Reality Capture for Tornado Damage to Structures

Wind speeds and velocity structures in tornadoes are largely unknown, since direct measurements are difficult and rare. Structural engineers, atmospheric scientists, and catastrophe modelers must therefore utilize “proxy” methods (such as the estimation of structural resistances that have been exceeded) to better assess tornado and other windstorm risks to achieve safe yet economical designs. Damage to simple engineered structures is of particular interest, since the resistance of such structures can often be readily estimated. Such determination requires accurate measurement of structural member sizes, which can be prohibitive due to time, site access, and safety issues. A late-2015 intense tornado outbreak severely damaged a group of engineered structures at an industrial facility near Pampa, TX. This facility contained multiple engineered structures for which structural resistances could be estimated, thereby enabling the estimation of tornado wind speeds required to cause the observed damage. Due to safety and security liability concerns, facility owners restricted access to the site. Investigators were, however, permitted to acquire remote-sensing data to preserve the damage scene for subsequent detailed analysis. Ground-based LiDAR scanning and terrestrial digital imaging from the property line as well as aerial and satellite imaging provided effective solutions for rapidly, safely, and accurately preserving the damage scene. The multi-platform data collection has facilitated and evaluation of remote-sensing platforms for their utility in rapidly capturing and preserving damage scenes via 3D models and visualization.