Gantry Structural Assessment

What the client wanted

KBS Maritime required a detailed structural assessment of an existing crane gantry within a refit dock at HM Naval Base Portsmouth. The objective was to verify the condition and load-carrying capacity of key infrastructure assets while maintaining uninterrupted operations within this busy naval facility.

The Challenge

Removing the masts from the world's oldest commissioned warship presented a unique combination of engineering, operational and heritage risks. The project involved lifting irreplaceable historic structures using a 750-tonne crane and specialist lifting equipment, with all works carried out overnight to maintain a controlled and safe working environment. 

The client needed independent engineering assurance to validate the lifting strategy, manage project risks and support the safe execution of this highly complex operation.

Our approach

Attis provided engineering and safety expertise throughout the planning and delivery phases of the project. Acting as a trusted advisor and critical friend, we helped finalise the mast lift safety case, provided ongoing assurance, monitored progress and supported the project team throughout the overnight lifting operation. 

The Challenge

The crane gantry and supporting structures play a vital role in dockside operations and vessel maintenance activities. However, accurate structural data was required to support asset management decisions, prioritise repairs and ensure continued safe operation.

The client needed:

• Verification of structural integrity and loading capacity.
• Reliable engineering data to inform maintenance planning.
• A non-intrusive testing solution that would not disrupt ongoing naval operations.
• Confidence that future vessel maintenance programmes could proceed without delay. 

The client needed critical structural assurance that enables safe operations, informed asset management and continued support for Royal Navy vessel maintenance.

Our approach

Attis delivered a highly responsive structural assessment using advanced non-destructive testing techniques. This enabled our engineers to gather high-quality structural data without affecting critical dockyard activities.

The project included:



• Detailed survey of the gantry structure and dock supports.
• Verification of load capacities for the concrete deck and metal walkway.
• Assessment of structural performance to support informed asset management decisions. 
  

Outcomes

• Comprehensive understanding of the gantry's structural condition. 
• Verified loading capacities for key infrastructure assets. 
• Evidence-based prioritisation of repairs and maintenance works.
• No disruption to naval base operations throughout testing. 
• Improved decision-making to support future vessel repair and refit programmes.
  

"The testing of the gantry structure was carried out professionally and without disruption to ongoing naval base operations. The verified loading capacities have enabled KBS Maritime to inform the asset management plan and to prioritize repairs. This in turn allows us to identify temporary solutions in order to receive Royal Navy vessels into the dock for planned repairs without delay or disruption."

Nick Tate

Naval Base Chief Engineer, KBS Maritime