Calculation for bearing capacity of several spiral welded steel tubes

The bearing capacity of several spiral welded steel tubes can bear is related to the material, wall thickness and diameter.

Pressure calculation formula of spiral welded steel tubes:

Pressure = (wall thickness * 2 * steel material tensile strength) / (outer diameter * coefficient)

Spiral pipe steel pressure coefficient: 
Pressure P<7Mpa, Coefficient S=8 
7<Pressure P<17.5, Coefficient S=6 
Pressure P>17.5, Coefficient S=4