Deflection in Plant Structure

[ak1965]

One of the metallic structure approx. 50 mtrs. high, around the plant process equipment vibrates too much. We have doubt that deflection/ vibration is higher than normal & could be dangerous.

What could be the probable reasons ?

Any method to measure the deflection ?

How much deflection is allowed as per the code?

Which code is guiding factor for deflection in plant structure?


Forum may please respond or give suitable reference ...!

Thanks...!

 

[MikeHalloran]

Who are "We"?
Where are "We"?


Mike Halloran
Pembroke Pines, FL, USA

 

[ak1965]

@ Mike Halloran,

Thanks for your attention ... "We" are Human Technocrats & "We" live on "The Earth" currently.

I would appreciate if you could help to throw light on the techncial issue mentioed & request not to read between the lines..!

 

[desertfox]

Hi ak1965

If I have a structure that vibrates to much and its 50m high can you tell me why that is or would you like some more information so you can give a proper answer.

 

[ak1965]

As a thumb rule of civil engineering, the maximum allowable defelction for wind design shall be 1 horizontal per 200 vertical.

Soon, I shall be trying an innovative method to measure the defelction in our 80 mtr. high steel structure. let me suceed , i will share

 

[metengr]

Instrument the structure using a several strain gages if you have a concern about deflection and measure the frequency of the structure using prox probes. Hire a consulting structural engineer to evaluate the deflection data from the strain gages and hire a consulting equipment vibration specialist to evaluate the prox probe data.

 

[EdStainless]

What is the driving force making it vibrate?
Obviously it is not stiff enough.
But the real question is, Is it a problem?
Tell us why it matters.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[msquared48]

Obviously there is a driving frequency that is exciting the natural frequency of the tower.

Find out what the driving frequency is, then change the natural frequency of the tower to be out of sync with that and the vibration will cease. Changing the mass distribution will do that.

Also, you really need to anayze what several of the natural frequencies are here.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[MikeHalloran]

>>>
How much deflection is allowed as per the code?
Which code is guiding factor for deflection in plant structure?
<<<<
Ask your AHJ. We can't know which code applies absent spatial resolution considerably finer than one Earth.


Before you go fixing the structure, consider the possibility that the plant designer intended for an unusually large structural response to wake up the Human Technocrats so they would check for problems in the supported process equipment.





Mike Halloran
Pembroke Pines, FL, USA