Abstract
This chapter presents a process for the study of an architectural and archaeological heritage. It is an interdisciplinary work carried on with the integration of different digital systems for surveying and managing data. An innovative methodological approach is presented, based on the HBIM for 3D digital management of data, related to the analysis of masonry techniques, of conservation and damage, paying particular attention to the masonries 3D stratigraphic study. A specific focus is on the use of HBIM to design the restoration yard. The case study is the church of San Cipriano, located near the small country of Castelvecchio Calvisio in the province of L'Aquila (Italy).
TopIntroduction
The following evaluations described in this paper aim to assess the most frequently used digital technologies for the analysis and use of architectural heritage, starting from a necessary methodological premise to focus on a specific case study, often used as a test bed for the technologies and procedures developed in various research projects.
In fact, the experiment has its origins in a research project carried out by CNR-ITC on a number of churches in the historic Baronia di Carapelle area and articulated by means of an investigation into the vulnerability and seismic damage of the churches in the sample, carried out in 2008, and a successive research project carried out after the earthquake that struck the Aquila region in 2009, which attempted to evaluate the accuracy of the previous methodological approach and the reliability of the results deriving from the use of the damage assessment and seismic vulnerability guidelines.
Following the updates to the research project, a multi-disciplinary team, composed of researchers from ITC and scholars from the Aquila University, decided to investigate one of the case studies analysed in that specific context, to enrich the already consolidated methodology for the rapid individualisation of vulnerabilities and seismic damage through the creation of a three-dimensional photogrammetric image of the heritage property and its state of conservation.
The new method proposed was aimed at obtaining, by means of the processing of a set of digital images using software based on the Structure from Motion (SfM) algorithm, a series of three-dimensional digital models, useful for revealing the state of the site and the historical evolutions, using a method of immediate visualisation and to conduct a stratigraphic reading of the building directly on the three-dimensional model. Said procedure allows for an immediate evaluation of the relationship between the various USM and to increase the accuracy of the interpretation of the individual units and the different construction stages of the entire building, avoiding the need to compare the photomaps and detect each individual parameter. This procedure was flanked by the construction of a parametric model of the building, used both to simulate the interference caused by any eventual restoration works and as the basis for the stratigraphic analysis of the wall parameters of the church.
The seismic events of 2016 represented a new opportunity to expand the team and broaden the knowledge of the building in question even further, through the actuation of a laser scanning survey and a new verification of all the material produced on the site over the years, which is currently a condemned building. The evaluations on the specific case study described in the following paper, represents a further contribution to developing a method for acquiring a more thorough understanding of the state of the cultural heritage site that is as shareable as possible. In fact, the constant refinement of the methodological instruments, the use of photo modelling and laser scanning techniques and technologies, as well as georeferencing and representational models can allow for the representation and exchange of a more complete and integrated knowledge of the cultural asset. Knowledge which, when applied to the territorial context of the heritage site, with its anthropic, natural characteristics and the potential risks of the latter, can ensure the finalisation of a broadly shared understanding of how to safeguard the cultural heritage site, through the opportune and well-researched creation of a concrete territorial and architectural information system. 1
Figure 1. Photos of the church of San Cipriano
Key Terms in this Chapter
Cultural Heritage: UNESCO defines “Cultural Heritage” as “the legacy of physical artifacts and intangible attributes of a group or society that are inherited from past generations, maintained in the present and bestowed for the benefit of future generations”.
Architectural Heritage: The UNESCO 1972 World Heritage Convention , indicates as cultural heritage monuments, group of buildings and sites, outstanding universal value from the point of view of history, art or science. In the modern theory by Brandi, the qualities of a cultural heritage are the historical and the aesthetic values. An historical building is a complex system of spaces, volumes, materials, surfaces, constructive aspects, actual and past functions and configurations, degradation, etc. The whole is the result of a continuous historical process of modification and transformation. An architectural heritage can be interpreted as an “artifact”, where its elements are witnesses of the cultures, actors, and of events occurred during the life of the building. In the study of architectural heritage is fundamental the archival analysis.
Archaeology of the Architecture: Research line that apply the stratigraphic method, typical of archeology, to the historical building and its wall elevation to reconstruct its history. The discipline is directly involved in the problems of conservation and restoration of the architectural heritage, as the investigations underline the complexity and the abundance of information of the architectural artifact and, consequently, the responsibility of those who intervene to preserve or transform it.
Tangible Heritage: UNESCO says that it “includes buildings and historic places, monuments, artifacts, etc., which are considered worthy of preservation for the future. These include objects significant to the archaeology, architecture, science or technology of a specific culture. Objects are important to the study of human history because they provide a concrete basis for ideas, and can validate them. Their preservation demonstrates recognition of the necessity of the past and of the things that tell its story. Preserved objects also validate memories; and the actuality of the object, as opposed to a reproduction or surrogate, draws people in and gives them a literal way of touching the past. This unfortunately poses a danger as places and things are damaged by the hands of tourists, the light required to display them, and other risks of making an object known and available”.
Architectural Survey: Process of understanding of building’s characteristics and their appropriate graphical and visual documentation, through the analysis, selection, synthesis and representation of the architectural characteristics. Traditionally, the surveying is characterized by the succession of the following steps: a preliminary study and acquisition of documents; the surveying design; the measurement; the restitution with models for the interpretation and presentation of architectural heritage. Only the measurement phase is “objective”, while the others are “subjective” because influenced by the skills, culture and experience of the surveyor. Advanced digital tools, such as laser-scanners and digital photogrammetry, partially inverted the process, anticipating the measurement phase.
Stratigraphic Units of the Walls (USM): They are the result of individual actions, construction processes (positive units) and removal (negative units) that characterize a building. They contain a lot of information, both material and cultural, that allow us to understand the technological knowledge, economics and ideologies. The direct relations, of anteriority and posteriority between single USM, allow to reconstruct the history of the building.
Digital Heritage: The Charter on the Preservation of the Digital Heritage published by UNESCO in 2003 indicates the “Digital Heritage” as “Common Heritage”, made by: “cultural, educational, scientific and administrative resources, as well as technical, medical and other kinds of information created digitally, or converted into digital form from existing analogue resources. It includes different kinds of products such as texts, databases, images, audio, graphies, software and web pages”.
Management (of Heritage): The UNESCO Resource Manual Managing Cultural World Heritage (2013) AU21: The in-text citation "World Heritage (2013)" is not in the reference list. Please correct the citation, add the reference to the list, or delete the citation. defines management as a system, made by a “series of processes which together deliver a set of results, some of which feed back into the system to create an upward spiral of continuous improvement of the system, its actions and its achievements” (p.25). These systems are local and regional, related to culture and tradition. The Manual underlines that management is based on Planning, Implementation, and Monitoring, and the main outcomes are: The promotion of cultural diversity; The protection of natural environment (particular ecosystems in and around sites); The protection of tangible assets within properties (communities, cultures and knowledge); The providing of vitality to communities; The allowing of compatible land uses and economic activities (p.23). Fundamental is the role of stakeholders, their consensus and their understanding of values.
Stratigraphic Analysis: Method that allows to identify the units that make up the context (architectural complexes, constituent elements, elevation walls, etc.) and the single masonry units (USM) with the aim of reconstructing a physical sequence based on relationships of anteriority, posteriority and contemporaneity. This allows to obtain a relative chronology that can be transformed into “absolute” thanks to the dating of the single USM with the “guide fossils”: chronological indicators such as the classification of masonry techniques or the chronological typology of architectural openings.
Sustainability: It aims to match the needs of the present with the future ones, without compromising the ability of future generations to meet their needs. Sustainability in conservation means strategies and actions finalized to conserve heritage according to a sustainable development. Usually, it aims to relate conservation to politics of development, i.e. to economy.
3-D Modeling: Realization of a model in the virtual 3-D space, made by digital solids and/or surfaces, able to simulate the characteristics of an object. The 3D model can be based or include photographic images, often taken from reality. The final effect of simulation can derive from both 3-D shapes and texture mapping. The 3-D model can be realized from physical objects (according to a “reverse modeling” process) or directly assembling 3-D digital forms. 3-D modeling includes the modeling of the scene, lights, cameras, textures, using both 2-D (for example background images or the so called “impostor billboards”) and 3D elements. The characteristics of the 3-D are related to the ones of the object and to the aims of the representation. A model could present a photorealistic image or both iconic and symbolic representations.
BIM: Building Information Modeling is a process about the whole life-cycle of a building, from project, to construction, maintenance, management and dismantlement. BIM is based on the realization of the 3-D models, where the digital elements are constructive objects (walls, floors, windows, etc.) uploaded from predefined parametrized libraries. The objects relate to a database with the design information that allow structural, energetic, economic, timing, computing. BIM involves the architectural, civil engineering, and plant aspects, and it favors the interoperability between professionals that work on the same model. BIM rises for new building design, but its application to historic architectures (the so called HBIM) presents numerous matters, because it is difficult to reconcile the unique character of historical architecture made with artisan procedures, with parametric 3D objects from standardized libraries and typed databases.