Bragg Crane & Rigging Overhauls Hydroelectric Facility’ s 75-Ton Bridge Cranes
Spotlight Rigging By Seth Skydel
Innovative Solutions and Custom Equipment
Bragg Crane & Rigging Overhauls Hydroelectric Facility’ s 75-Ton Bridge Cranes
In operation since 1925, the PG & E Pit 3 hydroelectric powerhouse in Burney, California, provides electricity to northern and central parts of the state. In 2021, Bragg Companies undertook a major overhaul of the facility’ s two 75-ton bridge cranes that involved innovative rigging solutions, and new and customized equipment.
The challenges for the project were considerable, noted Justin Lambert, general manager of Bragg Crane & Rigging, including:
• The only engineering drawings available were more than 100 years old and lacked details such as the weight of the trolleys, bridge cranes and girders and catwalks.
• The bridge cranes were positioned 53 feet above the floor, leaving almost no headroom below the facility’ s concrete roof and steel trusses.
• The bridge crane girders were connected at both ends and had to be removed at the same time.
• No work was allowed above the hydroelectric facility’ s turbines, leaving a small 40- by 30-foot work area.
• The facility’ s basement and sub-basement restricted floor loading.
• Access was limited to overhead door openings.
• The hydroelectric facility would remain operational throughout the project, requiring an extensive effort to protect against contamination of the watershed.
“ Working with loads that have to be supported from below rather than lifted, elevates risk,” Lambert said.“ By measuring and photographing every part of the facility and using conservative weight estimates based on experience, our teams set out to develop a plan to replace the bridge cranes and catwalks. Every pound and every inch had to be accounted for so we did not overload equipment or exceed available dimensions.”
Bret Hanley, superintendent at Bragg Crane & Rigging was onsite for the duration of the project. To start, he pointed out, crew members were required to complete hydroelectric and substation, boom, scissor lift and gantry training. When the project
Even with a 35-foot extension, Bragg’ s gantry crane was still short of the height needed, requiring a custom-designed subframe to make up the difference.
Once prep work was completed, Bragg brought in a 700-ton capacity gantry crane for the hydroelectric powerhouse project.
12 CRANE HOT LINE ® October 2024 • www. cranehotline. com