Considerazioni sull’interoperabilità tra modelli BIM e l’analisi strutturale degli edifici storici

L’introduzione a larga scala di nuove tecnologie come il “Terrestrial Laser Scanner” (TLS) e tecniche di fotogrammetria digitale hanno reso possibile la documentazione veloce ed efficiente della geometria degli edifici esistenti, anche particolarmente complessi, dando l’opportunità di creare modelli tridimensionali molto dettagliati. La grande quantità di dati che ne deriva, può e deve essere sfruttata all’interno della nuova tecnologia BIM per creare il modello dell’edificio, capace di includere diversi livelli di studio: architettonico, strutturale, gestionale, etc. In questo studio sono riportate alcune considerazioni sulla tecnologia BIM finalizzate alla creazione di un modello contenente diversi tipi d’informazione e correttamente esportabili in software specializzati nell’analisi strutturale. Sembra ovvio poter affermare che un modello strutturale accurato, anche se semplificato,debba rappresentare correttamente l'edificio da analizzare e deve predire meccanismi di collasso realistici. Il dispendio di risorse necessario a ricreare il modello geometrico per tali analisi dovrebbe oggi essere superato dalle possibilità offerte dalla tecnologia BIM di fornire già il modello geometrico opportunamente esportato nei formati necessari ai software di calcolo. Tale opportunità è ancora più importante quanto più è complesso l’edificio da analizzare, come il caso del patrimonio storico-architettonico esistente. Per verificare questa delicata fase di passaggio da una tecnologia BIM ad uno strumento di analisi strutturale, che può definirsi come una verifica di interoperabilità, Autodesk Revit è stato scelto per esplorare le possibilità del modello BIM, invece per l’analisi strutturale sono stati provati due software noti come CSI SAP2000 v16.0 e Simulia Abaqus 6.11. Sono stati creati due modelli geometrici semplici che rappresentano due tipologie molto diffuse di edifici storici: una schiera costituita da tre unità strutturali semplici, a due piani con aperture sui due lati, e una chiesa con pilastri isolati e abside circolare. I formati di esportazione verificati sono .IFC, ACIS (.sat) e .ERX. Si riportano qui alcune considerazioni,descrivendo le difficoltà e le limitazioni del procedimento che ognuno di questi formati fornisce. Infine si riporta un caso di studio reale, dove la procedura dalla tecnologia BIM all’analisi strutturale è potuta avvenire con successo, dimostrando che, con le dovute attenzioni, è possibile usare il modello BIM per le verifiche strutturali su edifici storici, permettendo di ricorrere anche alle verifiche più complesse come quelle non lineari

Seismic assessment of historical masonry structures: The former Italian Embassy

Preservation of architectural heritage placed in seismic regions is an important issue. This has emerged also from the requirements of the Eurocodes that are going to replace the current design code KTP-89. This paper investigates the structural behaviour of an existing masonry building (former Italian embassy; nowadays a monument of the second category) built in the 1930s in Tirana by means of finite element analysis. Preservation and rehabilitation of the building can be successfully achieved after a proper analysis of the structure. The static analysis of historical masonry building does not show problems to withstand vertical loads, thus attention is given to the seismic analysis. This is performed by static nonlinear procedure (pushover analysis). Building a reliable three-dimensional finite element model of the building is essential for the accuracy of the analysis results. The model assumes that the masonry structure is homogeneous and the material behaviour is nonlinear. The masonry material strength is based in laboratory tests performed on specimens extracted from the building. The geometry of the building was based on a 2007 architectural survey and on the original plans of the 1930s. The results of the finite element model will help to predict the local and global collapse mechanisms and assess the security based on the map of seismic risk in order to help in the identification of a proper retrofitting strategy

Rapid assessment of seismic vulnerability of historic masonry structures through fragility curves approach and national database data

The research focuses on shared built heritage, which forms one of the most vulnerable parts of the building stock in historic centres. To prevent severe damage to this building category and to aid decision-making, the paper presents a rapid seismic vulnerability assessment procedure based on an engineering approach to safety assessment. The construction of fragility curves is developed on a probabilistic framework on the computed set of Safety Factors over a range of considered Peak-Ground-Accelerations. Input data necessary for the computations are extracted from CARTIS database. The methodology is implemented in a spreadsheet combined with a script in Visual Basic for Applications. Two case studies are used to demonstrate the applicability to a single building and at the territorial scale. Results show that the proposed methodology allows for a rapid testing of loss of structural performance given various scenarios, as well as contributing by prioritizing interventions in probabilistic terms

Simplified seismic vulnerability analysis of historic residential buildings with fragility curves

In the disciplines dealing with the preservation of the built heritage, the assessment of the seismic vulnerability plays a decisive role. A high number of numerical models have been developed to simulate the behaviour of different building typologies subjected to seismic action, but requiring a in-depth knowledge of the object of study they are not suitable for urban scale analysis. The widespread historical built heritage in Italy, as in many other countries, requires the definition of rapid and reliable assessment procedures that allows a large-scale evaluation of the vulnerability of historical buildings before a seismic event. This analysis should be based on existing databases, such as the Reluis-Cartis database, without necessarily proceeding at this stage with detailed investigations of each individual building. Based on state-of-the-art procedures, a methodology is proposed for the fast construction of the fragility curves starting from information available on the Reluis-Cartis database. The curves define the relationship between the probability of reaching a safety factor or a vulnerability index in function of the seismic acceleration PGA. The methodology allows to understand the probability of loss of the structural safety in function of a given PGA. The developed methodology is applied here in two cases: (a) a small historic building hit by several earthquakes in order to calibrate the methodology and (b) to a set of historic building of the same typology in a historic center never hit by earthquakes in order to assess the level of the probability of loss of the structural safety given the code defined PGA, as well as to draw conclusions on prioritizing intervention strategies at the urban scale

Advances in Cultural Heritage Studies : Year 2020 : Contributions of the European Students’ Association for Cultural Heritage

The announcement of the creation of a European Year of Cultural Heritage (year 2018) – by the Decision 2017/864 of the European Parliament – encouraged the creation, in 2017, of the European Students’ Association for Cultural Heritage (ESACH). ESACH has become the first still-growing interdisciplinary and cross- -generational network in the field. Currently brings together young researchers and researchers at early stages of their careers, in the fields of culture and heritage, from all kinds of academic disciplines and is made up of members from various European universities and research centres (see www.esach.org). Within the network, the main questions are: How do we engage with the past elements of our culture(s)? How and why do we protect culture as a genuine element of a contemporary cultural system? What do younger generations state as heritage and what ways do they see to safeguard and experience it? ESACH stands up for a participatory way of involvement and is eager to take part in the cultural discourse at European and national levels. Since ESACHS’ foundation, the Portuguese publisher Mazu Press (www.mazupress.com) has been associated with the initiatives of the Portuguese branch of ESACH based in Lisbon (Sharing Heritage Lisbon), firstly with the promotion actions and then with the publication of the book “New Perspectives in Interdisciplinary Cultural Heritage Studies. Contributions of the European Students’ Association for Cultural Heritage in the European Year of Cultural Heritage 2018”. In this atypical Covid-19 pandemic year, Mazu Press again invited ESACH to join the renewed idea of “unifying through Cultural Heritage”, creating the opportunity for all to associate their efforts to this volume of “Advances in Cultural Heritage Studies, Year 2020”. Until now, ESACH members have been given the opportunity to contribute their ideas in several European events organized by the respective stakeholders, such as the Genoa Meeting, in October 2019, which had the cultural, logistic and financial support of the University of Genoa and foremost the PhD Course in Study and Enhancement of the Historical, Artistic-Architectural and Environmental Heritage. This book brings together twenty chapters by twenty four authors from Canada, Greece, Ireland, Italy, Poland, Portugal, Slovakia, Spain and Turkey. This sharing of knowledge, culture and heritage studies, through various disciplines, shows the richness – advances and new perspectives – generated by the common passion for cultural heritage.Mazutech R&D; Università di Genova / Scuola di Scienze Umanistiche / Dottorato in Studio e Valorizzazione del Patrimonio Storico, Artistico-Architettonico e Ambientaleinfo:eu-repo/semantics/publishedVersio

Seismic Vulnerability Assessment of Historic Masonry Buildings through Fragility Curves Approach

The assessment of the seismic vulnerability of built heritage is still an open issue. Regarding this topic, in recent years many researchers have worked in the development of refined numerical models to simulate the behaviour of different building typologies subjected to seismic action. To be reliable, these models require in-depth knowledge of the building object of study. In many countries, such as Italy, where the widespread historical heritage is widely present, there is the need to define quick, but reliable, evaluation procedures, which allow, in advance, to assess the vulnerability of the historical heritage of an entire area using databases already present without necessarily proceeding with detailed investigations on each building. Based on procedures in the literature, the authors have developed an assessment methodology focused on the construction of fragility curves, safety factor vs PGA and vulnerability index, which allows to formulate hypotheses on the probable behaviour of a specific type of building, to any similar actions and the probable expected damage. In the view of evaluating the seismic safety of a small historic centre in an area with a high seismic propensity, this procedure could be useful for prioritizing interventions in probabilistic terms

Challenges from building information modeling to finite element analysis of existing buildings

The use of Terrestrial Laser Scanning (TLS), Digital Photogrammetry, powerful computers and advanced software has made possible the creation of complex and complete 3D models of buildings. Today much of the research is focused in the multidisciplinary use of this big amount of data. This paper presents the considerations that were made during the research for integration of building information modelling and some of the main finite element analysis software for creating a structural model through different exporting formats. Furthermore, it compares and evaluates the effectiveness of different export formats within the interoperability with some of main finite element software.A proposal is made in order to use the BIM for the documentation of the crack pattern in the existing buildings and to develop a procedure to export these cracks in the automatically generated structural model. The study also considers the difficulties during the implementation of the procedures in BIM and the future possibilities of this technology

BUILDING INFORMATION MODELLING APPLIED TO BUILT HERITAGE: A STRUCTURAL ANALYSIS PERSPECTIVE BASED ON THE INTEROPERABILITY

Cultural heritage has become a topic of great interest in the recent years. The widespread of building information modelling (BIM) technology for the design of new buildings, has raised the attention of many researchers to explore the possibilities of BIM for the design and the documentation of built heritage in the restoration process. The use of Terrestrial Laser Scanner (TLS) and Digital Photogrammetry, powerful computers and many advanced software has made possible the creation of complex and complete 3D models of buildings. Today much of the research is focused in the multidisciplinary use of this big amount of data. This paper presents the considerations that were made during the research for integration of building information modelling and some of the main finite element analysis software in creating a calculation model through different exporting formats. A proposal is made in order to use the BIM for the documentation of the crack pattern in the existing buildings and to develop a procedure to export these cracks in the automatically generated calculation model. The paper also explores the methods used for the implementation of BIM in cultural heritage and further compares and evaluates the effectiveness of different export formats within the interoperability with some of main finite element software. The study also considers the difficulties and obstacles during the implementation of the procedures in BIM and the future possibilities of this technology

Development of the simulation model for Digital Twin applications in historical masonry buildings: The integration between numerical and experimental reality

The structural system integrity in historical masonry buildings is studied by developing the concept of the Digital Twin. The objectives are to develop a procedure for creating an accurate digital model, which integrates the experimental physical reality and to use it to study the structural response of the system, its preventive maintenance and strengthening operations. The key elements examined are the building of an accurate three-dimensional geometric model, the choice of material properties and, the consideration of construction stages along the history. The relation to structural surveys, in situ observation and measurements is explored, with particular attention to reproducing the damage observed. Non-Linear Finite Element modelling is adopted. The structural system is generated in a semi-automatic way, reducing time-consuming modelling tasks and reaching a good approximation of real geometry as well as having an efficient discretization in a finite element model. This procedure can be used to assess with high precision the present structural conditions of the system, study its future evolution for preventive maintenance or practical interventions as well as to understand past documented failures of structural members of the building. An application considered in Milan Cathedral demonstrates the applicability and advantages of the proposed procedure in complex buildings