Lintel Design loading query

[jr2981]

Hi all,

Im currently trying to determine the loading on a Type C concrete lintel installed at the ground floor level in the gable outer block leaf wall, this is a timber kit frame for the inner leaf, the lintel is 3.15m total length with a 2.85m clear span, the issue i have is that there is a doorway opening on the first floor which runs all the way down to this new lintel, so there is a 0.9m portion of the new lintel at the right hand end of the 2.85m span which has no blocks above it, see sketch. Im struggling to determine what effect this first floor opening will have on the longer ground floor lintel and the guidance in BS5977-1 doesnt help me.

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Would anyone be able to give some advise on how to tackle this?

 

[phamENG]

I'll admit, I don't understand the English language, at least in construction terms, but I can try to help. By inner and outer leaf, do you mean this is a veneer wall supporting only self weight while the timber frame carries all the structural loads? If so, it makes it easier. The opening on the elevated level breaks up any arching action you may have taken advantage of, so I'd take the reaction of from the upper lintel and spread it through the wall at a 2:1 slope down the wall to get a distributed load at the lower lintel. Then superimpose the load from the wall above the lower lintel.

 

[SlideRuleEra]

I agree with phamEng's approach the to problem by ignoring arching action. In addition to the loads he addresses, also superimpose loading from:

1) Live load applied to top of the "Type C" lintel.

2) Any dead load applied to the wall directly above the elevation of the "Type K9" lintel.

3) Above the elevation of the "Type K9" lintel, any live load applied to the wall and/or the "Type K9" lintel.

The USA Brick Industry Association has a Technical Note about "Structural Steel Lintels". I realize you have concrete lintels, but pages 3 and 4 of the 7 page document concern how to apply loads to lintels in masonry walls... and that is true for lintels of any material (structural steel, concrete, wood, etc.).

Any dead load on the "Type K9" lintel may be subject to arching action, as described in the Technical Note.

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