Design of composite overwraps for pressure

Both of the aforementioned codes design the repair of pipes in the hoop and axial directions so that the original design pressure can be reinstated then select the stronger of the two as the design repair. 

In the axial direction, both codes design for an equivalent imaginary force that is supposed to induce similar overall stress in the system as all other loads and moments combined. ISO presents this equivalent force as 

Rehabilitation of Pipelines Using Fiber-reinforced Polymer (FRP) Composites 

When it comes to the hoop direction, ISO proposes Eqn (10.2) in order to calculate an equivalent pressure  

ASME s hoop design equation is only based on internal pressure. ASME ignores the contribution of other loads such as the shear force and the torsional moment in generating hoop stresses. As is seen, ISO is a rather more advanced code when it comes to the calculation of effective axial force and effective pressure. 

---