Residential Steel Beam on Masonry Block Wall Connection Detail?

[Redacted]

Hi there,

I am looking to create a new opening in a residential dwelling and was looking at potentially using a steel beam as the opening lintel instead of a concrete beam, as it seems it would be faster to install and the steel beam itself is not too costly.

However, I am not too sure about how to detail the connection between the steel and concrete wall. I was thinking of creating a pocket for the steel beam to bear on, on both sides, resting the steel beam in place, shimming the steel beam up to become engaged with the block work above and concreting the pocket. For an architectural standpoint, I was going to put drywall or something up to make the wall look like it was fully concrete.

I have sized two beams to work for the application : a W6x20 and a W8x31. However, the wall that the beam would hold up is 10" thick and if I use the 6x20, there would be a 2" overhang on either side, is this acceptable?

Bending strength of the beam didn't govern the calculations, the deflection did. With the 6x20 I am getting a8mm center deflection (with factored loads), and with the 8x31, I am getting 3.1x10-7mm. If I use the 6x20, one concern is this mid deflection, I assume I would need to bolt the beam mid span to the wall above. With such a low deflection for the W8x31, I don't think I would need to do this.

The W8x31 is about $400 more than the W6x20.

What are your thoughts on which size to go with? Also, any advice on the connection detail when dealing with small loads?

 

[dik]

I'd go with the W6... gives space for a bearing plate in the 8" course depth.


Dik

 

[XR250]

I agree with dik, that a 6" beam might be easier. Why not use a W6x25 if deflection is an issue for the 6x20?
How many courses of block are above the beam and what is the demand?

edit: nevermind - just saw you attachment thanks to phamENG

 

[phamENG]

I wouldn't worry too much about getting the beam and bearing plate in on coursing - the chances of the cells beneath the bearing points being grouted and reinforced is pretty slim, so you're probably looking at tearing up that first cell a bit anyway just to establish a solid bearing point in the wall.

The deflection in the W6x20 doesn't bother me - you said you calculated 8mm (0.314") with factored loads. L/600 for a 12' span is 0.24". Deflection calculations are typically done with service level loads, and since you're looking at 2' of block and a roof, I'd guess your factored loads are between 35% and 45% higher than your service level loads. Your factored deflection is 30% higher than allowable deflection with service loads. So you'll probably be okay.

 

[XR250]

For a 10" wall, you might consider two W6's side by side. Easier to handle and eliminates the overhang issue.

 

[r13]

I don't like the 2" overhang, if it is for my house, I would add cover plate to the W6, or use the W8.