What can reduce capacity of a pipe supports 3

[shrikan]

Hi
We are in process of increasing / checking loads in our PS standard.before we proceed any further ,I was intrested in knowing what can cause reduction in load capacity of steel pipe supports( like clamps / shoes etc etc).SOme of the examples i can think of are bolts,connected steel thickness for welded PS.

Thank you in advance.

 

[pennpiper]

The question: "what can cause reduction in load capacity of steel pipe supports"

One answer is: "Temperature", Extreme Heat or Extreme Cold, both can result in a reduction in load capability.

Sometimes its possible to do all the right things and still get bad results

 

[bimr]

Corrosion may also reduce the load capacity of steel pipe supports.

 

[mk3223]

May be the change of the design rules or local Regulations which are to increase of the design loads, such as Building Code, seismic or wind loads, etc.

 

[shrikan]

thank you...i was more looking for material properties or welding details...like type of welding etc

 

[IFRs]

Holes and welds can affect strength by reducing critical cross sectional area or reduced strength in heat affected zones. Corrosion is a big one.
Pipe supports are usually robust and not designed down to the last pound or foot-pound, etc. The height of the post, eccentricity of the load, combination of loads (gravity loads, friction and gravity loads from thermal expansion, wind, seismic, ice loads, insulation loads, foundation settlement, impact loads from water hammer, dynamic loads from change of direction, etc) all play roles.

 

[AGazo]

Shrikan,
1. you need to find the weakest part of PS.
2. determine the operating conditions of the pipeline.
3. As per application of pipeline and PS, you need to calculate/check the weakest part for the required load.
Be informed that the design of PS should not be universal for all the loads listed above. Only in this case the PS will be technological, economical.
At the end you will get several designs for one type of PS for different operating conditions of pipeline.

 

[racookpe1978]

Now, be very, very aware of the "other half" of the pipe support failure (by corrosive or bad maintenance or bad inspections).

If ANY spring balanced or spring compensated pipe support jams up, is stuck by rust or dirt or crud or physical damage (being hit or struck by a crane or other part), then that pipe support AND ALL OTHER pipe supports in that string may become overloaded at the next temperature change. The "jam" could be at the cold point - then the pipe heat up and the pipe is overstressed. Or it jams up at the operating point, then the pipe is overstressed and causing other pipe supports to fail when it cools down or is drained to zero static loads.

Notice too that the pipe support jammed up or stuck inposition, but may not have actually "failed" and fell down from the structural steel holding it up. It is the pipe though that can no longer move and flex, and so pipe is overstressed or the nozzle the pipe is connected to is overstressed.