Analytical Modeling in Support of Operational Decisions, Structural Repairs, or Field Modifications

Operation and Maintenance of lifeline structures must minimize closure downtime while insuring safe operation. Thus, anticipating component replacements, due to fatigue life for example, allows preventive maintenance to occur during scheduled outages where advanced planning minimizes transportation losses. Similarly, when structural repairs are needed, a balance between the time required for implementing the repair and the effectiveness of the repair for preventing reoccurrence is considered. Field modifications to structural components are sometimes needed so that maintenance can be more efficient. Evaluation for the effects of the structural modification are important to insure that the modification is effective and that it will not cause any other unintended problems. ANATECH, a Structural Integrity Associates company has performed finite element modeling in support of these operational and maintenance issues, such as remaining fatigue life, effectiveness of structural repairs, and evaluation of field modifications and design retrofits. In addition, we have investigated the effects of residual stress fields on the fatigue cracking at welded connections. These analyses involve coupled thermal stress analyses with nonlinear and temperature dependent material behavior and ductile crack propagation growing in residual stress fields.

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Fatigue Life Evaluation

  • Determine remaining fatigue life of components for operational logistics

  • Evaluate fatigue performance of embedded steel components

Evaluate Effectiveness of Structural Repairs

  • Repair of fatigue cracks at welded connections

  • Grouted pre-stressed bars or anchors for cracking control

Evaluate Structural Performance of Field Modifications

  • Modify components for maintenance requirements

  • Determine optimum bolt loads for pre-stressing requirements

  • Evaluate stress redistributions for optimal modification results

Evaluate and Verify Design Retrofits

  • New design requirements or life extensions

  • Upgrades to existing capabilities

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