Subsea Structures Detailed Design

Key Assets
The continuing trend towards subsea developments places ever greater emphasis on the need for cost effective and practical subsea structures. These structures must support and protect critical piping and equipment for the life of the field, whilst providing easy diver/ROV access for critical intervention tasks. Reliable performance of these assets is critical to the success of a development, requiring great care and attention to detail in design.

Our comprehensive design service covers conceptual, FEED, preliminary and detailed engineering of all types of subsea structure, supported by our team of experienced subsea engineers. We work closely with client, installation contractor and fabricator throughout the project to ensure suitability of final design and compressed schedule.

Structure Types
Our design team has experience of all types of subsea structures in deep and shallow water, including Manifolds, Templates, SSIV protection, PLEM, Subsea Distribution Assemblies, Wellhead protection, Drill centers, Dynamic riser bases, Subsea PLR modules, PLET and in-line Wye/Tee assemblies.

Layout
Early use of modern 3D CAD tools to define layout of piping, valves, actuators, flanges, tie-ins and equipment. Size and weight optimised to suit installation vessel and fabrication facility. Designs tailored to suite diver or ROV IRM philosophies (tie-in, valve operation, equipment installation/retrieval).

Structural Analyses
State of the art structural design software is used to develop efficient structure designs in accordance with either limit state or permissible stress codes. Global analysis may cover/involve load-out, transportation, marine lifting and in-place analysis including hydrodynamic and earthquake loading. External loads from dropped object impact, trawl snag and pipeline tie-ins can be addressed. Piping assemblies adjoining spools and foundations can be included in the global structural analysis to capture critical interaction effects. We have experience in piping and fitting analysis and design to ASME B31.3,B31.8 etc.

Foundations
Our geotechnical specialists have wide experience in soil characterisation and subsequent design of piled, gravity or suction pile foundations. Rigorous seismic analysis and design can be provided when required. P-Y curve and limit equilibrium methods are backed up by sophisticated numerical modelling when appropriate.

Design Package Preparation
Our design team can provide preliminary, conceptual and detailed design drawings (2D and 3D), material take-off, weight take-off, specifications, design reports, procedures, philosophy documents and studies. Preliminary drawings and MTO are provided as early as possible to expedite procurement of long lead items.