Concentrated Load on Masonry Wall - Lintel Design
Concentrated Load on Masonry Wall - Lintel Design
(OP)
In analyzing the effect of a concentrated load on the top of a masonary wall I have been confused by my resources. One resource says that a concentrated load can be neglected in analyzing a lintel if its distribution taken as 45° down a distance 4x the wall thickness stops before the apex of a 45°zone above the lintel because of the arching action. Other resources say the concentrated load should be distributed at 30° and down a distance of half the wall height. If this is the case most all concentrated loads on top of a wall above a lintel will need to be evaluated for there effects on the linetel? what happened to the arching action? I only have ACI 530-08 not ACI 530-05 but I believe there was a change to section 2.1.9.1?






RE: Concentrated Load on Masonry Wall - Lintel Design
BA
RE: Concentrated Load on Masonry Wall - Lintel Design
RE: Concentrated Load on Masonry Wall - Lintel Design
For the design of CMU, when considering arching I take the load down at 1:1 (45°).
RE: Concentrated Load on Masonry Wall - Lintel Design
If the masonry is not staggered (i.e. the vertical joints go all the way up) then I would definately not use arching action and would use a point load.
I would ignore arching in anything less than 4 bricks high.
RE: Concentrated Load on Masonry Wall - Lintel Design
I have been confused by this as well. According to "Six Minute Solutions for Structural I PE Exam Problems", the 45 degree method is chosen. It states:
"The concentrated load is distributed downward at an angle of 45 degrees over an effective length equal to four times the wall thickness plus the width of the bearing."
It then shows a diagram which is different that what you would expect....it shows the 45 degree triangle area drawn directly above the lintel, not below the load. It states that since the concentrated load is above the apex of the triangle that it does not load the lintel.
RE: Concentrated Load on Masonry Wall - Lintel Design
It is based on the historic testing of masonry and the load distribution without an effects of reinforcement, which can open the doors to other design concepts and load distributions.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Concentrated Load on Masonry Wall - Lintel Design
That's what I would expect to see, anything above that 45deg line will have the ability to arch over the opening as long as the opening is less than 8 times the thickness of the CMU.
RE: Concentrated Load on Masonry Wall - Lintel Design
RE: Concentrated Load on Masonry Wall - Lintel Design
But everyone had good advice, but I am confused. You guys don't show masonry control joints on your drawings??? I always have, I want control of this aspect. The architect then shows his stucco joints at the same locations and can add additional as necessary... This also may be critical in your lateral design, it has for me lots of times..
AVak (Structural)
" You never know when a vertical control joint might end up close to your concentrated load and do away with your arch-action."