Tanmoy,
I am talking of checking formula for indentation because of tightening of clamp against thin walled pipes not the whether it affects or notother than design procedure & normal pressue values,And the formulas which I am having for calculating bearing stresses & indentation of pipe at support pipe are listed below .
1)Bearing stresses at the point of support.
Sb = 1.1 WL/DB
where, B=Bearing width (inches)
D=Bearing length (inches) I am values for this pl. let me know pipe size.
W=Weight of pipe (pounds/ft)
L= Length of span (ft)
Sb=Allowable code bearing stress (pound/inch2)(1.6 times value
from table A-1/2)
2) INDENTATION OF PIPE AT SUPPORT POINT
Stress in the shell of a pipe under local loadin.
S=1.17 F SQ. ROOT (RT) / T 2
where F=1.1 WL/2(D+B) LOAD/IN. due to radial thrust (poun/inch)
R = radius of pipe(in.)
T=corroded thickness of pipe (in)
B=Bearing width (inches)
D=Bearing length (inches)
W=Weight of pipe (pounds/ft)
L= Length of span (ft)
S = Sh for local loading on shoes. (all hot stress 31.3)
(pound/inch2) & 0.67 Sh for local loading on bare pipes.
But I do not know the source /literarture of the above formula, Can anybody verify this formula & its source?
Regards,
Rajesh Balapure,
Rajesh V Balapure
"Saha, Tanmoy"
<TSaha@mcdermott. To:
<PipingDesign@yahoogroups.com>
com> cc: (bcc: Rajesh V
Balapure/JAMNAGAR/RIL)
Sent by: Subject: RE: [PipingDesign]
Design of clamp support.
PipingDesign@yaho Importance: Normal Sender's OU:
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06/20/2005 09:35
AM
Please respond to
PipingDesign
Rajesh
Clamped type shoe supports are used to facilitate support installations. Very easy to install and very easy to modify lots of flexibility. Pipes can be hydrotested at much earlier stage as no welding in pipe due to supports. You did not require waiting for full installation of supports and all.
Next this clamp pressure will act opposite to the line inside pressure. Hence do not think it affects pipe thickness calculations anyway.
In some countries where it rains too much like Holland they prefer everything galvanized. In that case this is an excellent choice with galvanized clamp shoe. Again if pipes are CS and other exotic materials, CS shoes can be used with proper isolations between the clamp and the pipe.
Design procedure should be welded shoe type with pad.
Tanmoy Saha
Senior Mechanical Engineer
McDermott, Dubai
++971 4 8043132
-----Original Message-----
From: PipingDesign@yahoogroups.com [mailto:PipingDesign@yahoogroups.com]
On Behalf Of Rajesh.Balapure@ril.com
Sent: Monday, June 20, 2005 7:45 AM
To: pipingdesign@yahoogroups.com
Subject: [PipingDesign] Design of clamp support.
Dear Piping Design group members,
If anybody knows ,can you tell me how to get info. for following :--->
My Queery is:->
2)Could any body suggest the design procedure for the same also.?
3)How to calculate Bearing stresses at the point of
support?---->(manual
calculation)
4)How to find INDENTATION OF PIPE AT SUPPORT POINT ?-------->(manual calculation)
(i.e.Stress in the shell of a pipe under local loading.)
This is to clarify that the pressure mentioned is the bearing
pressure
on the pipe surface due to tightening of clamps . For design of the
clamps
this is critical as higher pressure could indent the pipe and in some
large dia. thin walled pipe there could be local buckling also.
Regards,
Rajesh V Balapure
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[Non-text portions of this message have been removed] Received on Mon Jun 20 00:27:00 2005
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