welded steel pipeline above ground thrust issues?
welded steel pipeline above ground thrust issues?
(OP)
I am a structural engineer and I have a question: I have a 24" diameter steel pipeline under about 40 feet of hydraulic head with occasional changes in direction of 45 degrees each. The pipes are welded together using groove welds. Do I need to account for thrust forces at the bends even though the pipe has welded joints? The pipe run is close to the ground and is supported by pre-cast concrete planks.
RE: welded steel pipeline above ground thrust issues?
It boils down to, no large thrust restraints are required (to keep the elbows attached to the pipe), but you must design the pipe for hoop stress and axial tension, or maybe compression, if movement is not possible due to high Friction. If you allow movement, compressive pipe axial wall stresses reduce and stresses shift towards and may cross into tension caused by the elbow loads again. So as long as the pipe is designed for both hoop stress and whatever axial tension or compression stress remains, or the range of those stresses, no problem, as long as the movement is not excessive.
RE: welded steel pipeline above ground thrust issues?
In general no you don't need elbow restraints on welded pipes. However you do need to allow the pipe to move, however small an amount, so often need to guide the pipe to stop it moving all over the place.
A lay out drawing would be good to see.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.