HSS TENSION MEMBER-HANGER

[hayeska]

looking to discuss design of HSS used as hanger for underhung crane rail support. HSS welded to plate; bolted connection to lower rail upper frame.

Thanks

 

[dik]

Is it being picked up from a beam above? I'd likely use a simple plate welded to the end of the HSS and bolted to the beam above and below.

Dik

 

[hayeska]

The hanger would be supported from the steel frame above (bottom flange) and would be connected to the top flange of the beam (crane rail) below.

I was hoping to review the steps for the analysis and or find a reference for this detail/calculation.

Thanks

 

[Lutfi]

This is what I always used to support under running overhead cranes:

1. Use four (4) threaded rod hangers sized to carry runway reaction.

2. I used a knee brace (angle, of tube or pipe) to carry the longitudinal reactions due to impact and traction.

3. I use, as required, a brace (angles work real well) to brace the runway laterally.

They point I was taught about these types of connections, you want them to float! Making the connections rigid is not preferable. This is due to dynamics of moving cranes. Of course variations of these connections are acceptable as long as they are structurally sound, economical and what the fabricators are accustomed to seeing.

I also recommend that you call local crane fabricators and pick their brains on how they done it in the past. Additionally, most crane manufactures will give you hand as far as the details are concerned.

I hope this helps.


Regards,
Lutfi

 

[dik]

Lutfi: I prefer the use of an HSS because it gives slightly better rigidity laterally and some resistance for up and down vertical translation. Bracing design should be as reqd by code or the crane supplier.

Dik

 

[Lutfi]

The use of HSS is perfectly fine. I would keep in mind that if we bolt the cap and base plates (or weld them) to beam flanges, the beam flanges should be checked for any imposed loads from a rigid connection.

While most of the time engineers consider a four (4) bolted base plate as a pinned connection, I maintain that it has a percentage of fixity. This fixity should be analyzed.


Regards,
Lutfi

 

[hayeska]

The max. reaction is 56k. Braced in both directions at the hanger. I would like to discuss HSS to plate welding; requirements, calculations and opinions about the connection.

Thanks