Can anyone provide helpful criticism on this weird HSS moment connection detail? 2

[AaronMcD]

We are designing a display structure made up of HSS4x4x1/4 tubes that will require field assembly of all parts. It is a space frame, and deflection/vibration is the primary concern.

We are looking into bolted connections. The final dimension of beams and posts will be 6"x6" so we can't have bolts sticking out far.

This is the only thing I can think of, using slip critical bolts and a slotted connection. Among my concerns:

1) The slot at the end will cause some slight benting of individual HSS quarters due to eccentric shear. However, the slip critical connection - washer plates and internal plates likely provide enough stiffness and shear transfer.

2) Long individual plates will have angular deformation from the weld process. This is why I specify to leave in the erection bolt, which in turn is why I need slotted holes. I am worried that if try and compensate for angular deformation the plates may be too far off for proper connection in the field.

3) Are the welded nuts allowed, and will they provide enough torsion resistance during bolt tensioning?

4) I have already checked to be sure the first bolt will bring the plates into contact under a very small portion of it's total load. I will probably have to ensure that the bolt nearest the connection in tensioned first.

5) It's really weird and might scare whoever has to install it lol

 

[Tmoose]

"It will also support projectors so it can't be floppy."

Where will the projectors be mounted?
Are the projectors for business meeting presentations or never ending cycling montages of advertisers' goods, etc.

Is this installed on a ground floor? If not, I'm thinking that foot traffic within 50 feet may bring on complaints of shaky projectors.

 

[bones206]

I share CANPRO's concerns that your connection detail has a high chance of causing fit-up and assembly headaches.

This isn't necessarily going to help with your connection detail, but the constructive criticism I would offer is to forget the connection and re-evaluate the whole concept of your structure. In general, if you are using standard structural members in a manner that's driving you to design a really non-standard connection, maybe that's a sign to step back and look at other concepts. You and your design team have probably already looked at other concepts, but from my vantage point it seems like you are forcing the issue at a detailing level, when their might be a more elegant solution on a macro level.

Based on all the design constraints you've mentioned, the concept that I would explore would be something akin to temporary staging structures used at concerts and other events. i.e, lightweight welded space-trusses that can be bolted up with simple shear connections. It would be easier to assemble and stiffer as well. There are also standard fittings for mounting lights and projectors on round tube members. Of course you may have already ruled this concept out for other reasons.