In December 2012, EniServizi (the Italian multinational energy company), after the Earthquake that occurred at L'Aquila in April 2009, decided to undertake the project BRe-start from Collemaggio^, funding around 14 million Euro to restore the Basilica di Collemaggio. EniServizi, aware of the BIM potential role in the complex building and infrastructure domain in the world, required an advanced HBIM based on laser scanner and photogrammetric surveying to address decisionmaking processes among the different actors involved in the preservation process. The Basilica of Collemaggio has been reopened to the public on December 2017. This paper tries to make a synthesis of the different lessons learnt, in relation to both positive and critical aspects relating HBIM feasibility, sustainability and usefulness to the challenging restoration and preservation field. The theo-retical and practical HBIM approach here tackled overcomes the current BIM logic based on the sequential process adopted by the AIA and NBS Level of Development (LOD), characterized by a simple-to-complexdetailing process, working in the new construction domain and generally following the conceptualizing phase, the preliminary design, the executive design, the construction phase till to the facility management. A complex-mixed LOD approach, able to entail the richness, unicity and multiplicity of each component and to get the maximum degree of knowledge, has been experimented in order to derive informed decisions in terms of preservation, restoration and management since the starting phases of the architectural design. To this aim, a Level of Geometry (LOG) coherent to the Level of Accuracy gained by the high-resolution surveys has been adapted to the specificity of the restoration process of a historic monument and is here proposed through different Grade of Generation (GOG) protocols developed in the object modelling to support the preliminary and definitive design proposal of the conservation plan of the Basilica. Particularly, a NURBS-based parametric generative modelling process (GOG9-10) is here proposed in order to get models BBIM abled^ to describe the complex geometry and to match the related information. Specific Level of Information (LOI) has been introduced to support the preservation process, to document the as-built and the management of the building after the intervention, moving HBIM toward multi-actor domain. Given the effort required by such approach, obtaining a cost-effective HBIM modelling embodying the complexity of each damaged element as acquired by the surveys (i.e. walls, pillars, vaults, beams) represents a challenging issue. The result of the overall process aims to contribute in lowering the initial HBIM modelling costs by deploying a sustainable complexity delivering protocols and specification and by boosting at the same time an interop-erable cooperative HBIM habit among multi-actors across all the phases, spreading its usability after the restoration process. On

Commission VI, WG VI/4 KEY WORDS: HBIM, NURBS, PARAMETRIC MODEL, LOD, LOG, LOI, FEA, TOOLS, PRESERVATION ABSTRACT:In December 2012 ENIservizi (the Italian multi-national energy agency operating in many countries), after the Earthquake that occurred in April 2009, decided to undertake the project 'Re-start from Collemaggio' with the aim of giving new hope to the L'Aquila community, funding around 14 million Euro to restore the Basilica di Collemaggio. The Superintendence Office carried on the restoration project with the scientific support of the Università degli Studi de L'Aquila and the Università La Sapienza di Roma, under the coordination of the Politecnico di Milano. ENIservizi, aware of the BIM potential in the complex building and infrastructure domain in the world, required an advanced HBIM from the laser scanner and photogrammetric surveying to support the diagnostic analysis, the design project, the tender and the restoration itself, today still on course. Plans and vertical sections were delivered (2012) starting from the surveying campaigns (February and June 2013), together with the first HBIM advancement from the end of 2012 in support of the preliminary-definitive-executive steps of the restoration design project (2013-14-15). Five years later, this paper tries to make a synthesis of the different lessons learnt, in addition to the positive and critical aspects relating HBIM feasibility, sustainability and usefulness to the challenging restoration work. In particular, the Collemaggio BIM experience anticipated the new Italian Public Procurement Legislation (D.Lgs 50/2016, Nuovo Codice degli Appalti pubblici) aligned with to the EUPPD 24/2014: the EU Directive on Public Procurement asked all the 28 EU countries to adopt building informative modelling by February 2016 in order to support the whole LCM (Life Cycle Management), starting from the project and the intervention, through rewarding scores or mandatory regulations. Many analyses foresees to save from around 5% to 15% of the overall investment by adopting mature BIM (Level 3 to 5), particularly 4D remotely controlled BIM in support of the LCM, as in the case of maintenance and management process. The tender for Basilica restoration was published in 2015: the process was not developed enough to introduce selective criteria based on BIM adoption by the Construction Industry due to the lack of legislation at that time and the lack of BIM skills among the companies. Nevertheless ENIservizi also separately funded aside the HBIM of the Basilica to tackle an advanced BIM able to address decision-making processes in the heritage domain among the different actors: to support operators, architects, structural engineers, economic computation, construction site management and restoration, the theoretical and practical approach adopted by the HBIM, overcame the current logic based on sequential LoD (from simplex to complex, from the preliminary to the executive design) that is typical of new constructions in favour of a complex LoD approach that could guar...

The earthquake occurred on the 6th of April 2009 in the Abruzzo Region of Italy, seriously hit the Cultural Heritage (C.H.) patrimony with major destructive effects on L'Aquila, a city of 70,000 inhabitants with the size and the historical and strategic importance of the Region capital. The emergency activities to protect the C.H. have been developed on two parallel levels: (1) survey and assessment of damages, (2) implementation of temporary safety measures. The organization of the emergency actions was managed by a centralized structure, the so called Function 15 "Protection of Cultural Heritage", that coordinated the surveys of protected buildings and the design and implementation of temporary safety measures. This allowed the cooperation among different involved subjects (Ministry of Cultural Heritage officers, experts on structural engineering, architects and historians from Universities and private offices and fire brigade teams). The first level of the operating process was carried out on site by expert teams filling up dedicated survey forms for churches and palaces, developed by 123 106 Bull Earthquake Eng (2011) 9:105-138 Heritage); the forms were based on the standardization of damage survey allowing for its immediate interpretation. The second level was based on the past experience in the field of temporary safety measures; the idea was to provide a technical and scientific support in order to assist the work of fire brigade, highly experienced professionals in the "emergency" field. After the first emergency phase the damages of the most important buildings were more carefully investigated and the possible damage progression constantly monitored. The paper presents the case of the Spanish Fortress in L'Aquila, severely damaged by the earthquake; the description concerns the definition of the damages and the interpretation of the activated collapse mechanisms. Finally the design of the provisional strengthening interventions and the on site diagnostic investigations are presented.

<p><strong>Abstract.</strong> The development of advanced survey techniques in the last years is offering a wide set of tools for implementing the building analysis. In the preservation field, the use of 3D interactive models is a prerogative of few and rare excellent cases and the information contained in high-resolution virtual representation are only partially developed. In the past centuries, the representation was centred on the theoretical roles of the descriptive geometry devoted to the representation of the architectural elements complexity in the space to manage the construction site process. It has been progressively lost the past skill to managing 3D objects in the space. Being HBIM based on 3D solids representation, the theme of the 3D model comes back to the foreground. The complexity of the architectural heritage and its components is evidencing a gap of best practices, protocols and specification in the HBIM-modeling. Do-It-Yourself modeling process has been characterised by the first phase of HBIM generation in the last years. Modeling phase within HBIM is left to the single responsibility, with lack of specification on the accuracy and level of geometry.</p><p>This paper presents a first tentative to summarize the relationship among the surveying accuracy, the Level of Geometry and the Level of Accuracy (LOA) of each BIM object, starting from a series of experiences, in which advanced survey techniques were applied to condition assessment required by architectural preservation HBIM approach. The objectives of the surveying and HBIM can change for different aspects: but in the preservation context the specificity of each single objects and their complexity need to be taken into account. As in the surveying, the choice of a scale implies a range of accuracy and tolerance in the data acquisition and processing, in HBIM modelling the choice of the Grade of Accuracy drives within the Level of Geometry the scale model that is expected to be performed and required by the different actors involved by the different phases (i.e. restoration, Energy Efficiency, Finite Element Analysis, CoSiM). On the base of different experiences occurred in the last years, the specifications conventionally adopted for the surveying have been here proposed and extended to the HBIM domain, particularly in the modelling of objects, in order to classify different accuracies. A transparent choice of accuracy allows to define the LOG and to support the adoption of the proper Grade of Generation among the different options (GOG1-10) in function of the point clouds geometry and of the scales chosen by the different actors. The architectural scale together with the urban scale (Heritage Urban Level) is considered as well to keep advantage of a multi-resolution model, diversified in function of the objectives, thus of Level of accuracy (and Level of Information) and Level of Geometry.</p>

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