                                                                    balanced. The task of finding the right balance between opening a construction site
                                                                                                                                    within a cultural heritage site and the needs of preservation, often overlooking the
                                                                                                                                    equally dangerous extraordinary activities of maintenance, as well as simple interior
                                                                                                                                    renovations or temporary installations related to exhibitions, which are sometimes equal-
                                                                                                                                    ly dangerous in terms of temporary electrical equipment, as in the case of Notre Dame,
                                                                                                                                    is not an easy one.
                                                                                                                                        Almost everywhere in the world, governments are increasingly aware of the need
                                                                                                                                    to protect historical buildings where high vulnerabilities to fire are combined with the
                                                                                                                                    presence of inestimable works of art, but they sometimes underestimate the potential
                                                                                                                                    risk of all those transitional phases connected with temporary works within the build-
                                                                                                                                    ings, which often involve the temporary deactivation of full firefighting, or other security
                                                                                                                                    procedures or measures14.
                                                                                                                                        An impressive but not exhaustive list of disasters connected with the opening of
                                                                                                                                    construction sites related to restoration processes could be recalled as an example of
                                                                                                                                    the risk threatening any historical building during the mentioned delicate phase of in-
                                                                                                                                    tervention for conservation during the last decade of the twentieth century and the first
                                                                                                                                    decade of the twenty-first, as seen in Table 3.

                                                                                                                                    Table 3. Non-exhaustive list of the most prominent fire outbreaks in historical buildings during
                                                                                                                                    restoration processes (1989-2008) [40].

                                                                                                                                       Date                   Historical building                                Place

                                                                                                                                       1989      Palazzina di caccia di Stupinigi               Turin (Italy)

                                                                                                                                       1992      Windsor Castle                                 Windsor (UK)

                                                                                                                                       1996      Teatro La Fenice                               Venice (Italy)

                                                                                                                                       1997      Cappella della Sacra Sindone                   Turin (Italy)

                                                                                                                                       1998      Chiesa Santi Geremia e Lucia                   Venice (Italy)

                                                                                                                                       2003      Molino Stucky Isola della Giudecca             Venice (Italy)

                                                                                                                                       2006      Troitsky Cathedral                             Saint Petersburg (Russia)

                                                                                                                                       2008      Castello di Moncalieri                         Turin (Italy)


                                                                                                                                        All the buildings included in Table 3 are of great historical and artistic value for their
                                                                                                                                    respective countries and worldwide, often listed in the UNESCO world heritage site list,
                                                                                                                                    and therefore it is unthinkable that the restoration work could have been conceived
                                                                                                                                    without the utmost attention to safety aspects; yet whether the accident was accidental
                                                                                                                                    or intentional, a clear lack of attention to possible risk factors that were not initially
                                                                                                                                    taken into account, led, in all these cases, to serious damage to property and some-
                                                                                                                                    times also to individuals involved in procedures to extinguish the fire, not to mention
                                                                                                                                    the consequent effects, both in social and economic terms, from the loss of use of the
                                                                                                                                    property for several years. The frequency of those accidents involving Italian sites seems


                                                                                        436
related more to the very high concentration of historical and artistic assets in the coun-
try than to the lack of attention from Italian authorities towards the heritage in question,
which, on the contrary, is protected by very advanced laws and is a model for restoration
procedures globally. Research conducted by the National Observatory of the National
Fire Brigade Corps in collaboration with the IUAV University of Venice shows that the
risk of fire outbreak during restoration procedures seems to be sensibly higher than in
any construction site, and that incidents occur more often during lunchtime or between
the end of the working day and the beginning of the night surveillance shift [41]15.
     The application of digital procedures and techniques needs forward-thinking and
should begin ahead of the planning of a construction site for the restoration of historical
buildings, as was the case with Notre Dame, as it presents several advantages to be
considered broadly, such as the possibility of simulating the effects of the future con-
struction site on the building to be restored. A prior and accurate scanning of the build-
ing using the point-cloud methodology, in association with the creation of a Building
Information Model (BIM), therefore, seems to be a very valuable starting point for both
the restoration process, and in the event of an accident for possible reconstruction, as
in the case of Notre Dame. Only the in-depth knowledge of the building, thanks to a
very accurate preventive digital model, made it possible to proceed immediately with
the production of the stone and wood parts that will replace those destroyed by the fire
and, at the same time, clear the church of the debris produced by the fire, paving the
way for the complete implementation of a Digital Twin model of the construction site,
that will give back the cathedral to the Parisians before the end of 2025.


   4. Conclusions

    In conclusion, both the restoration projects for the Notre Dame Cathedral and the
Assisi Basilica have demonstrated the importance of utilising advanced digital technol-
ogies for the preservation, restoration and, ultimately, the management of historical




                                                                                                 CONSERVATION SCIENCE IN CULTURAL HERITAGE
buildings. The use of Digital Twin technology in the restoration of Notre Dame is pres-
ently providing a level of accuracy and precision that is hardly feasible with traditional
construction site techniques, allowing for a very efficient restoration process. On the
other hand, the restoration of the Assisi Basilica relied more on traditional building tech-
niques, mainly based on experience, but still utilising advanced technologies such as
laser scanning and 3D modelling to document the existing structure. The comparative
experiences of the two mentioned restoration projects, combining cutting-edge technol-
ogy with expert knowledge and careful planning, make it possible to restore and protect
these important cultural assets.
    The use of advanced technologies, including Digital Twins, has transformed the field
of historic preservation, allowing for a more comprehensive understanding of historical
buildings leading to more effective restoration and maintenance practices, as well as re-
search and studies connected to traditional masonry and timber construction techniques
and materials, further developing the historical knowledge of the construction processes.
    High-resolution scanning of buildings, using the point cloud technique, even before
the planning of a restoration site, appears to be an excellent preventive response to the
risks physiologically associated with the opening of a construction site, and their transla-
tion into a BIM, a perfect complement to the legal obligations on construction sites cur-
rently in force. However, it is the massive use of DTM that seems to be the real future
answer to the seemingly unpredictable risks arising from building heritage construction
sites, but which almost always turn out to be the causes of the worst disasters.


                                                                                               437
                                                                                                                                       Acknowledgements
Federico Cinquepalmi, Fabrizio Cumo - Using Digital Twin Models (DTM) for managing, protecting and restoring historical buildings




                                                                                                                                        The authors wish to thank the Centre National de la Recherche Scientifique (CNRS),
                                                                                                                                    France, for sharing the image related to the Notre Dame digital model realized for the
                                                                                                                                    digital construction site of the cathedral restoration. (© V. ABERGEL/L. DE LUCA/
                                                                                                                                    MAP/Vassar College/GEA/Chantier scientifique Notre-Dame de Paris/Ministère de la
                                                                                                                                    Culture/CNRS) [39]).


                                                                                                                                       Notes

                                                                                                                                       1
                                                                                                                                          According to the 1972 United Nations Convention Concerning the Protection of
                                                                                                                                    the World Cultural and Natural Heritage, Italy has one of the largest concentrations of
                                                                                                                                    historical and artistic patrimony in the World. As of 2021, Italy has 58 listed sites and
                                                                                                                                    31 sites in the tentative list, making it the state party of the convention with the most
                                                                                                                                    World Heritage Sites [42].
                                                                                                                                        2
                                                                                                                                          The 2016-2017 Central Italy earthquake sequence, defined by the Italian National
                                                                                                                                    Geo-Vulcanologic Institute (INGV) as the Amatrice-Norcia-Visso seismic sequence,
                                                                                                                                    began in August 2016. On 30 October 2016, the strongest tremor was recorded, at a
                                                                                                                                    magnitude of 6.5, with its epicentre between the municipalities of Norcia and Preci, in
                                                                                                                                    the province of Perugia. On 18 January 2017, a new sequence of four strong tremors
                                                                                                                                    of magnitude greater than 5 occurred, with a maximum of 5.5, and epicentres located
                                                                                                                                    between the L’Aquila municipalities of Montereale, Capitignano and Cagnano Amiter-
                                                                                                                                    no. This set of events caused a total of about 41,000 displaced persons, 388 injured
                                                                                                                                    and 303 dead, of whom 4 died indirectly, as well as incalculable damage to the region’s
                                                                                                                                    built-heritage and the complete destruction of the historical centre of the village of Am-
                                                                                                                                    atrice. The total estimated damage amounts to 26.5 billion euros, Amatrice being the
                                                                                                                                    most damaged municipality with over 1.3 billion euros in damages, followed by Came-
                                                                                                                                    rino with 1.2 billion euros, and by Norcia, with 1.1 billion euros [43].
                                                                                                                                        3
                                                                                                                                           On 12 November 2019, an exceptional high tide wave occurred in the northern
                                                                                                                                    Adriatic Sea also affecting Venice and its lagoon. Although an exceptional high tide
                                                                                                                                    (>140 cm) had been predicted by the numerical models in use, during the course of the
                                                                                                                                    evening, sudden gusts of wind at over 100 km/hr caused a further local intensification
                                                                                                                                    of this phenomenon. The maximum level of 187 cm resulting from those concomitant
                                                                                                                                    circumstances was recorded at Venice – Punta della Salute and occurred at 22:50 with
                                                                                                                                    a delay of about one hour after the peak of 182 cm, recorded in the open sea by the
                                                                                                                                    Acqua Alta Platform causing the complete flooding of the entire historic centre with
                                                                                                                                    enormous damage to people and properties. The historical city of Venice has been
                                                                                                                                    protected under the UNESCO World Heritage Convention since 1987, and after the
                                                                                                                                    almost two-metre-high tide flood occurred in 2019, a continuous monitoring of the city
                                                                                                                                    by the EU Copernicus satellite programme has been in place, also considering the
                                                                                                                                    recurrence of the phenomenon.
                                                                                                                                        4
                                                                                                                                          In Amatrice, the facade of the Church of San Francesco, dating back to the four-
                                                                                                                                    teenth century, has collapsed, and has also lost its oculus. There was also a great deal
                                                                                                                                    of damage to the Church of Sant’Agostino near the ancient walls of Amatrice, with its
                                                                                                                                    typical Gothic portal, and the “Cola Filotesio Civic Museum”. The ancient gates of Accu-
                                                                                                                                    moli, dating back to the first decades of the year 1000, have been devastated. The dam-
                                                                                                                                    age involved the medieval walls and gates, remains of the bastions, medieval churches
                                                                                                                                    and palaces, and some Baroque ornaments. In Arquata del Tronto, one of the rare point-


                                                                                        438
ed-arch doors dating back to the 1600s was damaged. Camerino was the most affected
city which saw the collapse of one of the Santa Chiara monastery walls and some dam-
age to the cathedral clock. In Tolentino, the church of Santissimo Crocifisso ai Cappuc-
cini, formerly known as the Church of Peace, collapsed. In San Ginesio, the convent of
San Francesco, the convent of the Benedictine Sisters and the Collegiate Church are
unusable. Also, in Macerata there was damage to the Galleria delle Fonti and the façade
of the Church of San Giovanni. Furthermore, some cracks have also appeared inside the
building that houses the Mozzi Borgetti Library. The monuments of Norcia, in the prov-
ince of Perugia, suffered significant damage, such as the Church of San Benedetto and
the Benedictine walls. Small cracks were reported on the outside of the Cathedral of
Urbino, which had already undergone restoration following the 1997 earthquake.
     5
       The creation at the University of Udine, in Italy, of the UNESCO Chair for Intersec-
toral safety for disaster risk reduction and resilience is a significant scientific response to
the natural disasters that have occurred in Italy since 2016 and represents a world-class
centre of excellence on issues related to security, disaster risk reduction and resilience.
     6
       Article 1 of Law no. 229 of 15 December 2016, “Conversion into law, with amend-
ments, of Decree Law no. 189 of 17 October 2016 – Urgent interventions in favour of
the populations affected by the earthquake of 24 August 2016” extended tax exemp-
tions for supporting cultural activities in Italy (the so called Art Bonus) to donations in
favour of the Ministry of Culture (MIC), for maintenance, protection and restoration in-
terventions also of cultural assets of religious interest (entities and institutions of the
Catholic Church or other professions) present in the municipalities affected by earth-
quake events since 2016. The interventions on built heritage are co-financed by the
Commissioner of the Government for the 2016 earthquake reconstruction.
     7
       The most relevant technologies used to monitor and assess damage in historical
buildings can use remote or local observations to achieve their goal. Some of them are
installed onboard autonomous robots of different types such as UAVs (Unmanned
Aerial Vehicle), rovers and submarines. Other tools are used to inspect the sites from




                                                                                                    CONSERVATION SCIENCE IN CULTURAL HERITAGE
space, such as earth observation satellites, or from high altitudes, as in aerial surveys,
or they are placed on fixed or mobile sensors, as is the case for environmental sen-
sors, Radio-Frequency Identification (RFId) beacons and distance sensors. Moreover,
the monitoring devices can analyse single or multiple physical properties at the same
time. One example is the environmental sensors that can monitor temperature, pollut-
ants and humidity, at the same time or multispectral/hyperspectral cameras that can be
used to inspect the pollutants and moulds on surfaces and measure surface tempera-
tures, as well as radar sensors to inspect heights and displacements. There is quite a
high number of possible technologies available, and they should be adopted specifical-
ly for any site, taking into account what the focus of the monitoring action is, in addition
to the sensors’ location and the category of the site.
     8
       The Copernicus Emergency Management Service supports actors dealing with
natural disasters, man-made emergency situations, and humanitarian crises as well as
those involved in preparedness and recovery activities. The service improves people’s
safety and helps to prevent loss of lives and/or property before, during, and after disas-
ters by providing information, for example, on the type and magnitude of risks, the
extent of a flooded area, the spread of a forest fire, the damage caused by an earth-
quake or the progress of recovery and reconstruction efforts (European Commission:
Emergency management Service, service overview).
     9
       Starting in August 2016, a sequence of strong earthquakes struck Central Italy,
causing several casualties among the local population: over 300 people were killed,


                                                                                                  439
                                                                                                                                    360 injured and over 2000 were left homeless. During the long seismic sequence,
Federico Cinquepalmi, Fabrizio Cumo - Using Digital Twin Models (DTM) for managing, protecting and restoring historical buildings



                                                                                                                                    Italian Civil Protection authorities asked for the activation of the Copernicus Emergen-
                                                                                                                                    cy Management service, which produced about 120 maps of the affected zones, with
                                                                                                                                    the aim of supporting the national authorities’ decisions in the activities of rescuing
                                                                                                                                    populations and securing as much as possible of the built environment, infrastructures
                                                                                                                                    and cultural heritage. (Released date: Mer, 02/11/2016 - 13:00 Copyright: Copernicus
                                                                                                                                    EU Programme ® EU Commission, 2016)
                                                                                                                                         10
                                                                                                                                            The Digital Twin model was used to aid in the restoration and conservation efforts
                                                                                                                                    for the basilica. For example, it was used to develop a detailed map of the building’s
                                                                                                                                    surface cracks, which are a major concern for the building’s stability. This information
                                                                                                                                    can be used to develop targeted restoration plans that address specific areas of con-
                                                                                                                                    cern, rather than adopting a more generalised approach.
                                                                                                                                         11
                                                                                                                                            The complex timber structure supporting the lead roof tiles of Notre Dame cathe-
                                                                                                                                    dral was technically well described by Eugene Viollet Le Duc (1814-1879) who was
                                                                                                                                    entrusted by the French government with the Cathedral’s restoration, which involved
                                                                                                                                    the entire timber architecture supporting the gothic roof and the reconstruction of a
                                                                                                                                    wooden Gothic spire at the transept intersection, rebuilt employing the same carpentry
                                                                                                                                    techniques as those employed in the Middle Ages.
                                                                                                                                         12
                                                                                                                                            Despite the significant damage caused by the fire, many of the cathedral’s most
                                                                                                                                    precious artefacts and works of art were saved, thanks in part to the heroic efforts of
                                                                                                                                    firefighters and other emergency responders. The fire also spurred an outpouring of
                                                                                                                                    support from around the world, as people donated money and resources to help with
                                                                                                                                    the restoration and rebuilding of this iconic symbol of French history and culture.
                                                                                                                                         13
                                                                                                                                            The Notre Dame fire started in the attic, above the gothic stone arches of the
                                                                                                                                    cathedral vaults. The current hypothesis is that the fire may have been caused by
                                                                                                                                    short-circuited cables from the six electronic bells installed in the spire, which were
                                                                                                                                    intended to be temporarily operating during the original construction site. The fire
                                                                                                                                    spread through most of the wooden carpentry supporting the lead roof (the so called
                                                                                                                                    “forest”) reaching the cathedral’s 300-foot wooden spire. Several parts of the gothic
                                                                                                                                    arches collapsed, and some of the upper walls of the cathedral were also damaged.
                                                                                                                                    However, the vaulted stone ceiling of the cathedral prevented extensive damage. Ac-
                                                                                                                                    cording to authorities, a nine-hour battle against the fire was necessary to extinguish it.
                                                                                                                                    The fire started at around 6:50 p.m. on Monday, April 15, 2019, and was finally extin-
                                                                                                                                    guished by early Tuesday morning.
                                                                                                                                         14
                                                                                                                                            The topic of the preservation of historical buildings and fire safety in restoration
                                                                                                                                    work was dealt with in Siena at a major international congress in 2008, and more recent-
                                                                                                                                    ly in Bergamo during Safety Expo 2016, in Turin at PREVINTO 2018 and at many other
                                                                                                                                    conferences. Despite this, fire safety on restoration sites is still not greatly discussed and
                                                                                                                                    therefore not properly implemented by those responsible for such activities [39].
                                                                                                                                         15
                                                                                                                                            The construction site for restoration procedures seems to be among the primary
                                                                                                                                    causes of fires in listed buildings together with short circuits in electrical systems and
                                                                                                                                    vandalism. Research conducted by the engineer, Stefano Zanut of the National Obser-
                                                                                                                                    vatory of the National Fire Brigade Corps and Prof. Piero Michieletto of the IUAV Uni-
                                                                                                                                    versity of Venice, shows that the working conditions in a restoration site are more in-
                                                                                                                                    sidious than those in an ordinary building site: in the city of Venice, where new
                                                                                                                                    constructions are not allowed and, only the reuse and conservation of existing build-
                                                                                                                                    ings is permitted, fires were found to be six times more frequent than in building sites
                                                                                                                                    in the nearby region of Friuli (12% compared to 1.8%). Most fires within construction
                                                                                                                                    sites occur in the time slots between 12.00 a.m. and 1.00 p.m. and between 5.00 p.m.


                                                                               440
and 7.00 p.m., i.e. in the absence of workers and before the start of post-work surveil-
lance. The analysis of the causes makes us reflect on the importance of the manage-
ment aspect as an indispensable support for the safety of cultural property [40].


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   Biographical notes

    Federico Cinquepalmi (PhD) holds a Master degree in Architecture from the IUAV
University of Venice, Italy and a PhD in Science and Technology for Industrial innova-
tion from the Sapienza University of Rome, Italy. Since March 2022 is a full professor
of Project Management at the faculty of Architecture of the Sapienza University. From
2009-2022 he was senior researcher at the Italian National Agency for New Technolo-
gies, Energy and Sustainable Economic Development (ENEA) and also at the Italian
National Agency for Environmental Protection and Research (ISPRA). In the mean-
time, he was appointed Director for international affairs at the Ministry of Universities


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                                                                                                                                    and Research, Italy. In the last 30 years he has focused his scientific research in the
Federico Cinquepalmi, Fabrizio Cumo - Using Digital Twin Models (DTM) for managing, protecting and restoring historical buildings



                                                                                                                                    sectors of sustainable development and policies applied to built environments, digital
                                                                                                                                    technologies for building management, and cultural heritage.

                                                                                                                                        Fabrizio Cumo holds a Master Degree in Engineering and a PhD in Science and
                                                                                                                                    Technology for Industrial innovation from the Sapienza University of Rome (Italy).
                                                                                                                                    Since 2007 he has been a professor in Applied Technical Physics at University of
                                                                                                                                    Rome. Since 2015, he has been president and coordinator of the Graduate Course in
                                                                                                                                    Building Process Management - Project Management at the Faculty of Architecture
                                                                                                                                    (Sapienza). From 2015-2021, he was the Director of the Master in Building Information
                                                                                                                                    Modelling at the same Faculty. Since 2021, he has been Director of the Master in Con-
                                                                                                                                    struction, Digital Twin & Artificial Intelligence. From 2016-2022 he was Director of the
                                                                                                                                    Interdepartmental Center for Territory Building Restoration and Environment. (CITERA).
                                                                                                                                    He is the Scientific Officer of several national and international research projects and the
                                                                                                                                    author of more than 150 publications.


                                                                                                                                       Summary

                                                                                                                                         Historical buildings are essential cultural assets to be preserved and maintained for
                                                                                                                                    the sake of future generations. However, they are also highly vulnerable to natural di-
                                                                                                                                    sasters and other extreme events, which can cause irreparable damage or even their
                                                                                                                                    total loss. To manage these risks, a growing number of experts are turning to Digital
                                                                                                                                    Twin Models (DTM), conceived as more than a mere virtual replica of physical objects
                                                                                                                                    or systems. They can be used to monitor, inspect, and simulate the functioning and
                                                                                                                                    behaviour of a building in real-world scenarios. In the context of reconstruction, DTM
                                                                                                                                    can be used to create virtual models of damaged buildings, allowing experts to assess
                                                                                                                                    the extent of the damage and plan restoration.
                                                                                                                                         By creating a DTM of a historical building, experts can gain valuable insights into its
                                                                                                                                    construction technique, structural integrity, maintenance needs, and potential vulnerabil-
                                                                                                                                    ities in real time. This can help to extend the lifespan of the historical building and ensure
                                                                                                                                    that it remains in good condition for future generations. In case of an extreme event, such
                                                                                                                                    as a natural disaster or terrorist attack, war or vandalism, a DTM, together with all related
                                                                                                                                    enabling digital technologies, can be used to plan for and respond to the crisis, also
                                                                                                                                    simulating the effects of a disaster to develop emergency response plans accordingly.
                                                                                                                                    Therefore, the use of DTM can enhance the current vision of a historical building thus
                                                                                                                                    helping it to increase its resiliency to potential damaging, preserving, and maintaining its
                                                                                                                                    historical and cultural value and characteristics through time.


                                                                                                                                       Riassunto

                                                                                                                                        Gli edifici storici sono beni culturali essenziali da mantenere e preservare per il bene
                                                                                                                                    delle generazioni future. Tuttavia, data la loro natura, sono anche molto vulnerabili alle
                                                                                                                                    calamità naturali e ad altri eventi estremi, che possono causare danni irreparabili o
                                                                                                                                    addirittura la loro distruzione. Per gestire questi rischi, un numero di esperti sempre
                                                                                                                                    maggiore si rivolge ai Digital Twin Models (DTM), in grado di andare oltre ad una sem-
                                                                                                                                    plice replica virtuale di oggetti o sistemi fisici. Questa tecnologia può infatti essere uti-
                                                                                                                                    lizzata per monitorare, gestire e simulare il funzionamento interno ed il comportamento


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di un edificio posto nell’ambito di scenari reali. Nel contesto di processi di ricostruzio-
ne, il DTM può essere utilizzato per creare modelli virtuali di edifici danneggiati, con-
sentendo agli esperti di valutare l’entità del danno e pianificarne il ripristino.
     Creando il DTM di un edificio storico, gli esperti possono ottenere preziose infor-
mazioni sulla sua tecnica di costruzione, sulla sua integrità strutturale, e sulle sue
esigenze di manutenzione e potenziali vulnerabilità, il tutto in tempo reale. Ciò può aiu-
tare a prolungare la vita degli edifici storici ed a garantire che restino in buone condi-
zioni il più a lungo possibile. In caso di eventi estremi, come disastri naturali o attacchi
terroristici, guerra, incidenti di cantiere e vandalismo, un DTM insieme a tutte le tec-
nologie digitali abilitanti correlate, può essere utilizzato per pianificare e rispondere alle
crisi, simulando anche preventivamente gli effetti di un disastro, permettendo lo svilup-
po di piani di risposta alle emergenze. Pertanto, l’uso del DTM può migliorare la nostra
visione attuale di un edificio storico consentendo di aumentarne la resilienza ai danneg-
giamenti, preservando e mantenendo il suo valore storico e culturale e le sue caratte-
ristiche nel tempo.




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