I have some queries related to using Sway Brace in Caesar ?

I am following a particular method to find the exact restraining force.

1. Run Modal Analysis and find the frequencies of vibration.
2. To put a sway brace at a particular node point so as to increase the harmonic, find out the displacement in that direction.
Total Displacement = Modes mass Normalized x Mass at that Node point (mm)
3. Displacement due to vibration = Total Disp - Disp. in OPER (W+P1+T1)
4. Acceleration = (Frequency (rad/sec))2 x (disp.due to vibration)
5. Force = Mass at that Node point x Acceleration.
6. Using this force as the maximum force (Fy "Yeild Load") and selecting the Spring stiffness from the vendor catalogue we can select the accurate sway brace required for the application.

Kindly comment on the following steps.
I would like to know if there is any other method to select a sway brace.

Can sway brace used in a line having 2 phase flow / Water Hammer ?
k_suraj1978@yahoo.co.in

You can't do it this way, since the modal analysis doesn't give you anything but frequencies. The mode shapes are normalized, and were developed assuming undamped free vibration. You have to apply a load to obtain reliable displacements.

I suggest you run the analysis with your real load, then size the sway brace according to the actual displacements you obtain.

Hello Richard,

I cannot put restraints at the Nodepoint as that will increase the Thermal load in the system.
If I dont have restraints at the nodepoint, then How do I get the restraining force?
The nodepoint should be free for thermal expansion and at the same time the frequency of vibration must be increased.

If I want to put a sway brace in X dirn.
Should I put a Rigid X at that Nodepoint, find the force. Then using the Thermal displacement without restraint find out the stiffness (K).....(F=kx) ?

Read the article on Modeling Sway Braces in this newsletter . This should give you all the information you need.

Hello Richard, i'm new in the forum, My name is Jose i'm from Spain, and i'm looking for information about how to model sway braces, but the link you show doesn't work. Please can you verify where is this newsletter now?, because i check that this topic is from 99. Thank you any way.

The news were found in COADE website, you mean you can't download it.

Try this link I get this paper in COADE website:

http://www.coade.com/Mechanical%20Engineering%20News.shtml