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#4211 - 11/22/05 12:57 AM Cold Pull in Expansion Joint - In Caesar II modelling
sam Offline
Member

Registered: 02/25/04
Posts: 643
Loc: Maharastra, India
In many bellow detail with yellow colored shipping bars, we find installation length of the bellow differing from manufacturing length of the same, due to bellow specification requirement of cold pull of 50% of calculated expansion. Where the minimum temperature T1 is much away from installation temperature T3, the required cold pull = 0.5 -(T3-T1)/(T2-T1) where T2 is the maximum temperature.

In Caesar-II modelling, do we consider this cold pull of bellow ? If so, do we consider 100% effect of the cold pull or 2/3rd & 4/3rd of the same in force/load calculation?

regards,

sam
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#4212 - 11/22/05 11:50 PM Re: Cold Pull in Expansion Joint - In Caesar II modelling
sam Offline
Member

Registered: 02/25/04
Posts: 643
Loc: Maharastra, India
"In Caesar-II modelling, do we consider this cold pull of bellow ? If so, do we consider 100% effect of the cold pull or 2/3rd & 4/3rd of the same in force/load calculation?"

Is this a 'consulting' question & nobody will address it for that reason ?

How on Earth did we get in here, such a lonely individualistic islands of our own? Is there any harm in sharing ?

I remember the writing of John(Fire) Lame Deer, an American Indian - "We had no locks nor keys and therefore among us there were no thieves. .. We didn't know any kind of money and consequently, the value of a human being was not determined by his wealth."

Let's go back to those good old days!

Mahatma Gandhi said 'Be the change you want to see in the world'. If Dalai Lama can wear Nat's Cap, we, too, can change!

regards,

sam
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#4213 - 11/23/05 01:41 AM Re: Cold Pull in Expansion Joint - In Caesar II modelling
anindya stress Offline
Member

Registered: 04/12/04
Posts: 493
Loc: London, UK
Sam,
I don't know about others. Personally I have not responded as I don't know the answer.

Regards
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anindya

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#4214 - 11/23/05 04:55 AM Re: Cold Pull in Expansion Joint - In Caesar II modelling
sam Offline
Member

Registered: 02/25/04
Posts: 643
Loc: Maharastra, India
Dear Anindya,

You are too serious; none expect any justification. We just talk as life is fun only to the people who think it so.

While reading newspaper I found some good points to share - may be someone, somewhere can benefit from it; so I wrote the same here.

Few months ago I was thinking deeply over a problem - a baul(village singer in Tagore's bengal) came & started singing - his theme was - be a begger, share your problem, solution will come to You direct! Now, you may ask, what was my problem at that moment; I was feeling that nobody understands.I understood, if I don't speak up, how can people understand !

regards,

sam
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#4215 - 11/23/05 07:32 AM Re: Cold Pull in Expansion Joint - In Caesar II modelling
John C. Luf Offline
Member

Registered: 03/25/02
Posts: 1110
Loc: U.S.A.
SAM,

Usually field fit up problems... are not incorporated into the final analysis model. The problem is one of time, money, and communication.

Time-usually your analysis must be complete prior to fabrication and errection.

Money-If you adjust for this misalignement what about the other 10 miliion tugs and pulls used to get the final fit up???? Do you try to keep track of them and then the ultimate question will they add up to much?

Communication-Usually my luck of getting feed back from the field forces is spotty at best.

Finally metallic expansion joints should be ordered with a field fit up allowance. If the fitup is above that alloted I would contact the manufacturer for their feed back.
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Best Regards,

John C. Luf

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#4216 - 11/23/05 07:52 AM Re: Cold Pull in Expansion Joint - In Caesar II modelling
Chuck Becht Offline
Member

Registered: 01/16/05
Posts: 51
Loc: USA
In my opinion, preset of an expansion joint is not equivalent to cold spring and therefore need not be considered in the manner cold spring is. I would model it, cosidering the specified preset, not 4/3 and 2/3 the values.
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Chuck Becht

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#4217 - 11/23/05 09:59 PM Re: Cold Pull in Expansion Joint - In Caesar II modelling
sam Offline
Member

Registered: 02/25/04
Posts: 643
Loc: Maharastra, India
Thanks to you both, Sirs.

I, also consider the specified cold preset, as written by Becht Sir, in the modelling. Luf Sir has misunderstood this cold preset with field fit up tolerance. I am assured that I am not alone in this regard.

My confusion was whether we can take full credit of it as per ASME B 31.3, as after all it is 'cold spring', whatever the name 'cold preset' we call it by.

regards,

sam
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