Overhead Crane Columns

[pioneer09]

Wondering if there is any publicaitons or data on when to use seperate crane columns vs attaching crane runway beams to the main building frame columns. I have a 40' tall building with (2) 30 ton cranes with possible expansion. I would gladly do prelim. engineering work on this, however this isn't in our budget and would stray from preliminary plans that were presented.

 

[SteelPE]

I went through this with one of my projects about a month ago. I had a similar questions is this thread similar to the one that you asked:

http://www.eng-tips.com/viewthread.cfm?qid=340535

Now, you don't say whether or not you plan to attach to the existing columns using brackets, or if your are trying to fabricate a stepped column or if you are trying tor frame the system completely independent from the structure. I have never done a crane that large, I would definitely not use brackets, I would probably use a separate crane column.

Some good information can be found in AISC DG 7.

Hope this helps.

 

[DaveAtkins]

I believe the rule of thumb is use separate columns for 20 ton bridge cranes and larger, and use brackets for bridge cranes smaller than 20 tons.

DaveAtkins

 

[chicopee]

With (2)cranes rated at 30 ton, ea and with more possible cranes< I would seriously consider columns. I worked in a heavy structural steel plant with over a dozen overhead cranes rated from 50 ton down to 30 ton and we had steel columns.

 

[hokie66]

The attached is a very useful design guide. It is freely downloadable from the CISC site.

http://www.cisc-icca.ca/files/publications/techpubs/design/craneguide/CraneGuide2E5P.pdf

 

[Forensic74]

IMHO, if the OP has to ask this question he should not be taking the liability "to do preliminary engineering work". Yea, you have CISC and DG7 but I've found a lot of this crane column design is based on a lot of experience, especially when you start wracking your brain about tolerances and fatigue. The design time can get way out of hand if you've never done it before.

 

[pioneer09]

I seen this requirement in CISC attachement.

3. Brackets should not be used to support crane beams with unfactored reaction greater than about 250kN.

Has anyone else seen this stated elsewhere. I would like to see it in a more specific tone.

 

[SteelPE]

Yes, it's the same requirement is DG 7.... but I believe that they get their information from CISC and reference it specifically. This is the same reference I made in my previous thread.

After the design of my last facility (a 15-ton crane with a 58 foot bridge), I would place my rule of thumb for bracketed crane columns at around 15-tons. Anything over 15-tons I would use a separate column system. This seems to fall in line with DaveAtkins. I have talked to others in the metal building industry and I have been told that they will frequently use stepped columns for large cranes. I have also visited a few fabricators, one of note had 2 5-ton cranes on the same line located on a separate column system braced back to the main building columns.