crane loads
crane loads
(OP)
We have a client that wants us to make a last minute change and add a 40 ton crane with a 40'-0" span to a building that has foundations being poured next week. Does anyone know where I can get the loading information?






RE: crane loads
But better yet, convince the client not to do it, at the risk of severely delaying construction.
It's likely that just about every major structural component could require modification, including the foundations.
tg
RE: crane loads
Check out AISC for crane impact factors vertically and horizontally.
RE: crane loads
RE: crane loads
Your job as a consultant is not only to crunch the numbers but to also make the client aware of the implications of their decisions.
That said, is is pretty easy to estimate the maximum reaction from a 40 ton gantry crane, it will be somewhere in the realm of ... 40 ton. maybe add 20% for contingencies and redesign the foundations accordingly (if necessary).
The problem will be with the anchor bolts as you may need additional ones for the crane supports.
throughout the whole process keep the client informed of what you are doing and the implications so they dont come pointing the finger at you later when changes are required.
RE: crane loads
RE: crane loads
RE: crane loads
RE: crane loads
very late for adding major elements. Stop the foundation placement till loading and design changes are known.
RE: crane loads
If you guess wrong, the fix will be a nightmare.
RE: crane loads
Having done crane runway and frame design, let me tell you there is a lot more than meets the eye. And I agree with others, any crane mfr worth their wait in salt can give you lots of safe, conservative prelim numbers. A lot of them have software for this and actually pretend to do engineering, so beware of that. Probably little harm like others suggested in adding a 25%-50% or more safety factor to their numbers.
40 ton may have a large impact on your lateral loading from start/stop forces, and obvious effects on your gravity loading if you plan on using the building structure and not using separate runway columns...
RE: crane loads
engphila
RE: crane loads
RE: crane loads
Unless you want to make a conservative adjustment, the best way is to retrofit the crane structure within the building. Provide additional columns between the building columns. use a horizontal truss between the building columns to provide lateral support for the crane columns. The building framing then has to handle the horizontal loads which, are easily estimated.
"Conservative" adjustments are difficult when you don't know the details, how much moment to put into the column? should double columns be used? etc.
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: crane loads
Let's assume the gantry crane spans between steel columns (no rails). Then for a 40T crane I think best not to use the building structure columns but instead to provide separate columns for the crane. The crane columns may be tied back to the building columns. This means that you need foundations for the crane columns at perhaps 6m spacing, if you are going to tie back to the building coulumns those foundations will need to be enlarged to take both columns.
On a previous project we provided a gantry crane (this was a box beam girder type) with 1 x 30T hook and 1 x 10T hook. So I think we can assume equivalent to 40T. The span however was 25m.
The gantry carriages (one at each end of the gantry girder) had 2 wheels each. So total 4 wheels each with a max reaction of 225KN approx total =90T. But for the columne and foundation loads you also have to add the runway beams.
The runway beams have to be designed to fairly stringent deflection requirements. Depending on the code it could be span/500 or span/600, so large sections.
RE: crane loads
RE: crane loads
The OP didn't mention a Gantry did he?
Was the building designed for other cranes and they just want to add another 40 Ton crane?
If so, this might not be as bad as you would think.
Sometimes it is only a matter of adding bumper extensions between cranes to keep the cranes from loading the same areas.
Information on crane weights and wheel loads can be found in the Whiting Crane Handbook.