May 17, 2021 - Rubin Observatory now has a permanent, operational overhead bridge crane (OBC) in the dome, thanks to the combined efforts of many organizations and individuals. This 18-ton capacity OBC will be used to continue telescope assembly and system integration during construction, and will facilitate maintenance and repairs throughout Rubin Observatory operations.
The dome OBC, which was installed in late April 2021, replaced a temporary bridge crane that was installed in the dome in early 2020. The temporary crane kept the Rubin construction project on schedule—the Telescope Mount Assembly (TMA) team was ready to start assembling the telescope support structure while the permanent crane was still being manufactured and tested in Italy. But why not just keep the temporary crane in place? Because the permanent OBC has a higher capacity, more specialized control, and greater precision of movement than the temporary crane —all of which are essential for long-term needs in the facility, including installation of the camera and optics on the TMA.
A lot of preparatory work was done before the crane was lifted into the dome on April 16, 2021. This work included pre-assembly and dimensional verification of the bridge structure and hoist on the ground; installation of cabinets, rails, cables, and safety devices, on the crane; and finalizing a detailed plan for configuring the crane and conducting the lift. As with other major lifts of heavy equipment into the dome, environmental conditions (including wind speed) had to be verified and approved on the day of the lift. Also as a safety precaution, all personnel on site were informed when the lift began and ended. The OBC was lifted by a 220-ton capacity mobile crane operated by a father and son team (operator and rigger) who stayed in constant contact throughout the maneuver. A team of assemblers, skilled in safely working at heights, was in place at the top of the dome, ready to receive the OBC and finish the installation after it had been successfully placed on its rails. All these activities were carried out with strict adherence to our Covid Exposure Prevention Plan.
After the connection of electrical power, a series of adjustments, alignment of the rails, and functionality tests, the OBC was ready to be operated. Load testing at 125% of the crane’s rated capacity and certification was scheduled to take place on May 14th. Following that, the new permanent dome bridge crane can be used for construction tasks by the Dome, Camera, and TMA teams working in the facility as they continue assembling the telescope and getting the facility ready for operations.
Thanks to the teams from Mill Montajes Llanquitruf (mechanical assembly), Simaq (mobile crane), Oscar Rivera (surveyor), Konecranes (Chilean crane support), Meloni (OBC fabricator), EIE Group (dome contractor), and Rubin Observatory for helping to achieve this milestone safely. More photos of the dome overhead bridge crane and its installation can be viewed in the Gallery.