RSJ Spacers - Are they needed?

[John Stanley]

Guys,

Any advice..

SE specified bolts and spacers necessary. Builder has added bolts but not spacers. The work is up and he is saying spacers are not needed and is pushing back (basically refusing) on making changes now.

The beams sit right next to each other - no space in between - is it even necessary to have the spacers?

Hopefully someone can let me know what the purpose of the spacer is? is it purely to ensure the beams do not move apart?

I spoke to SE and he has advised if spacers not used and beams are not coming down I can weld a steal plate to the underside to tie the beams together.

Thanks in advance

John

 

[Bonni]

Theoretically, if the RSJ's are touching one another, you would think you wouldn't need spacers. The only time I've never used spacers when 2 L beams were bolted back to back. One SE told me on one job was that the bolting together and spacers is what gives the beams the additional strength. Probably why the SE wants the plate welded on below. Rule number one, we should just follow and implement what the SE wants because A. There's a reason, and B. So building Regs will sign it off.

 

[John Stanley]

Thanks Bonni,
The SE did also say that the beams were designed to work together. Maybe the spacers are a necessary if they give additional strength.

 

[Notch7]

I suggest posting this in the building regs section - there are professional,Structural engineers that frequent that forum.

I’m sure I read on here by one of the pros that spacers aren’t actually good practice as they allow twist…..I think that’s what I remember, I could be wrong.

I think it may depend on how the scheme works, what the load is and what else is connected.

 

[John Stanley]

Thanks Notch, will re-post now.

 

[Bonni]

I suggest posting this in the building regs section - there are professional,Structural engineers that frequent that forum.

I’m sure I read on here by one of the pros that spacers aren’t actually good practice as they allow twist…..I think that’s what I remember, I could be wrong.

I think it may depend on how the scheme works, what the load is and what else is connected.

Probably why in some instances, the bolt holes are specified in a pattern to prevent twisting.

 

[Bullet-Proof_Biscuit]

I would suppose the top and bottom (side) edges of beams are not totally straight, as made in the roll forming process, only the middle web would have a true dimension 'flatness', hence spacers ensure the beams would remain parallel when tightened together.

Notwithstanding above, builder did not follow agreed drawings, builder must follow agreed drawings...

I thought builders used bits of scaffold tube for spacers anyway..

 

[Dereekoo]

Deleted

 

[Bonni]

Later I found out that "i" beams suffer from torsion. When the load is applied, it might be slightly off centre which can cause the beam to twist. Depending on the application, they're specified to be bolted to one another with spacers. So correct in the first place, beams often get their strength by being bolted to each other with spacers