Pipeline Buckling Design Course Program
September 8-9, 2008 • Houston, Texas
DAY ONE
8:00 Registration, coffee
8:30 Welcome and introduction
8:45 INTRODUCTION
- Basic concepts
- Field design examples
- Pipeline simulation animations
9:45 THERMAL EXPANSION
- Strain of pipeline under thermal load
- Stress of pipeline under thermal load
- Pipeline displacements and forces
- Expansion movement, anchor forces, flange loads and spool design
10:30 Coffee Break
10:45 LATERAL BUCKLING OF STRAIGHT LINE ON FLAT SEABED
- Equations for lateral buckling
- Values for the buckling constants
- Total expansion into the buckle
12:00 Lunch
1:00 UPHEAVAL BUCKLING THEORY
- Analysis of up-lifts
- Upheaval movements
- Maximum required download
- Interaction between lateral and upheaval buckling
2:00 Coffee
2:15 NONLINEAR FEM THEORY
- Description of the finite element model (Static analysis problems; Dynamic
analysis problems)
- Steps in an analysis and choice of analysis procedures (Static analysis
procedure; Dynamic analysis procedure)
- Element types used in the model
- Non-linearity and seabed model (Material model; Geometrical non-linearity; Boundary condition; Seabed model)
- Validation of the finite element model
3:15 CASE STUDY #1: LATERAL BUCKLING CALCULATION EXAMPLES
Example calculations will be performed by course attendees based on the methodology
given in Thermal Buckling of Pipelines Close to Restraints, R. E. Hobbs and F. Liang:
Eighth International Conference on Offshore Mechanics and Arctic Engineering (1989).
4:15 CASE STUDY #2: UPHEAVAL BUCKLING CALCULATION EXAMPLES
The upheaval buckling analysis and the required burial depth to prevent upheaval
buckling for the buried pipeline based on the paper presented by Palmer, Ellinas,
Richards and Guijt (OCT 6335, 1990). The paper presents a method to calculate the
required download force (Fd) based on different dimensionless imperfection length.
5:00 Close of Day One
DAY TWO
7:45 Coffee
8:00 SEABED AND SOIL MODELING
- Pipe penetration in Soil
- Soil axial friction coefficient
- Soil lateral friction coefficient
9:00 AXIAL STABILITY AND PIPELINE WALKING
- Main design parameters
- Flowline axial stability issues (Key features; Lateral Stability; Axial Stability)
- Finite element models
- Simple lateral stability calculations (Axial tension; Thermal loading; Stable vs
Unstable);
- Assessment of pipeline lateral stability.
9:45 Coffee Break
11:00 Coffee Break
11:15 GLOBAL BUCKLING DESIGN
- Dynamic buckling analysis
- Cyclic in-place behaviur during shutdown operations
- Pipeline on flat seabed (strength and fatigue check, pre-snaking; buckle
trigger)
- Pipeline on uneven seabed (Strength and fatigue check; seabed interventions)
- Burried pipeline & upheaval buckling prevention
12:00 Lunch
1:00 ACCEPTANCE CRITERIA
- Local buckling tests
- Local buckling analysis
- API 1111 & DNV OS F101
- Strain criteria
- Moment criteria
2:00 Coffee Break
2:15 LOCAL BUCKLING ANALYSIS
- Local buckling & collapse
- Mesh density
- Material
- Loads and load sequence
- Boundary conditions
- Ultimate strength interaction between pressure, axial force and moment
3:00 Coffee Break
3:15 RELIABILITY-BASED UPHEAVAL BUCKLING DESIGN
- Required burial depth to prevent upheaval buckling for the buried pipeline
- Random variables
- Limit-state function
- Failure probability calculations
- Reliability-based design of burial depth
4:15 CASE STUDY#3: MOMENT CRITERIA & STRAIN CRITERIA CALCULATIONS
- Calculation example for strain criteria
- Calculation example for moment criteria
- Comparison with stress criteria
5:00 Close of Course
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