Nautec has completed the structural repair of a breasting dolphin pile for a major Saudi Arabian asset owner in the Ju’aymah Field. Upon general visual inspection of the breasting dolphin, which was performed by a team of divers, it appeared the South leg pile of the structure had suffered damage resulting in the top and bottom half sections of the pile ending up misaligned.

The Scope

Engineering:

  • Analysis and Design of the structural repair of the pile.
  • Deliverables: Analysis and Design report, Strengthening methodology for pile.
  • Inspection of clamp fabrication.
  • All designs were fully verified by DNV Singapore.

Grouting:

  • Provision of grouting spread, grout material and accessories to perform the structural repair of the pile by grouting with NaX® ultra-high strength grout.
  • Provision of Lead Engineer and crew to perform the grouting work.
  • Provision of supervisors to oversee the local clamp fabrication.

The Challenges

  • Entire terminal including the breasting dolphin is extremely busy and of critical importance to the client.
  • Extreme loads had to be factored into the high strength grouted clamp solution resulting from the mega tankers berthing against the structure.

The Services

  • Detailed inspection support and data review to capture important information about the pile and the damage it had sustained.
  • Analysis and design of the structural repair of the pile; analysis and design reporting; and strengthening methodology for the pile.
  • Managing interface with DNV to verify the clamp design and engineering analysis.
  • Removal of marine growth from pile surface using ultra high pressure water jet.
  • Mobilisation of equipment and supply of specialist grouting material to offshore worksite.
  • Installation and sealing of clamp with divers’ assistance.
  • Structural repair of the pile by grouting pile and clamp with NaX® ultra-high strength grout. Nautec used its own small-footprint grouting spread and proprietary grout materials and accessories to carry out the services as well as its in-house engineering team and highly experienced crew.

Added Value

  • The repair works were carried out using NaX® Q140, which is a rapid strength development grout with high elastic modulus. About 40% of the design compressive strength and 75% of elastic modulus of the grout can be achieved within 24 hours. NaX® Q140 offers shorter installation time and earlier demobilisation saving offshore installation cost in return. Moreover, NaX® Q140 offers outstanding fatigue strength compared to conventional grout.
  • The unique ultra-high strength of NaX® Q140 endures up to 40,000 times more stress cycles than a conventional grout for the same stress range. NaX® Q140 is partially shrinkage compensated and has no shrinkage in a sealed condition. Due to its dense and stable microstructure, NaX® Q140 is highly impermeable to water.

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