Crane Runway Moment Releases

[LeonhardEuler]

Working on the analysis of a structure supporting an overhead crane. Runway girder is bolted to bracket connections under the girder and a surge plate is bolted to the top of the girder.

Would it be safe to assume that this runway girder is a "pinned connection" and transfers only negligible moment to the stiffened seat connection and surge plate in all directions besides the "main bending axis" where the stiffened seat is in compression and the surge plate is in tension.

The crane running on this girder obviously has longitudinal, transverse, and vertical forces. I would only be considering moment from the vertical force with this assumption.

 

[LeonhardEuler]

Diagram attached

 

[hokie66]

Yes, crane runways like that are most commonly simple spans, thus pin supported.

 

[TehMightyEngineer]

Seconded hokie. In the past I've enveloped the design of the connection for some flexure in the girder, causing some torsion in supporting bracket while designing the beam for pin connections. Probably more conservative than required, though.

However, the stiffeners and bolts will transfer meaningful torsion in the crane girder into the supporting bracket but this is obviously their purpose and in the strong axis of the supporting bracket.

EDIT: Clarified some wording.

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

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