Replies

1. 
   Tim_Kline | Oct 07, 2001 10:10pm | #1

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   b WBA At Your Service

   Does the owner want you to do anything with the 10' openings with 1/4" plate ? Are you sure that the 1/4" plate isn't really an I beam or a T shape beam that is buried and hidden by the block ? A 1/4" plate spanning 10' should be sagging by now. If your engineer will sign on his work, won't your owner accept his/her numbers ? Isn't he ready to fire his own engineer by now after 2 weeks ? There are enough variables in your equation here that prevent any sane person from giving you an off the cuff response here such as "your choice of lintels is acceptable." Experiences such as discovering at the completion party that the owner was planning on a rooftop lounge for 300 guests make me shake in my boots.

1. 
   Andy_Engel_ | Oct 08, 2001 07:41pm | #2

   *I'm pretty sure that concrete block placed over an opening effectively acts as an arch. Therefore, any lintel is only supporting the weight of the blocks contained within the equilateral triangle directly above the opening. Any architects or engineers out there who can confirm this?Andy

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   Dylan_Seymour | Oct 08, 2001 11:32pm | #3

   *Engineers are paid to design and take responsibility for their design by applying their stamp and signature, not to make recommendations. Whatever you do, do not continue with construction without having someone else take responsibility for the design. This means in writing with stamp and signature. Liability is a very big word.

1. 
   George_Roberts | Oct 13, 2001 12:57am | #4

   *Andy ---Engineering is a lot of fun.If you leave out the equilateral triangle, you do have an arch problem.If you put in the equilateral triangle, the problem changes to a uniformly distributed load on the lintel.

1. 
   Tim_Kline | Oct 13, 2001 12:58am | #5

   *Andy, What about the weight of the roof system and the 50 psf snow load ? What if you can't fit the equilateral triangle above the lintel; i.e. 6 courses of block above a 14' wide door opening ?

2. 
   Dave_Richeson | Oct 14, 2001 09:47pm | #6

   *Why not use a bond beam with two continous pieces of #5 rebar grouted in the beam with 3500 psi concrete? I believe that any 18' high concrete block wall would be required to have one anyway. A bond beam and your lintel should get the engineer to sign and stamp his approval.

3. 
   Andy_Engel_ | Oct 15, 2001 02:21pm | #7

   *Those are good questions whose answer I would leave to an engineer. However, I've seen plenty of masonry fireplaces with 30 ft. of 8-in. block stacked over a 5 ft. long, 4-in. steel angle. If the arch-effect didn't come into play, I doubt that angle could handle the load.Andy

4. 
   kkearney | Oct 16, 2001 01:04am | #8

   *Andy,I think what you are seeing is what Dave is talking about. The angle is a support for U course blocks that are filled with rebar and concrete. That's the way I learned over 20 years ago from an old mason. KK

2. 
   Rich_Keith | Oct 16, 2001 01:04am | #9

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   I've got a nice job installing a 14'x14' door opening in a 12" block wall in a wharehouse w/18' ceiling. MY engingeer says the 4"x6"x5/16" angle iron I planned to install as the lintel was fine. The owner wants an I-beam 8 or 12 or 16" tall. (???). I employed an engineer that knows the owner to design what works, and after he beat me up on the phone for "using my gut" on the angles(they sag under their own weight), he has been 2 weeks and no answer. Funny, the existig 10x10 doors use 1/4" flat plate!. need to start soon. Can I hear from some masons/builders. Engineers can speak up too, but you guys are starting to get on my nerves. Thanks, Rick