Using a laser scanner and a drone, a University of Nebraska-Lincoln (UNL) civil engineering professor and his graduate students analyzed the wreckage of a tornado that ripped through the town of Pilger, Neb., nearly one year ago and are soon releasing a report on the findings.
The tornado killed two people, injured 20 and destroyed dozens of homes and buildings, including St. John Lutheran Church. The Wisner-Pilger Middle School building was damaged beyond repair.
Days after the storm, assistant professor Richard Wood, graduate student Gulipiye Abudukadier and doctoral student Ebrahim Mohammadi examined six sites and, using data collected from a LiDAR 3D scanner and photogrammetry from a camera-equipped tethered drone, created a point-cloud model of the school building.
Their mission was to detect where engineering fell short – leaving key buildings vulnerable to the tornado's punishing winds – and to develop computer algorithms for remotely detecting structural damage caused by tornadoes, earthquakes and other disasters.
The model, which appears as a 3D image of the school building and can be rotated to different angles on the screen, helped them identify how the building was damaged by the storm.
Their soon-to-be completed report will be provided to the school district and posted to UNL's Digital Commons, an open-access online repository of academic papers and similar materials.
‘It is data mining,’ Wood says. ‘We assemble millions of data points and look for changes in the surface geometry to detect damage. We're statistically determining the potential quantity of damage, and the whole point is to do it in terms of minutes, not hours.’