One common usage for frequent, scheduled, scanning and ‘Diffing’ is with structural elements. In the case below, post-tensioned (PT) slabs and concrete walls were tested on every floor of a 22 story structure. Each floor received an average 7 scans and SKUR Diffs.
Overall, the frequent scanning and Diffing process provided three primary benefits.
First, the General Contractor was empowered to make a variety floor-by-floor adjustments to compensate for variances that generally ranged from 2-4 inches. This allowed for extraordinary confidence in the as-built structural elements with very little time lost for corrections.
Next, a wide variety of subcontractors were able to immediately install components without costly adjustments or holds. One example: facade and glazing teams required little time rigging for out-of-tolerance structural members.
Finally, the building now has a permanent record of all structural elements. The information and the resulting visualizations have aided in inspections, post-build modifications, and are beginning to be utilized now by the facilities management team.
Purchase of the high-resolution LIDAR scanner cost $80,000, onsite technician billed at $750/day (22 days, $16,500), and client purchased four 50 Diff packages ($40,000) for a total program cost of $136,500.
In addition to the numerous small adjustments made as a result of the scanning and Diffing process, three critical issues were immediately identified and corrected without causing any significant work stoppage, supply chain blockages, or rebuilds. The estimated cost savings of repairing these three critical issues at an early stage ranged from $500,000 to $675,000.
However, the ROI stated here is likely grossly understated because we cannot know the value of all the small changes made along the way. The time saved by the Facade team is estimated to be in the hundreds of hours. Also, the cost of the LIDAR scanner will be amortized to include it’s production value on other projects; realistically adding years of value to multiple projects.