steel canopy - beam column connection 3

[mats12]

Im designing a steel canopy. All steel elements are hollow profiles (box profiles). All connetions are asummed as pinned. Because of that I braced a construction in roof plane

I have some thoughts about top of column - beam connection. I dont have much experiences with hollow/box profiles but in this case I have to use them.

Im wondering if connection shown in picture is alright in your opinion? Is there a better way?


Bolts are inside of a box profile so the beam would need to rotate quite a bit in order for considerable tension in bolts to develop. Is that right?

Bolts are definitely in tension when winds in blowing upward (resisting uplift) but forces are small.

Shear demands on bolts will be small too.

Is there anything Im missing? im not so confortable with shown connection (but it is aesthetically pleasing) so I want to make it sure before proceeding.

 

[Guest262653]

I'd just weld the two profiles together. Those bolts are very difficult to keep in position before tightening.

 

[mats12]

What if welding is not an option?

 

[robyengIT]

Google : "hollow sections in structural applications Wardenier"

You will find any type of connections (welded, bolted, etc)

 

[Guest262653]

You could also check the CIDECT design guides(

http://www.cidect.com/en/Publications/).

Plenty of information that can be be obtained for free.

 

[klaus.]

there are better way to connect......go ask the steel worker who is doing the work



best regards
Klaus

 

[XR250]

What if welding is not an option?

Why is it not an option?

 

[SAIL3]

I usually close off the ends of HSS members....that bm looks like it has torsion loads on it which would require closing off the ends of the bm if one is using the torsional capacity of that member...

 

[KootK]

If I understand the situation correctly, your canopy joists have vertical support at each end. Hence the nominal loads. As such, I'd be fine with your connection IF it can be physically installed as shown. I'm not sure that it can. And, like SAIL, I prefer to see cap plates on HSS for durability reasons.

As an alternative, you could extend your column cap plates 6" towards the middle of the frame and then fasten to the beam from below with blind bolts (check regional availability). Perhaps the design intent here is a "no bolt" concept. If so, it may be tough to get away from welding.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Leftwow]

How is construction going to bolt that in? I'd hate to be trying to tighten the nuts inside of a HSS section.

 

[atrizzy]

Are the nuts on the underside of the plate/inside of the vertical tube welded to the plate?

 

[klaus.]

Please DO NOT weld Nuts and Bolts !!!!


best regards
Klaus

 

[mats12]

klaus.

I dont know what do you mean.
DO NOT weld?

 

[klaus.]

do not weld nuts and bolts......

usually the material used for Nuts and bolts is not weldable





best regards
Klaus

 

[mats12]

I wasnt even thinking about welding bolts. Tnx for answer.

I was trying to avoid welding since it destroys galvanazing of an element where it is welded (at a joint).
So there needs to be another protection of steel (anti corrosion).

I decided to weld connection (butt weld).

Would you consider that a moment frame (horizontal loads are small), or it will be wise to add a stiffener between column-beam?

 

[klaus.]

would you rather wear a green or red shirt ?

There are many option to do such a structure.....depending on the 'boundary' conditions
- Architectural
- Production
- transportation
- erection
and on and so on .......




best regards
Klaus

 

[mats12]

Since I ll use welds, I was thinking to make a moment frame - so there is no need for bracing in a roof plane.

I like red shirts better

 

[dik]

Can you make your column width less than the beam width... it will help with welding. Can you eliminate the stiffener... costly to add.

Dik

 

[klaus.]

if you use cold bend tubes you are not allowed to weld at the corners
also depending on the wall thickness the corners are rounded ...so this butt weld does not work





best regards
Klaus

 

[Guest262653]

My suggestion:
- cut ends of column and beam at 45º and butt weld;
- keep your bracing at roof level;
- design connection as pinned.

For additional info, check CIDECT design guides 1, 3 and 9.