The concrete mattress sizing and required spacing will be determined based on the following assessments:
- Mattress vertical edge stability check - to ensure mattress edge is not lifting due to vertical hydrodynamic loads;
- Mattress lateral self-stability check - to ensure mattress is not wash-offed due to lateral hydrodynamic loads;
- Pipeline pull-out check - to ensure there is no mattress dislodging from pipeline due to lateral active pipeline forces active on the mattress;
- Mattress and pipeline sliding together (system stability check) - to ensure mattress submerged weight is sufficient to prevent lateral movement of mattress and pipeline;
- Pipeline local buckling check - to ensure integrity of the pipeline located between the mattresses throughout design life (FE dynamic analysis will be required).