Overview
Uponor, a global leader in plastics-based infrastructure systems, was preparing to launch a new product and was ready for field testing. Their new underground modular design required in-field deflection measurements under varying backfill and load conditions. Uponor needed experts to not only capture the data with accuracy, but to develop a custom scanning solution that went way beyond the ordinary. Spatial Acuity was called in and devised a plan to address the following roadblocks:
- A scan operator could not be present in the modular unit during testing;
- Each 3D scan must share coordinates with the others for comparison;
- Real-time deflection feedback was required at each loading stage.
Process
Before mobilizing the laser scanning team, several key test methods needed to be ironed out:
The modular system was to be buried and the backfill compacted in stages and a baseline scan of conditions needed to be taken just prior to loading. The key challenge was tying all subsequent laser scans back to the baseline scan; in a laser scanning situation such as this, one would typically use specialized targets which serve as a constant point of reference for all laser scans to overlay – this would not work given that the targets would have to be placed inside of the modular unit and would be subject to movement as compaction of the top of the container and total container deflection increased through the stages of testing.
To address this, the Spatial Acuity team worked closely with Uponor engineers and considered the base compaction specifications as well as the expected behavior of the modular unit under load. It was determined that a 1” diameter bore could be placed in 3 locations at the bottom of the modular unit in order to securely mount the targets in order to have the reference points required to accurately place the scans. Large rebar was sledged in with a small amount of clearance from the modular unit and a spherical target was magnetically adhered to the top of each section of rebar. This meant that the modular unit was free to move under stress and Spatial Acuity’s targets would remain completely stationary and unaffected. With stationary targets, the team could tie all of the test scans back to common coordinates for comparative analysis.
The next step was to figure out how to control the scanner and data collection if the team could not be present in the underground unit. Sure, most scanners have built in Wi-Fi these days, but buried underground with a 3’ manhole rendered the typical Wi-Fi solution unusable. This was an easy problem to tackle for the Spatial Acuity team, as they have developed a custom Wi-Fi system that allows the laser scanning team to control the scanner from over a mile away – even without line of sight to the scanner itself. The final obstacle was near real time deflection reporting – prior to moving to the next stage of stress testing, Uponor engineers needed confirmation that the modular unit deflected within design expectation and remained well within their planned safety margin. The on-site laser scanning specialist – well versed in all aspects of the laser scanning process – remotely extracted scan data and analyzed it from a laptop in the field. Quick measurements were taken and within one hour of the completed scan, the results were delivered to the client’s engineering team for review.
Outcome
Over a period of one week, data was captured under all required test load conditions. By compiling the data together using the unique stationary targeting solution, Spatial Acuity issued a layered 3D point cloud to the Uponor team for further analysis; each layer was aligned to a control scan and was easily discernable. The client’s modular unit performed well within expectations and the field test was considered a success.
