High-Definition Survey of the Nancy Creek Shaft

PBS&J performed a detailed survey of a shaft located at the end of the Nancy Creek Tunnel.

PBS&J used a Leica HDS-2500 3D Laser Scanner to perform a detailed survey of a 75-foot diameter by 145-foot vertical shaft located at the end of the Nancy Creek Tunnel in Atlanta, Georgia. On this project, PBS&J and other subcontractors provided a variety of quality controls, for surveying, construction, environmental impact, and tunnel integrity. The point cloud data gathered with the laser scanner was referenced into Autodesk Land Desktop using Leica Geosystems Cloudworx. One-foot vertical sections were created, which were used to calculate the exact volume of concrete needed for each vertical foot.

Accuracy was critical due to the nature of the slip-form method used to fill the perimeter of the shaft. Laser scanning proved to be a valuable tool for measuring the areas of overbreak located at the bottom of the shaft. Had conventional surveying methods been used, acquisition of the data would have taken up to ten times longer and would have resulted in much less detailed data.