NREC developed a 3D imaging system for underwater excavation
and placement of caissons that Kajima Corporation used to
support the foundation for the Nagasaki Bay Bridge.
Kajima contracted with NREC to develop an imaging
sensor system that could see through dust and effectively
map and display the interior of the caisson digging area to
personnel operating below ground cutters. In less than one
year, NREC designed, built and fielded the system in Japan
where it supported the placement of a 42 meter deep caisson
in solid bed rock.
The 3D sensor system reduced labor cost by enabling more
efficient teleoperation of the caisson cutting and material
removal process. It increased safety by reducing the need
for workers to directly inspect the pressurized excavation