Overhead crane lateral loads

[ASFI]

Hi all

I am designing overhead cranes single and double girder.
For the lateral loads on the girders due to the crane accelerating or decelerating in the long travel direction, should we take the girder to be rigidally or simply supported to the end carriages? or maybe partially rigid but i dont know how to calculate this one?

This goes as well for buffer forces, wind effect for outdoor cranes etc...

I think choosing the right one has a major effect on the stresses especially when you have drives on all the end carriage wheels

Thanks for your help

 

[apsix]

You've lost me, what do you mean by 'carriage'?

 

[hokie66]

ASFI,
The ends of bridge crane girders are assumed to be pinned for both lateral and vertical loads. The carriages are not designed to impose weak axis moments on the runway beams.

apsix,
The carriage is the part of the crane with wheels which sit on the runway beam.

 

[apsix]

Thanks
I understand now, ASFI is enquiring about the crane bridge girder, not the runway girder as I assumed.

 

[ASFI]

Thanks hokie66

one more question, do you happen to know of any references that deal in detail with girder design of overhead travelling cranes (made of welded plates)? something that covers welding, fatigue, torsion, warping...

It is just very hard to find any material related to this subject.

ie: for a single girder crane where the hoist is running on the bottom flange, should I combine: shear stess due to bending + direct wheel load + tensile stress due to longitudinal and lateral loads + torsion + warping...

Thanks

 

[hokie66]

ASFI,
Yours is a good question, and I sympathise. As I think you are in Australia, there is a crane code which applies, AS1418. However, this is not a design guide, and actual design references are generally proprietary, tightly held documents by the major crane manufacturers or their consultants. I have never tried to design a crane myself. Perhaps you will get a response from someone in the business.

 

[apsix]

Some of the guidance for runway girders and monorails in AS1418.18 may be of use. That deals with stress combinations and torsion.
Fatigue checks can be done on accordance with AS4100 (my preference) or AS3990.

Having said that, I wouldn't attempt to design an overhead crane from scratch.