Pedestal Crane Slew Bearing Gearbox Changeout using a Jacking System

Intro

‘CIC-Alatas’ – our joint venture in Brunei recently completed the replacement of the slew bearing on our client’s Favelle Favco 7.5/10k pedestal crane. This was the first time the slew bearing had been replaced and as such a full scheme had to be designed, manufactured, and the project delivered as a complete turn-key package.

This was the first of two cranes that need to have their slew bearings replaced using a jacking system and as such Alatas offered a modular design solution where +75% of components were interchangeable between the different crane configurations.

BACKGROUND

‘CIC-Alatas’ has an operations and maintenance contract with our customer that covers over 80 offshore cranes. Each crane has a 6-year comprehensive refurbishment as part of the maintenance strategy delivery. Because the slew bearing on this crane had never been replaced before, the customer decided to replace it with a new one, allowing for a fresh datum of its state to be obtained for use in a redesigned maintenance strategy with a greater focus on condition monitoring.

ALATAS’ SOLUTION

Alatas’ solution was to provide a complete turn-key solution utilizing multi-office working together to ensure a high quality and efficient service to the client.

• CIC-Alatas engineering team completed the initial site survey of the crane to gather crucial information to allow the design process to be completed.

• Alatas UK design team developed the jacking system solution.

• Alatas Singapore fabricated the jacking system’s structural components.

• Alatas Indonesia supplied the specialist jacking console and hydraulic cylinders.

• CIC-Alatas engineering team produced the detailed work packs and RAMS.

• CIC-Alatas engineers and field service techs completed the full onshore trials and offshore delivery of the project.

Job Scope

Jacking Frame Design

• Review crane data and select the most suitable jacking method
• 3D Model Crane
• Design Jacking Frame around the design and dimensions of the crane Pedestal and Chassis
• Check Stress Valves using predicted loads
• Design a skidding frame to allow efficient replacement of slew bearing

Jacking Frame Fabrication

• Establish ITP and Quality Plans
• Fabricate Jacking Frame
• Supply of all Fixings
• NDT and Testing
• Provision of Manufacturing Record Book and Certification Pack

Jacking Frame Construction

• Manage construction of Access and Load Bearing Scaffolding
• Lift Plan and Rigging for lifting Jacking Frame Components into position
• Assemble and Test the Jacking System
• Pre and Post NDT of Welds

Slew Bearing Changeout

• Disconnect and Remove of Slip Ring
• Remove both Slew Motors, Brake Packs, and Gearboxes
• Remove Slew Bolts
• Controlled Trial Lift to determine the Centre of Gravity
• Jack Up Crane
• Check Pedestal Flatness using Laser and provide a condition report
• Remove Old Slew Bearing and Install New Slew Bearing
• Jack Crane Back Down
• Install and Tension Inner and Outer Slew Bolts (Rotabolts)
• Re-Connect Slip Ring

Commissioning

• Full Visual Inspection
• Backlash, Rocking Motion, and Teeth Flank Contact Check completed
• Function Test
• Load Test using water bags and load cell

Pedestal Crane Slew Bearing Changeout using a Jacking System Gallery