Crane Runway Beam | Cantilever & Splicing
Crane Runway Beam | Cantilever & Splicing
(OP)
Looking at a crane runway beam and have a couple of questions:
System:
- 10 Ton overhead crane (for a small steel fab shop)
- Runway beam span = 68ft, but due to site constraints the end footing needs to be held back so the client wants a +/-60ft. span + +/-8ft. cantilever
I have never done/seen a cantilevered runway beam but I have a feeling it isn't a great idea. In general I know that continuous runway beams are discouraged, and therefore the cantilever is likely to suffer from the same fatigue related issues. Has anyone done/seen a small cantilever like this?
Based on the demand and span I could get a rolled shape to work but we can't get a single piece of that length to the site. I have read that welded splices should not be used in runway beams due to fatigue issues, what about bolted splices - are those also to be avoided?
System:
- 10 Ton overhead crane (for a small steel fab shop)
- Runway beam span = 68ft, but due to site constraints the end footing needs to be held back so the client wants a +/-60ft. span + +/-8ft. cantilever
I have never done/seen a cantilevered runway beam but I have a feeling it isn't a great idea. In general I know that continuous runway beams are discouraged, and therefore the cantilever is likely to suffer from the same fatigue related issues. Has anyone done/seen a small cantilever like this?
Based on the demand and span I could get a rolled shape to work but we can't get a single piece of that length to the site. I have read that welded splices should not be used in runway beams due to fatigue issues, what about bolted splices - are those also to be avoided?






RE: Crane Runway Beam | Cantilever & Splicing
Had to use a WT section welded to the top of the cantilever beam... stiffness an issue and also deflection.
Used Eurocodes to accommodate LTB for bottom loaded cantilever. Their LTB calculations accommodate the location of the load whether top, mid, or bot of the section.
Dik
RE: Crane Runway Beam | Cantilever & Splicing
I am not able to push the splice to the first interior support, that would require a 68ft. piece which we can't get into this site. I need a splice somewhere along the beam.
RE: Crane Runway Beam | Cantilever & Splicing
RE: Crane Runway Beam | Cantilever & Splicing
Also, see this thread for some good advice/thoughts:
Link
RE: Crane Runway Beam | Cantilever & Splicing
RE: Crane Runway Beam | Cantilever & Splicing
RE: Crane Runway Beam | Cantilever & Splicing
In the example from AISC design guide 7 they come up with a W27 + cap for a 70ft. span - for a 70ft. rolled shaped I'm assuming that it would be spliced, so I am assuming this is done. Everything I read suggests that you should not splice a runway beam, including the design guide itself. If I do a full pen and adhere to the fatigue requirements of AISC is there a problem?
RE: Crane Runway Beam | Cantilever & Splicing
Look at it this way, there are much longer spans used on crane runways which utilize plate girders. So for a 90 ft span plate girder, shorter lengths of plate have to be spliced together to create 90 ft long flanges and web. Although I would suspect that the plate splices occur at different locations.
RE: Crane Runway Beam | Cantilever & Splicing
RE: Crane Runway Beam | Cantilever & Splicing