In the past decade, we have seen advances in technology that have introduced equipment and tools to leverage 3D engineered models for construction. Most notably is the use of automated machine guidance (AMG) for grading and excavating, fine grading and base preparation, and concrete paving. Until most recently, contractors had been using the contract plan sets to create their own 3D models. Although there has been a shift to deliver digital data as a supplement to the plan sets, only a few states have started piloting model-based deliverables by changing the medium of construction contract documents from paper or 2D PDF plans to include 3D model-based, digital information that is contractually binding.
While more state departments of transportation (DOTs) are interested in expanding the benefits of the model-based approach to project delivery, there are two distinct, but related barriers: (1) a lack of understanding of the tools currently available in the market to support the use of 3D models for inspection and (2) a lack of guidance for setting technical requirements for the procurement and selection of commercial off-the-shelf (COTS) tools or development of custom mobile applications.
Previous research has identified the wider issues related to the creation and use of 3D models. However, these prior studies have not examined how to perform detailed quality assurance checks without the use of plan sheets. Some efforts have been made to understand how high accuracy equipment (e.g. GPS) can be used to check location and elevations of specific points and record those points to create surfaces that are used for cutting cross-sections in the office for verifying earthwork quantities. However, to date not much has been done to use tablets with mobile applications that show the 3D model in a way the inspector can read the same information he/she was getting from the plan sheets.
The objective of this research is twofold: (1) Perform an evaluation of current COTS tools for viewing 3D engineered models in the field to inspect highway and bridge projects and (2) develop recommendations for procurement and selection of 3D model viewing mobile applications to perform construction inspection of highway and bridge projects. While there is progress towards using 3D engineered models for project delivery, technology is changing rapidly so it is important to conduct this study under an accelerated timeline.
State construction engineers would use the research to provide tools that construction inspectors and construction management staff can use for model-based inspection. The research should provide a thorough assessment of the software currently available, its capabilities and limitations. Understanding what is commercially available will enable state DOTs to procure and select tools that meet their immediate needs for viewing 3D models in construction for inspection tasks.