We were approached by Atkins consulting Engineers through our JV partner Reach Engineering to provide a benchmark survey of a 2.5 metre diameter segmented concrete tunnel, which acts as a flood relief channel for the Prittle Brook.
Our remit was to survey the tunnel with millimetre accuracy to enable The Environment Agency to assess and fully understand the condition of their asset using a technology that would enable subsequent surveys to flag-up millimetre accurate changes.
With difficult and restricted access, distances between access hatches in excess of 1.5km and a 15-minute flash-flood warning a confined space manned-entry was not an option.
Our long-range, multi-task crawler was the only option for a survey with a 4.5km excursion range and provided an ideal platform for the Industry-leading Lidar system. The system has a repeatable accuracy of –1mm.
In addition to Lidar, the crawler was fitted with low-light, high resolution colour cameras and high intensity variable lighting pods, mounted on a pan & tilt head to provide additional useful visual data.