A Federated HBIM Workflow for Complex Heritage Conservation: Data Integration, Automation, and Construction-Phase Support for the Floor of the Holy Sepulchre Basilica

The management of complex heritage conservation projects requires the integration of heterogeneous datasets, multidisciplinary expertise, and information generated throughout investigation, design, construction, and maintenance activities. Although Heritage Building Information Modelling (HBIM) is increasingly adopted as a framework for organising heritage information, its implementation in complex conservation projects remains challenging due to the coexistence of multiple disciplines, modelling granularities, and information requirements. This paper presents the development of a federated HBIM system for the conservation of the floor of the Basilica of the Holy Sepulchre in Jerusalem and, starting from this real multidisciplinary implementation, derives a generalised methodological workflow for similar heritage conservation projects. The proposed workflow consists of four main phases: (i) definition of project objectives and information requirements, (ii) acquisition and organisation of multi-source datasets, (iii) development of a federated HBIM architecture integrating modelling, information management, and automation, and (iv) operational use of the federated model throughout the conservation process. A key aspect of the proposed approach is the organisation of federated sub-models according to both disciplinary responsibilities and specific operational purposes, allowing different geometric and semantic granularities to coexist within a coordinated information environment. The study also demonstrates the enabling role of automation in supporting the management of highly granular datasets and repetitive information management tasks. The application to the Holy Sepulchre Basilica demonstrates the applicability of the proposed workflow in a real multidisciplinary conservation project, while the abstraction process provides a transferable methodological framework for similar heritage conservation contexts.