Pipe Anchor Force

[amec2004]

Hi, All

I am a structural engineer and from time to time I have to design structural support (concrete pedestal, steel, piling etc) for pipe anchors. We are mainly doing mining project and there are pipe anchors surrounding pump house to carry the pipe's thrust force before these 30" pipes connecting to 3500HP pump suction/discharge nozzles. I have a couple questions

1. There are different pressure in the pipe, operating, test, etc. Someone says transient pressure to be 20% higher of operating pressure. Someone says we have to use rupture disk fail pressure which is quite high compared to 1.2 of operating. In terms of structural support design, which pressure shall be used to work out the transient anchor force ?

2. Someone says the worst scenario for structural load case is
1) the rupture disk fail pressure multuply pipe section area to get the transient force

2) There is a transient force acts towards the pump, meanwhile there is another acting on anchor support in the opposite direction. These two transient forces tear the pipe in between apart and we have to control the relative displacement between anchor and nozzle to be less than 5mm. Is this the case ? Can we ignore this case if there are vitalics in between ?

3. Is there any stress analysis reference for structural engineer? I don't want to be a stress engineer but just want to know how the transient force is generated and which load case is the worst and shall be considered in structural design.

Thanks

 

[BigInch]

It seems you are asking about forces generated from several different load cases, but do not ask anything about what can easily be the largest one of all; from the thermal case.

You should have a thermal analysis and a transient hydraulic analysis for each pipe showing the calculation and placements of these and any other significant loads, seismic, wind, currents, snow & ice, vehicles, soil forces, etc.

You must review all the loads on the piping to determine the worst case or worst combined cases for the structure or anchor to which the pipes are attached.

1. Thermal Forces from temperature expansion or contraction
2. Operating Pressure Forces
tension (pipe contraction)
pressure stress * Poisson's ratio
3. Relief Loads
load opposite disk or relief valve.
4. Transient Hydraulic Thrusts
See transient hydraulic analysis
can be +50% of operating pressure


BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com