single bolted connection pinned and fixed ??

[ARNAR]

I am designing steel framed structures to support ceilings. All the hangers are fixed with ceiling with expansion anchors. In staad model if we consider the connection as pinned it fails in deflection but all the utilization ratios are very small. how we can conclude whether it is pinned or fixed ??

 

[hokie66]

If the connection has one bolt, it is pinned. Why do you need a computer model to analyze something like that?

 

[dhengr]

Nirmal Ar:
We can’t see it from here, so we have no real idea what you are trying to do. We could draw a thousand sketches meeting your description, each of them needing a slightly different attention, detail or analysis. So why don’t you draw a sketch with some dimensions, member sizes, loads, etc. to show us what you have in mind?

 

[slickdeals]

As Hardy Cross would say, “Strength is essential, but otherwise unimportant.”

 

[ARNAR]

@ hokie66: For find out reliable forces and deflection STAAD Pro V8i Used.

@ Dhengr : Please find the attached model. Hangers channel size C-12x19 0.9THK mm Stabilizer size C- 14x38 1mm THK Bracing L-25x250.9mm. I took 1.0 DL + 1.0 EQ load and that one is the critical load

@ Slickdeals : The Framing should satisfy the serviceability criteria.

 

[ENGINEER92]

What are your connections? You can consider them fixed. You just have to design the connections to transfer the moments. In my experience it is typically cheaper to merely up size the members over making all of those moment connections.

 

[rb1957]

how much moment can a single bolt react ? ... not much

another day in paradise, or is paradise one day closer ?

 

[atrizzy]

How much deflection are you permitting for a seismic load case for a ceiling? I would imagine the utilization ratios are quite small, and indeed the channels may deflect laterally quite a bit if simply supported, but is this a problem?

 

[MotorCity]

We cannot see the connections so its not possible to comment on whether its fixed or pinned. Pinned connections allow rotation. If you are seeing rotation of your members at their base (which it sounds like you are by your deflection observation) it is probably acting as a pinned support. Also, since you have diagonal bracing, it should be designed as pinned. If you have fixed supports, the bracing is not doing much (or the fixity at the base is not doing much)