...
P-Delta analysis has been a requirement in structural design codes for many years due to the importance of its effects on in design calculations. However, piping stress models have traditionally ignored P-Delta effects, possibly because most older generation piping stress software programs are incapable of P-Delta analysis.
...
Vertical displacements displayed below for weight case only (selfweight including fluid). Right-side window is weight case with consideration of P-delta with large displacements with max vertical displacement of -8.69". Left-side window are displacement results from the same weight case, but ignoring P-delta effects, with a calculated max vertical displacement of -41.5", which is what other legacy piping stress programs will report. With a long flexible pipeline like this, there is catenary behavior that needs to be accounted for in which axial load is being distributed to the anchors to help support the pipeline. P-delta with large displacements accounts for this catenary behavior which made quite a difference in this example..
