Mechanical and structural integrity

Advanced methods that assess the integrity, performance and life of your plant, structures and mechanical systems.

The efficient and safe operation of structures and equipment such as pressure vessels, offshore platforms and pipelines is vital for their continued profitable operation. Ageing assets, life extension and an ever greater focus on essential safety requirements mean that the level of effort required to deliver cost-effective, safe operation and to avoid costly downtime is increasing.

Frazer-Nash is at the forefront of the application of advanced techniques to the complex engineering problems experienced by a range of different material types, including metallic and non-metallic. These advanced methods can be used to assess the integrity, performance and future life of plant, structures and mechanical systems with confidence. 

Structural and mechanical integrity assessment

Structural and mechanical integrity assessment is fundamental to the safe and economic operation of plant, equipment and systems, and draws upon an understanding of structural loads, the local stress environment and materials’ behaviour. Most assets are subject to through-life degradation, with environmental and operating conditions promoting progressive damage such as corrosion or fatigue cracking. We have extensive experience of delivering comprehensive structural and mechanical integrity assessments and advice to clients, both in support of new design projects and to provide assurance for existing plant.

Assessment techniques

Our professionally-qualified staff deliver mechanical and structural integrity analysis techniques including:

  • Classical stress analysis
  • Finite element stress analysis
  • Fracture mechanics – API 579, R6 BS7910
  • Engineering critical assessment (ECA)
  • Weld residual stress modelling
  • Structural reliability analysis
  • Probabilistic assessments
  • Fatigue
  • Creep/creep fatigue
  • Non-linear analysis – material, geometry, contact
  • Heat transfer
  • Fluid structure interaction
  • Impact, blast and shock.


With a proven track record of providing structural and mechanical integrity justification across multiple highly regulated industries, we help the oil and gas industry to assure the efficient and safe operation of its assets, through:

  • Structural integrity assessment of pressure vessels and piping
  • Modelling of welding and other thermal processes for residual stress prediction
  • Assessment of ship impact on offshore structures
  • Examination of the effect of transient temperatures on process plant
  • Investigation and rectification of structural and mechanical failures
  • Fracture mechanics assessment of welded pipes subject to reeling/unreeling
  • Materials research
  • Integrity assessment of high temperature systems
  • Prediction of blast effects on structures
  • Feasibility and concept evaluation studies for novel structures
  • Life extension activities for deteriorating structures
  • Serviceability assessment for damaged structures
  • Design of plant modification programmes to improve performance and safety.