Minimum Hydrotest Bend Radius Analysis

Pull sections are typically hydrotested while they are still laid out on the ground, and in rough terrain the strung pipe conforms to whatever the ground gives it — side hills, ditch crossings, spoil piles, roll bends and sag bends far tighter than anything on the design profile. With the line pressurized well above operating pressure, the bending stress from that terrain-driven curvature stacks on top of an already elevated hoop stress.

This analysis returns the minimum bend radius the pull section can hold at test pressure before the combined stress reaches the code-permitted percentage of SMYS, so you can tell which bends along the string need to be regraded, cribbed, or relieved before the test is brought up to pressure.