An Integrated Framework for BIM Development of Concrete Buildings Containing Both Surface Elements and Rebar

Abstract

As-built Building Information Models (BIM) are increasingly used to facilitate the management of all aspects of built infrastructure’s life cycle. Existing studies mainly focus on automating as-built BIM development for surface elements but often ignore embedded elements such as rebar due to the inaccessibility with typical sensing devices, such as image-based or time-of-flight-based methods. To tackle the issue, this research innovatively utilizes Ground Penetrating Radar (GPR) and the photogrammetry method together to generate BIMs for in-service buildings considering both surface elements (e.g., column, slab, wall) and rebar. As-built BIM for surface elements is developed at first and rebar is identified by using GPR. A calibration label is designed and attached to elements which are scanned by GPR device, and a series of images are captured from those elements and then used with other images to generate point clouds. Faster RCNN is utilized to recognize labels among all images. Then, an inverse photogrammetry approach is deployed to identify the scanned elements in BIM. By matching the recorded timestamps of GPR data and labeled images, links between the rebar in GPR data and elements in BIMs are successfully developed. Finally, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">IFC</i> is developed to generate as-built BIM models. Six cases studies demonstrate the system provides a highly automated procedure to develop as-built BIM, and rebars could be efficiently localized and projected into corresponding elements in BIM.