I agree with the methodology for openings within the brick. And I don't
disagree with what you or Harold has said. In my case I am not dealing with
a small opening but rather the complete length of brick wall to be
supported at each floor which is a lot of dead load. If I add the dead load
of the floor that is being supported then the beam size would take another
large jump. I usually don't include the DL of the floor structure as it is
already there before any brick is placed. I feel this is reasonable. In the
case of the BIA document it makes sense to add in the DL because it is
based upon a load bearing wall which is complete then loading with the dead
load of the floor. In my case the steel beam is supporting concrete floor
system which has the lintel attached to the edge of the floor slab.
Therefore the DL of the floor is already there caused the deflection.
I have always used the full DL of the brick/block supported by the floor
and the live load with L/720. Everybody thinks I am too conservative at
this. The OWSJ manufacturers will always want to use only the live load and
At 10:38 PM 1/24/00 -0500, you wrote:
>Remember that the lintel is only going to support a small triangular load
>providing the lintel is shored while the brick is being installed. I use a
>45 deg. triangle, but know that with brick it will probably be much less.
>Once the brick gets about a foot or so higher than half the span distance,
>will arch (providing you have an adequate thrust block), regardless of
>whether the lintel is shored or not.
>BIA is Brick Institute of America. I do the same thing that Harold Sprague
>does in designing lintels in following the BIA recommendations. The L/600
>and 0.3" limits are to prevent the triangular cracking that would occur.
>Hope this helps.
>A. Roger Turk, P.E.(Structural)
>David Handy wrote:
>>>Also: This is very strict, especially the 0.3" in one case this would be
>L/1100. Would it make sense to use shear studs on the perimeter beams to
>increase stiffness??? I would likely use a lesser amount for lateral
>support reasons anyway. I don't use shear studs too often; would the
>increase in stiffness be considerable or marginal?
>thanks again, David Handy
>At 06:36 PM 1/24/00 -0600, you wrote:
>>The UBC says to use L/600 for total deflection. The BIA says the lessor of
>>L/600 or 0.3". I tend to agree with the BIA unless you can cut the masonry
>>into smaller panels with properly detailed joints that can accommodate more
>>movement. I would recommend that you read the BIA Technical Note 28B.<<
David Handy, P.Eng.
The Thompson Rosemount Group, Cornwall, Ont. Canada
Opinions expressed are personal only.