Evaluating Pipeline Spans



Pipeline operators are often unsure how to proceed in evaluating pipeline spans. They face the issues of either using outdated simple methods that can provide results are far too conservative on the lengths allowable in their pipe spans or they can miss things like continued erosion that will increase the length of the span and cause problems in the future.

Stress uses both analytical methods and finite element methods to evaluate pipeline spans. The benefit of the analytical methods is that they use relatively simple inputs and that they can be applied to a large number of spans on the same pipeline so that you can do one calculation to apply to a number spans. That way you can use it is a screening method to see which of your pipelines spans needs further evaluation.

Finite element methods, requires more detailed information about the shape of the pipeline so we need survey information for example, but they can provide much more accurate results that often allow you to use a span length much longer than those predicted by the analytical calculation.  The analytical calculations on the finite element results generally only give you a strength value of the pipeline for steady-state loading. Other things that you need to consider are hydrodynamic loads, the possibility of debris impact, and vortex induced vibration due to the water flowing across the pipe. Wind can also result in vibrations of your pipeline for certain spans and all that needs to be checked. There can also be other factors that you need to keep in mind when evaluating pipelines spans and we can assist the operators with determining what these factors are.