Guiding a 3,500 ton Structure with Centimeter Precision
Construction of the Second Ondo Bridge (provisional name)
Using the nation’s largest crane barges, the construction involves laying bridge girders weighing around 3,500 tons in a single operation. The length of the girders is around 200 meters.
Guiding the crane barges and bridge girders accurately and safely
The main feature of this guidance system is that in addition to a system for the monitoring of the orientation and position of the bridge girders, and the guidance of the cranes used in the construction of the Tokyo Gate Bridge, a monitoring system to ensure that the girders do not encroach on space outside of the construction zone was also developed. Thanks to this system, construction can be carried out safely, and objects being lifted by the crane barges are prevented from entering airspace above people in residential areas and areas outside the construction zone (safe areas).
The positions of crane barges and bridge girders are displayed simultaneously, and accurate guidance to the installation positions is performed while displaying the clearance between the ends of the bridge girders and areas outside the construction zone. Alerts and warnings are issued in accordance with the clearance. The software allows the barge captains and crane operators to check positioning in real time, on an overhead view diagram as well as numerically. To carry out guidance with this system, two GPS units were installed, on the crane barge as well as the bridge girder.