Masonry shear wall - effect of openings on in-plane resistance

[neil254]

I am being asked to form an opening in an existing masonry shear wall. I am interested in the effect of this on the in-plane behaviour - with small window openings the wall can still be considered to be a single wall when calculating the racking resistance. However, as the openings get larger it would be more appropriate to consider the wall as two separate shorter lengths tied together by the remaining masonry above and below the window openings.

Does anyone have any rules of thumb/aware of any guidance on opening sizes in masonry shear walls? In particular at which point one needs to move from considering the wall as a solid wall with openings to two separate walls?

 

[JLNJ]

I don’t know of any rule of thumb.

You might be able to look at the largest section of solid wall and let it do all work.

The analysis with the perforations isn’t all that difficult for simple openings. Just be sure to take into account the control joints.

 

[masonrygeek]

There were a couple of articles in Structure magazine on the subject:

https://www.structuremag.org/?p=4474

and

https://www.structuremag.org/?p=3834.

I hope these help.

 

[JLNJ]

@masonrygeek

Those articles are for out-of-plane loading. I believe the OP was asking about in-plane “racking” forces.