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D12.A.2.7 Code Checking According to NPD

The following parts of Chapter 3 in the NPD guidelines have been implemented.

  1. Control of nominal stresses. (NPD 3.1.2).
  2. Buckling of pipe members in braced frames, including interaction with local shell buckling (NPD 3.2.2, 3.2.3).
  3. Buckling of un-stiffened closed cylindrical shells, including interaction with overall column buckling (NPD 3.4.4, 3.4.6, 3.4.7 and 3.4.9).
  4. Joint capacity check for gap as well as for overlap joints (NPD 3.5.2).

Check b) provides the unity check based on the beam-column buckling interaction formulae in NPD 3.2.2. The interaction between global and local buckling due to axial load and hydrostatic pressure is accounted for through computation of an axial characteristic capacity to replace the yield stress inn the beam-column buckling formulae.

Note: Check b) handles members subjected to axial loads, bending moments and hydrostatic pressure. In other words, check b) assumes that stresses resulting from shear and torsion are of minor importance, e.g., in jacket braces.

Check c) provides the unity check based on the stability requirement for un-stiffened cylindrical shells subjected to axial compression or tension, bending, circumferential compression or tension, torsion or shear. The unity check refers to the interaction formulae in NPD The stability requirement is given in NPD 3.4.7.