Seek help and advise for open Half Skirt Design support for Vertical Vessel

Hi Blackpanic73,

Thank you very much for the information. My does Client does not agree to provide full skirt with full base plate that i proposed to him but because of the piping connection underneath he does not agreed please see below photo.

Thanks

Sorry for my language. im not good enough in english. what i mean mean to say is my client wont agree to provide with full skirt type of support for the vessel, because he dont want to change the design for concrete foundation.

Thnks for understanding.

This was already addressed in post 1 (GA), with this remark:

"that is very sample calculations for complete skirt without any cut.

you can calculate the ratio of cut from the skirt and then increase the thickness with the same ratio ( that for very quick calculations)"

Your simplified methods and assumptions are acceptable for this small diameter vessel with a limited foundation load. ( 711 mm diameter and 4000 kg)

However, I would not use your split skirt for any vessel greater than about 1500 mm diameter or any vessel subject to wind/seismic loading along the weak axis of the support skirt.

In that circumstance, a full skirt is the correct choice.

My opinion only

thanks mr Anonymous for your post

in my company we use full skirt if diameter larger than 1000 mm or height larger than 3000 mm. additional to using anchor bolt chair or lug ring for making my design more safety.

Hi everyone, Thank you very much for your suggestion and Idea.

The latest communication we had from my client is to make support calculation, considering buckling at worse condition for the thickness of the Skirt that i give to them. I run the calculation using PVELite to get the thickness of the skirt using opening type and considering a full length of opening on the skirt and my base plate i choose the square area of 550 is the same to the area of the full Base circle.

the calculated bucking in my design is for the full base ring only, I also suggested that this is more stronger compared to your Half Skirt type with half base plate but my client does not want to change their design because the foundation has already been made. I know the thickness that I've considered in the skirt and in my baseplate is enough to support buckling at worst condition, but proving it is somewhat difficult for me.

My Wind Pressure is 1531.25N/m^2 (User Defined) base on Client Specification

Overall Height = 3m

No Seismic.

I know that this is small vessel only, but they need me to prove that this is safe for buckling at worse condition.

Any Suggestion Please.

Thanks Very much

Dear yhinganetone

Greeting to you

after you do all calculations of skirt depending on wind load as specified by your client, you must check on buckling by calculating the actual deflection which can be ocuured on top of vessel as following:

1- calculate the actual deflection by using this equation

WHERE :

2- compare the actual deflection from above equation with the maximum allowable deflection on the vessel

Max. allowable deflection 6" per 100 ft of height

in your case the tota;l height is 3000 mm = 9.84 ft

so the maximum allowable deflection in your vessel is 15 mm = 0.59 in

3- Since the actual deflection from the above calculation does not exceed this limit of maximum allowable deflection , the designed thk. Of the skirt is satisfactory.

Hi blackpanic 73

Greeting to you

Thank you very much for your reply, Support Calc already submit to my client. Awaiting for his feedback.

Thank you very much once again for your idea.