Fixing of Crane Runway Girder to Concrete Corbel
Fixing of Crane Runway Girder to Concrete Corbel
(OP)
Good Day All,
I am designing multiple concrete structures which will house large lifting cranes, up to 20tonne lifting capacity.
I have searched far and wide but cannot find an example of a typical connection between the steel beam and the concrete corbel. I intend to bolt the bottom flange of the beam to the corbel (cast in bolts). Is it necessary to fix the top flange of the crane runway girder to the concrete column? If this is needed it may be problematic as we cannot cast bolts to the side of the column, so will have to post fix which is problematic as when drilling we could hit the rebar.
Has anyone done such a detail, how did you approach it.
Thanks!
I am designing multiple concrete structures which will house large lifting cranes, up to 20tonne lifting capacity.
I have searched far and wide but cannot find an example of a typical connection between the steel beam and the concrete corbel. I intend to bolt the bottom flange of the beam to the corbel (cast in bolts). Is it necessary to fix the top flange of the crane runway girder to the concrete column? If this is needed it may be problematic as we cannot cast bolts to the side of the column, so will have to post fix which is problematic as when drilling we could hit the rebar.
Has anyone done such a detail, how did you approach it.
Thanks!






RE: Fixing of Crane Runway Girder to Concrete Corbel
For your case with a concrete column and a corbel under the beam, I think the detail would be very similar at the beam area.
Yes, the beam top flanges need to be tied back to the column to take out the lateral forces from the crane. But the tie-backs must also allow rotation of the crane way beam ends.
See AISC's Industrial Building Design Guide 7: AISC Design Guide 7 link
RE: Fixing of Crane Runway Girder to Concrete Corbel
Watch where you bolt the bottom flange of the runway girder to the corbel. Usually the corbel is rather wide compared to a typical steel column. If this is the case and say 12" of the girder bears on the corbel and you bolt the girder say 2" from the end, you'll get prying on the anchors as the girder end rotates. I have seen very loose bolts like this on cranes as small as 5 ton with short spans. You'll need to minimize the effects of the girder end rotation on the anchors. One way is to install a steel bearing pad on the corbel such that the bearing area of the bottom flange of the girder on the corbel is minimized.
You will obviously need to have girder tie-backs on the top flange. If you cannot drill the column, try to come up with something that will encompass the column (wrap around it) to attach the tie backs to. Seems drastic, but from my experience, post installed anchors don't fair well under cyclic loading.
RE: Fixing of Crane Runway Girder to Concrete Corbel
I would suggest a channel seat or rail clips on castin anchors cast for your connection, these things need to be very straight and cast in anchors bolted to the flange are never located properly.
How could you do anything so vicious? It was easy my dear, don't forget I spent two years as a building contractor. - Priscilla Presley & Ricardo Montalban
RE: Fixing of Crane Runway Girder to Concrete Corbel
RE: Fixing of Crane Runway Girder to Concrete Corbel
The top flange brace is essential, but as others have said, it needs to be flexible parallel to the beam. Instead of casting in bolts, I would cast in ferrules. Post installed anchors are not the way to go.
RE: Fixing of Crane Runway Girder to Concrete Corbel
I have one further question. Or should I say two. The crane rail girder is 6 x 5.2m spans. Now would you rather have continuous beams or 6 x simply supported beams? I would think that the longest beam that can be safely transported to this site is about 16m. If it is continuous and I use channels as suggested in some of the replies to fix the beam to the corbel, the bottom flange may move laterally nder compression, causing buckling. Is it not therefore better to have simply supported sections?
Secondly, seeing that the rail is a total of 31.2m long, thermal expansion and contraction could be an issue. How would you deal with this issue. Also with regards to the rail that fixes to the top flange of the girder and which I assume must be continuous?
RE: Fixing of Crane Runway Girder to Concrete Corbel
And as indicated above, fatique is a major issue when designing crane beams and their connections, and cannot be overlooked.