400Te SWL Deck Crane Boom Foot Pin and Bearing Changeout

Intro

Alatas was tasked by a client to provide a turnkey package to change out an asset’s 400Te SWL deck crane boom foot pins and bearings. The package consisted of site surveying/planning, design engineering, project management, bespoke fabrications, part supply, and site implementation.

BACKGROUND

A client was having problems with their deck crane operation. Excessive noise was also detected from the boom foot to chassis pinned connection.

The 116Te boom would need to be properly supported and the pins removed in order to evaluate the problem. The bearings also needed to be replaced, thus the boom support technique had to include a mechanism to elevate the boom foot out of position clear of the clevis’ and lower it for re-installation.

ALATAS’ SOLUTION

Alatas structural and project engineers were mobilized for an initial site visit to gather necessary data and propose the intended method to take forward into a detailed design phase.

Alatas’ design engineering department designed a complex arrangement of bespoke retrofit weld-on support steelwork, hydraulic cylinders, and rigging points to control the 116Te boom during the pin removal. This system was devised whilst allowing the boom to remain in its boom rest at a 10-degree angle from horizontal. [2] This removed the need for multiple boom support towers built up from the deck level and the quayside ultimately reducing the overall cost and implementation time whilst maintaining a safe/workable solution.

The solution was based on the information regarding the boom weight and center of gravity (COG) concerning the boom rest. The COG position was close to but forward of the boom rest which acted like a seesaw and created a much smaller reaction force at the boom foot position allowing for less substantial steelwork to be used. [3] The sliding influence of the boom caused by the 10-degree angle of the boom in the rest was counteracted by heavy-duty turnbuckles attached to the boom rest itself via retrofitted pulling padeyes. [4]

The design package was fabricated by Alatas and third-party contractors and all equipment/personnel were mobilized to the site where the procedure was safely and successfully implemented. The bearing was found to have collapsed which caused difficulty during the removal phase. This required additional resources to remove the pins using thermal lancing. The new pins were bathed in dry ice to shrink them before re-installation.

Job Scope

• Carry out a site survey and determine a suitable methodology for changeout
• Gather data and drawings
• Carry out conceptual and detailed design phases for the boom support steelwork and rigging
• Carry out design calculations, and FEA/stress analysis of design components under design loads
• Design of pin and bearing pulling equipment
• Specification of rigging and hydraulic jacks/cylinders
• Complete fabrication and arrangement drawings for designed components
• Provide lifting/rigging methodologies for installation of components and scope implementation
• Create a work pack and method statements for scope implementation.
• Contractor fabrications and supply of equipment
• Equipment and Personnel Mobilisation to the site to complete the scope
• Commissioning of crane post-scope completion

400Te SWL Deck Crane Boom Foot Pin and Bearing Changeout Gallery