Moments induced in a masonry wall
Moments induced in a masonry wall
(OP)
Greetings masonry designers:
Any hints on how to calc permissible locally applied bending loads on an unreinforced masonry wall (assume no openings, and vertical height known).
Eg, I want to bolt an awning onto a brick wall subject to uplift. Bolts spread 'x' cm (in) apart. Wall subject to applied bending due to loaded cantilever awning, and tension on bolts.
so brick mortar shear (to prevent pull-out of brick from anchor) and localised wall bending needs to be checked.
Any hints on how to calc permissible locally applied bending loads on an unreinforced masonry wall (assume no openings, and vertical height known).
Eg, I want to bolt an awning onto a brick wall subject to uplift. Bolts spread 'x' cm (in) apart. Wall subject to applied bending due to loaded cantilever awning, and tension on bolts.
so brick mortar shear (to prevent pull-out of brick from anchor) and localised wall bending needs to be checked.






RE: Moments induced in a masonry wall
BA
RE: Moments induced in a masonry wall
Obviously something like a small domestic shelf bracket is ok - it's just stepping up in size till something says "NO MORE!!"
The way I see it, looking at all potential modes of failure, I'd need..
1) shear strength of mortar to prevent the brick with the anchor from being pulled out or pushed in from direct tension or comp.
2) resistance of the brick or effective group of bricks from rotating or tilting within the wall, resisted by compression from wall ht above
3) direct vertical lifting
I'd think it might be similar to a mass block of concrete pad resisting a cantilevered post where overturning resistance and compression at the toe is considered.
It's complex - I agree
why an I asking?
Someone has installed a bracketed awning that has been up for several years. I want to do one similar - but justify that it can work.
Cheers
RE: Moments induced in a masonry wall
RE: Moments induced in a masonry wall
What if it's solid 2 or 3 skins, still unreinforced, but solid masonry. Hence weight of wall above.
Surely there must be something!
RE: Moments induced in a masonry wall
Millions of basement walls would disagree :>
RE: Moments induced in a masonry wall
RE: Moments induced in a masonry wall
Again, this is not the best thing to do. I would recommend tieing your strucutre back into the studs/wall and check those for the additional load. Brick is a veneer, and a poor veneer in most cases, not structural in the typical structure.
RE: Moments induced in a masonry wall
Apply the same mechanics as plain concrete.
.. just a thought.
RE: Moments induced in a masonry wall
Code is AS 3700 Masonry Code (Australia) 204 pages.
Structure is an OLD hotel, 2 stories, external walls are about 6m (20') high.
Walls are rendered, so I'd need to do some destructive testing to ascertain mortar condition and type.
I'm expecting to assume zero tensile strength. I do however expect to find it is SOLID masonry, not brick veneer against timber frame like domestic BV.
Possibly 2 or 3 veneers, hopefully at least 2 veneers as a solid construction on the outside.
So my assumption, as above, is to assume stability based on net vector reaction of lateral and vertical load.
Like a mass pad footing where e <= D/6 so that the pad doesn't tip. No tension assumed.
Problem is also ensuring compressive capacity of the mortar isn't exceeded by this. (Like checking soil pressure at the toe of an eccentrically loaded or moment pad footing).
Get where I'm going with this?