2-150 Ton OH Crane Supporting Structure 1

[RHT2020]

Hi, I am desiging a building with 2-150 Ton overhead cranes and 3 ton jib crane. Columns spaced at 6.1m, crane bridge spans at 25m, roof is 20 m height and oH crane located at 11 m height.It is my first time to design crane supporting structures for this kind of monster crane I have following questions:

1) 2-150 T cranes are heavy, I am going to design the supporting structure with double column and braces between columns. I intend to put runway beam on the top of inside column. please advise if there is any advantage to put runway beam on a beam in between columns, I saw this details in my office by other engineers.

2) Double column spaced at 1.5m. there are huge uplift force due to crane side-thrust. Let's assume foundation can not take the uplift forces easily , I need to consider roof truss to roof column rigid moment frame, do you think it is a good idea?

3) As stated in (2), if I design roof truss to column as moment frame in each bay, do you think it is a good idea to add some roof horizontal brace to tie adjacent bays together.

Thanks,

 

[lexeng18]

Are these cranes to be designed for tandem lifts? Regardless, your side thrust and tractive design forces are going to be huge.

1.) Not sure if i follow, a sketch may help.

2.) Indeed this is a good idea, also probably a good idea to fix the main bldg column bases (not the crane columns). Even if every bent is a moment frame, without fixed bases you will have trouble controlling drift (I assume this bldg has some appreciable height to it).

3.) In my opinion you certainly will want to design horizontal roof x-bracing to facilitate load sharing between bents. For cranes this large I would not rely on a steel deck diaphragm alone.

I recommend finding a copy and reading AISE Technical Report 13 in its entirety. Lots of useful information for large crane design.

 

[ajh1]

Second the idea about using fixed base conditions, otherwise if you need any real tolerance on side movement, i.e., things like stacker cranes, you will never get there.
If you interconnect the crane column to the main column in a rigid fashion (effectively make it a single deep column) then your whole assembly can take your uplift (or really rotation) from your side thrusts within a single base connection. Interconnection of multiple frames at the roof will allow distribution of those side thrusts to multiple column bases. You generally can't count on more than about 3 frames taking any particular side thrust regardless of how many frames are tied together with the roof bracing. With three you would probably get about 60% of the load in the center frame (the original load point) and 20% or so in each of the side frames. Obviously if the crane moves one bay over those percentages also move over one bay.
Item 1) The only real time it makes sense to do the beam between columns trick would be at an interior location where there is a crane on each side of the column. In that case it is probably more likely that each runway beam would sit on top of its respective column, then a stub post up to the roof would sit on that beam that you describe. Generally you want as stiff of a base for the runway as you can get so positioning at some distance away from the supporting column on a beam is not ideal.

 

[FLCraneBuilder]

1) Insure you have ALL data on cranes being installed.
Tandem Lifts?
If so distance apart?
Wheel loads?
hoist weight?
Wheel spacing?
Proper Impact factors?
Class of service & duty cycle
Motion speeds
Rail size
end stop force? (Crane speed affect this)
and longitudinal restraint is controlled by end stop force
The building "might" be able to assist with lateral force - but this composite design effort is a complex task and needs to be done by folks who have done this before
make sure travel limit switches are used (bridge & trolley)
I assume indoor - but if outdoor - a wind loads come into play
The Crane builder can likely either do all this Runway design or give you good starting points
I would not begin this design process without knowing all of the factors noted above

In answer to your specific question - I would hedge towards solder column approach (runway beam on top of interior column) - but you might have very wide space between cols - to control lateral forces