Utilizing 3D Digital Design Data in Highway Construction - Case Studies
The case studies FHWA-HIF-17-027 illustrated that the survey data was a significant factor in both the usability of the original design data and the root cause of construction issues.
The Federal Highway Administration (FHWA) conducted a comprehensive case study of how 3D digital design data was used successfully by both the owner agency and the construction contractor during six specific highway construction projects.
For more information please see all case study https://www.fhwa.dot.gov/construction/3d/hif17027.pdf
CONCLUSION on Page 178:
"It was surprising to find that the issues with design data—such as inconsistency with the design intent in the plans—took time to resolve, but had a minor impact on construction outcomes. The construction issues were a result of the unreliable original ground survey that the design was
"It is important that the mapping be collected with a total station or static lidar if the intent is to control yields. Likewise, the AMG system for grade control needs to use RTSs or mmGPS. GNSS does not have the accuracy to control thickness to the extent needed for depth and yield control. The accuracy needs for AMG concrete paving are often underestimated."
"Vertical accuracy is paramount for AMG paving systems."
"...static lidar provided the most complete and most precise data in the shortest amount of time."
"The Utah and Virginia projects both had issues with the original survey data. In Utah, the root causes were insufficiently accurate control and insufficiently precise topographic data collection."
"The original ground survey must be established from a control network that has vertical precision established through digital leveling and must be captured using RTS, static lidar, or instruments with equivalent precision. "