Interior Rubble Voids Analysis
The 2021 Champlain Towers South Condominiums collapse in Surfside, Florida, resulted 98 deaths. Nine people are thought to have survived the initial collapse, and might have been rescued if rescue workers could have located them. Perhaps, if rescue workers had been able to use robots to search the interior of the rubble pile, outcomes might have been better.
An improved understanding of the environment in which a robot would have to operate to be able to search the interior of a rubble pile would help roboticists develop better suited robotic platforms and control strategies. To this end, this work offers an approach to characterize and visualize the interior of a rubble pile and conduct a preliminary analysis of the occurrence of voids. Specifically, the analysis makes opportunistic use of four days of aerial imagery gathered from responders at Surfside to create a 3D volumetric aggregated model of the collapse in order to identify and characterize void spaces in the interior of the rubble.
The preliminary results confirm expectations of small number and scale of these interior voids. The results can inform better selection and control of existing robots for disaster response, aid in determining the design specifications (specifically scale and form factor), and improve control of future robotic platforms developed for search operations in rubble.
Research Team: Ananya Rao, Robin Murphy, David Merrick, Howie Choset
Aerial imagery collected to support the Surfside disaster response was processed to create an aggregated 3D model of the disaster site in the form of a point cloud stack (right), which was then analyzed to find and characterize voids. For contextualizing this 3D volumetric model, an aerial view of the Surfside collapse site is shown (left).
Cross sectional views are taken into the aggregated 3D volumetric mode to examine of the rubble pile on a 4m x 4m grid. The slices are 1m x 64m in the XY plane, and have the depth of the entire rubble pile. Here the slices are depicted on the orthophoto mosaic constructed from images gathered during a single UAS flight on June 27, 2021.
The locations and estimated XY plane bounding boxes of the six identified voids are overlaid on the orthophoto mosaic from June 27, 2021.
Some material was removed in the pink void region between June 27, 2021 (top left) and June 28, 2021 (top right). There appears to be some slabs removed, which is consistent with the shape of the top of the void space seen in the XZ plane cross sectional view of the pink void (bottom). This implies that the pink void was naturally formed during the collapse.
Some material was removed in the pink void region between June 27, 2021 (top left) and June 28, 2021 (top right). There appears to be some slabs removed, which is consistent with the shape of the top of the void space seen in the XZ plane cross sectional view of the pink void (bottom). This implies that the pink void was naturally formed during the collapse.
By inspecting oblique imagery of the purple void (right), and relating this to a cross sectional view of the purple void (left), it is seen that large objects and features are reasonably recognizable and consistent between the imagery and the layers of the constructed 3D volumetric model.