Bending and curving of Krah Pipes
The high flexibility is already very known for Krah-Pipes, and a basic reference for the bending is given by R=50 x DN/ID for long term and even R=25 x DN/ID for short term.
So technically these two cases have to be diveded, in long and short term examination. The long term is to reduce fittings (bends) and the shirt term aspect is during the installation e.G. using the S-sinking method in water applicaitons, relining. What is a easy way to make a detailed calculation, to be sure that the pipe will not fail. How to calculate the minimum bending radius for a Krah-Pipe with profiled wall structure, in helical style?
Photo 1: Short-term bending conditions, the welding was done |
Rmin = α x DN [mm] Rmin = minimum bend radius [mm]α = bend ratio [-]DN/ID = Nominal pipe diameter, here inside pipe diameter [mm] The minimum bend radius is defined as the smallest radius to which the pipe may be safely curved. A maximum of total strain elongation should not exceed: |