Structural Health Monitoring (SHM), Heritage building information modelling (HBIM) and remote sensing for existing bridge.

Much of the world’s historical, artistic, and cultural built heritage has internal or exposed damage and require ordinary or extraordinary maintenance. From an engineering point of view, several techniques have been developed over time to solve this problem, such as structural health monitoring (SHM) which involves the management of structural damage using internal or external sensors or through visual damage inspection. As for the existing structures, after the data is generated, it must be collected, managed and stored in an appropriate manner and consequently one needs to work in an HBIM context, also known as Historical Building information Modelling. Following this methodology, it is essential to work with a unified and parametric 3D model, able to manage new model integrations by updating its database with different types of data. In most cases, existing structures are characterized by complex geometries that would have to be modelled directly in a BIM environment, with a great deal of time. With this in mind, new techniques have been developed such as Scan-to-BIM or Mesh-to-BIM which are based on remote sensing through the use of laser scanners, photogrammetric techniques and, recently, also drones with cameras that have characteristic of rotating 180°. These techniques make the reconstruction of the model more expeditious, even if currently there are still problems of interoperability between software to use them in an optimal way. The main objective of this research is to generate a workflow to perform the detection and characterization of damage in a bridge, through the SHM and remote sensing techniques, working in an HBIM environment. At the beginning, we looked for a methodology to import the mesh and texture of a 3D object, a Rubik’s cube, into the Revit software, following a mesh-to-BIM procedure which, however, turned out to be a non-automatic and very time-consuming procedure. Another methodology was then followed, namely scan-to-BIM, by importing the dense point cloud of a damaged pier cap beam of a dismantled bridge into the Revit software and identifying the damage through a user interface, with the help of CloudCompare software and Dynamo. After finding a quick methodology, the same work-flow was followed for the Stura Bridge located between Turin and Turin-Caselle Airport. In the first phase, an in situ survey of the bridge was carried out with laser scanner and drone. The point clouds were generated and processed using the software Faro-Scene, Agisoft Metashape and CloudCompare. Subsequently, through the use of Recap, the point cloud was imported into Revit. Finally, damage was identified through CloudCompare, software capable of managing more detailed dense point clouds, and with Dynamo a user interface was created to import the damage identified, directly into Revit. To conclude, it is possible to guess that in future it will be possible to automate different processes in order to directly implement SHM and remote sensing techniques directly in an HBIM environment, but currently there are still problems due to interoperability between software that make some phases the process still manual, time-consuming and at best cases semi-automatic.