Generative HBIM modelling to embody complexity (LOD, LOG, LOA, LOI): surveying, preservation, site intervention—the Basilica di Collemaggio (L’Aquila)

Abstract

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 “Re-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 decision-making processes among the different actors involved in the preservation process. The Basilica of Collemaggio has been re-opened 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 theoretical 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-complex-detailing 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 “BIM 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 interoperable cooperative HBIM habit among multi-actors across all the phases, spreading its usability after the restoration process. On the lesson learnt, the process of updating the current Codification criteria (UNI11337-2009) has been started with a draft proposal stimulating the debate for the future of HBIM adoption in the case of restoration, preservation and maintenance (UNI11337-2017): in the conviction that transferring the HBIM richness into the Life Cycle Management process will allow multi-actors to take in account the knowledge and information gained during the restoration, integrating the as-built updating and keeping updated the monument monitoring during the time being.