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#39882 - 01/05/11 03:58 AM Stiffness & friction in CAESAR II
New_Stress_user Offline
Member

Registered: 01/05/11
Posts: 4
Loc: saudi arabia
Dear Members,

I'm new for CAESAR II and i'm doing stress analysis in CAESAR II.
I have some Queries.

1. Do we need model expansion joint as it is which we received the data from vendor ? or we just insert the Data as it is ??

Ex: Expansion joint typs is Hinged.

2. do we need to insert stiffness and friction values for Various Supports.

3. if yes. then can we assume stiffness values ?

please let me know....

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#39887 - 01/05/11 08:56 AM Re: Stiffness & friction in CAESAR II [Re: New_Stress_user]
stack_brr Offline
Member

Registered: 12/20/10
Posts: 6
Loc: middle east
Stiffness and friction have a significant effect on the outcome of the analysis results. Ideal anchors have infinite stiffnesses , but real anchors have different behavior. We might have used ideal anchors with infinite stiffnesses in analysis , which will yield higher stresses and forces , but might be in practical anchors dont have that must stiffness that we have used in our analysis .

So, we should try to simulate as close as possible the real world environment , although I agree that its difficult to get exact stiffnesses values of the real world supports , but we should try to evaluate it with good Engineering judgement.


Edited by stack_brr (01/05/11 09:00 AM)

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#39921 - 01/06/11 05:38 AM Re: Stiffness & friction in CAESAR II [Re: stack_brr]
Rajinder Singh Offline
Member

Registered: 07/25/06
Posts: 55
Loc: New Delhi
1. Hinged type expansion joint is modeled as zero length expansion joint. You need not have to model expansion joint as shown on drawing. Axial, transverse and torsional stiffness are considered as rigid. Only bending stiffness is mentioned which is bending stiffness of hinge. Refer CAESAR Applications Guide for expansion joint modeling.

2. Stiffness values: You can put if you have one. Friction values: Yes.

3. Assuming stiffness values at supports will alter your results (compared to results without mentioning stiffness values). Support stiffness values are usually kept blank because they are assumed as rigid in mathematical model. Being rigid it yields conservative results (high loads and stress). However, in real life it is not so. But calculating support stiffness values is a complex activity. You can contact civil/structural department for stiffness values (of supporting structure) if absolutely required.
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#39997 - 01/08/11 12:40 AM Re: Stiffness & friction in CAESAR II [Re: Rajinder Singh]
New_Stress_user Offline
Member

Registered: 01/05/11
Posts: 4
Loc: saudi arabia
Dear Stack and rajinder,

Thanx alot for your valuable Information.
I look forward for your help.
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New_Stress_user

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