From an article in the TREKK Lidar eNewsletter.
TREKK used mobile LiDAR to scan the roadway imaging in two hours along the initial 2.2-mile Main Street route without disrupting traffic or traffic control. A total of 2GB of scan data was collected and 4 GB of high-definition georeferenced images was used to create a CAD drawing containing a Triangle Interpolation Network (TIN) and topographic features. Simultaneous Localization and Mapping (SLAM) technology was then used for underground features like electrical vaults, manholes and basement structures. These two processes combined into the same coordinate system and enabled the design team to avoid conflicts of the below ground features with the above ground design, by creating a complete and more accurate virtual environment.
Creating highly-accurate underground utilities maps is one of the most demanding forms of surveying. Most vault environments are hazardous, and work must be conducted in narrow, dark, confined space environments. GPS coverage is limited or nonexistent. SLAM technology lowered into the underground space allows documentation without entering the below ground environment. Electrical vaults require nonconductive access and traditional survey rods pose hazards. The combination of high-voltage electrical cables with an aging infrastructure can exponentially complicate even the most routine vault-related task making SLAM technology perfect for acquiring this data.
“Using SLAM to gather comprehensive underground data in vaults and manholes increases safety throughout the process of acquisition.” said Trent Robinett, TREKK Partner. “In a matter of minutes, we captured 3D scan data needed to generate an accurate 2D outline of the vault limits creating a much more comprehensive and complete survey than what could be acquired by a manned entry. Multiply that by the 70 utility vaults and manholes we acquired, and it is a tremendous cost savings for the client.”
As part of our varied services, TREKK also provided CCTV inspection to determine the condition of the stormwater and sanitary sewer lines in the roadway. We conducted design and boundary survey, easements and exhibits. We also self-performed the utility locates throughout the entire project corridor, including some of the most complex utility corridors found in the City. TREKK worked through the completion of the project by providing construction staking. This gave us a first-hand look at how good subsurface information can make construction more efficient and reduce the number of change orders.
The KC Streetcar serves as a great example of a city investing in transportation infrastructure to spur development. TREKK continues to provide topographic and mobile LiDAR survey as part of the Streetcar’s Main Street and Riverfront Extensions.
For more information on documenting utility vaults with lidar CLICK HERE.
