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RE: Pipe racks

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further,
pipe rack structure should be bolted connection.
 
and pipe/wall thickness will be design by piping engineer (mechanical),
piping will allow expansion loops  and all possible load combination such
as. 
pressure+thermal+wind on pipe.
piping should provide you supporting span, bottom elevation of pipe , loads
at each supports to design pipe rack structure.
supporting  types are as follows usually:
resting (piping loads >axial , vertical if wind consider lateral forced will
be)
guided ( piping loads> lateral, vertical)
anchor ( axial , vertical, lateral force (moments if any based how piping
consider in analysis) ).
PIPING designer will use following software to design pipeline
TRIFLEX or CAESAR 2.0 from this piping will give us support reactions and
span.


SHAHEEBUDDIN. MD
LEAD CIVIL/STRUCTURAL ENGG.
NPCC ENGINEERING PLC
ABU DHABI, UAE
EMAIL:shaheebm(--nospam--at)npcc.co.ae
FAX:+9712-5549111
TEL:+9712-5022104

> -----Original Message-----
> From:	Sherman, William [SMTP:ShermanWC(--nospam--at)cdm.com]
> Sent:	Friday, October 05, 2001 11:18 PM
> To:	'seaint(--nospam--at)seaint.org'
> Subject:	RE: Pipe racks
> 
> The forces on the structure due to piping depend on the details of the
> pipe
> joints, the layout of the piping, internal pipe pressure, and on the
> arrangement of the pipe supports. If the pipe joints are all restrained
> (i.e. can transfer axial tension) and the supports do not restrain axial
> movement, then there should be no need to resist static pipe thrust at
> bends. But if there are unrestrained joints (e.g., pipe expansion joints,
> couplings, etc), then the internal pressure will cause unbalanced thrust
> at
> bends (or valves). (An easy way to look at pipe thrust due to internal
> pressure is to draw force vectors along the axis of the pipe pointing
> towards each bend. With restrained joints, the forces at each end of a
> straight length of pipe will balance and will be resisted by tension in
> the
> pipe wall. But if the pipe tension is broken due to an unrestrained joint,
> then the force vector becomes unbalanced and must be externally
> restrained.)
> 
> 
> Pipes with restrained joints should be provided with "pipe guides" to
> laterally and/or vertically support the pipe periodically against movement
> due to wind or seismic, but generally should not be axially restrained.
> However, a single axial restraint near the center of a long run may be a
> good idea to prevent longitudinal movement, but you should make sure the
> bends can move freely to prevent restraint relative to the axial anchor.
> Axial friction forces should be considered due to longitudinal thermal
> movement or axial strain. Thermal movement causes very high forces if you
> attempt to restrain axial movement but only frictional forces if the pipe
> is
> free to expand axially. Friction coefficients for steel on steel can be
> 0.5
> to 0.7; Teflon bearings can reduce friction to 0.04 to 0.10. 
> 
> If you have structural beams between supports, I would recommend providing
> slotted holes at one end support to allow thermal movement. 
> 
> 
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