Median rotational values for welded pipe joints corresponding to: yielding, rupture, leakage

[teadjr]

Hi,

I am working on my MSc thesis studying the seismic performance of a typical industrial structure, a steel piperack, which supports not only piping but also cable trays and numerous Air Coolers on its top level. This piece of equipment has piping attached to it (the inlet and outlet header piping).

Among the types of piping connections/joints, there are welded elbows, tee connections, welded neck flange connections, branch lines welded on fittings to main lines, nozzles. The diameters of the pipes and fittings, we are dealing with, are: 4", 6", 8", 10", 12", 16", 20". All pipes are made of steel and have standard schedule.

I was wondering if you had any data (numerical or experimental test, or even code) about limiting values for welded joint rotations in respect to these damage states: yielding, rupture, leakge. Whichever occurs first.

Since I will have to reference this data, if possible, please tell me the source where you got those values.

Thanks in advance!

 

[Duwe6]

Per the engineering standards/Codes I am familiar with, the values are the same as the pipe. In reality, the welds are a little stronger, and thus stiffer than the pipe; so what? There is feet & feet of pipe on either side of the weld [up to 40-ft both ways], and the weld is about 1/8-inch thick on the ID and about 2 to 3 pipe-thicknesses wide on the OD. Makes the weld size trivial, and coincidentally it provides crack/tear arresting ability. Those nasty things generally stop at a weld.

 

[BigInch]

A general 2% maximum strain limit is common.