lifting plan for prewelded umbrella tank roof

[Eman1]

Hello,

Does anybody know or have info about lifting a pre-welded semi-spherical (umbrella) roof onto a tank wall.
I am looking for a lift plan, lug placement, required reinforcement info or the like.

Please share

Thanks,

Eman

[Eman1]

Added note - looking for info on large tank size 30 - 50 feet diameter or similiar

[lgwsaw]

If you are asking---- Does anyone out there have a lift plan to lift my umbrella style roof onto my storage tank?
The correct answer should be no.
You will need to have an engineered lift plan just for this particular lift.
A known set of accurate drawings will show you the roof thickness.
If this is a normal roof built in the last 50 years under good practice the weight should be about
32,200 lbs
Dish Crown
R/D Radius K1 Thickness Weight HT Arc Area
(ft) (ft) (ft) (ft^2)
1 50.00 0.8418 0.3750 32198 6.70 52.3 2104.48

This weight assumes there were no other loads designed into the roof.
Also this weight is only the roof plate itself.
If my drawing did indeed show that this roof was .375” in thickness. I would use 40,000 lbs. to be safe.
I have lifted many roofs like this and my experience tells me that 6 lifting lugs equally spaced about
1/3rd of the way up from the top angle or compression ring should be in the ball park.
Attach your rigging: six (6) 30’ foot long ¾” steel chokers with 7/8” s****les.
Get your gas ax out (cutting torch) and start ****ing away.

PS---- I just re-read the post and see you are installing a roof rather than removing a old one.
The same information would apply.
Is this roof being built inside the tank? If yes, you may think about air raising it instead.
If it's sitting out on the ground, than a crane lift is your only choice.

Good Luck,
LGW

[Eman1]

Hello Igwsaw,

Thanks for the info. Do you have any recommendation regarding books, codes or literature that i could look up in order
to supply engineering proofs on the lift lug position. Especially sag and allowable deformation at the tie in points (lift lug position).
Any rule of thumb info that you could share.

Thanks,

Eman

[lgwsaw]

You may have a look at this book by Bob Long--- I have not looked at it in about 10 years but its worth a look anyway.

[link Point to another website Only the registered members can access] This would be for your structural engineers to calculate out. Most of the crane companies will also provide lifting calculations.
I will also add--- I my experience (30 years) , we started out by trial and error years ago and have learned that- that’s the way this round hunk of steel needs to be lifted. Though years and years of practice.
I will always have some lifting lugs and chains close by just in case we need to address a low spot or if something is not quite hanging right or maybe out of level.
A good structural engineer will be your best friend------
Cheers
LGW

[lgwsaw]

You may have a look at this book by Bob Long--- I have not looked at it in about 10 years but its worth a look anyway.

[link Point to another website Only the registered members can access] This would be for your structural engineers to calculate out. Most of the crane companies will also provide lifting calculations.
I will also add--- I my experience (30 years) , we started out by trial and error years ago and have learned that- that’s the way this round hunk of steel needs to be lifted. Though years and years of practice.
I will always have some lifting lugs and chains close by just in case we need to address a low spot or if something is not quite hanging right or maybe out of level.
A good structural engineer will be your best friend------
Cheers
LGW

[Eman1]

Thanks for the info.

Much appreciated. Wondering if there is code reference that deals with heavy lifting of large structures. Maybe somebody knows.

Thanks again

[Eman1]

Thanks for the info.

Much appreciated. Wondering if there is code reference that deals with heavy lifting of large structures. Maybe somebody knows.

Thanks again