Angle lintel above window

[kaspor]

Hello

I have to install some large steel angle lintels above some 5-6m wide commercial style windows. They are going to be installed in a brick veneer wall.

Due to width the lintels have to be welded to PFC beams (which are located in the timber wall cavity supported by SHS posts either side). The lintels will then sit above the window supporting brick work.

I’m not sure if you need to allow any clearance between angle lintel and the window itself. I see the engineering calcs are stating that the steal beams to which the lintels are welded to have up to 16mm deflection.

Typically the steel beams are 20mm above window height. But I don’t want to leave too much gap between the window and lintel as I’m not sure how to seal the gap later on.

Should a 20mm be allowed to deal with the beam deflection?

 

[JedClampett]

First of all, the title of your thread is the first 50 characters, so if you want a better response, you'll need to compose a title.
Second, I'm not sure I totally understand your question (I don't speak abbreviations), but if you want the brick lintel guidance I always use, go to the Brick Industry Association. They have a lintel one, but also many, many more.

 

[dik]

Do you have a cross section that shows the detail? I try to restrict lintel deflections to L/720.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[BAretired]

Deflection should not exceed L/600, which, for a 6m span, is 10mm. A single angle lintel is likely not practical for such long spans.

 

[kaspor]

Apologies, I rectified the thread title.

Cross section is attached in the link below

https://drive.google.com/file/d/1tNjgbqf6JvCWvycKxb-ltcGlahzQKO9_/view?usp=sharing

Calculation is also attached in the link below:

https://drive.google.com/file/d/1W7l_tVvO1DdRuwFaJ6KP-wLcuZJ6lXt3/view?usp=sharing

Calculation shows the PFC beam with deflection L/344.

The window is installed under the angle. Should a 20mm gap be allowed for under the beam to deal with this deflection? I don't want the window to buckle.

 

[BAretired]

L/344 is too much deflection. Maybe use HSS in lieu of channel. Deflection due to torsion needs to be included. Total deflection should not exceed 10mm.

 

[Greenalleycat]

A 5-6m wide window is a big sucker
Make sure your lintel system includes faceload consideration from wind or EQ
Getting sufficient out of plane stiffness may be challenging if its brick in a seismic area

 

[kaspor]

Thanks for the responses. I will re-visit the calculation, however my question is whatever the deflection is, 5mm, 10mm or 15mm, should there be a gap between the lintel and the window to account for this deflection? Otherwise the beam will put pressure on the window and potentially cause it to buckle?

 

[Enginerdad]

To answer your actual question, yes the window opening needs to accommodate the calculated deflection of the lintel plus some margin of error to prevent it from pressing on the window exactly like you describe. Typically that gap would be sealed and covered with brick molding.

 

[BAretired]

Put a note on the drawing indicating the amount of deflection expected. Dead load will presumably be in place when the windows are installed. If so, live load deflection is the only consideration affecting window installers.