cracks in CMU walls - technical publications

[a2mfk]

I am searching for any technical publication, magazine article, basically any published and reputable source of guidelines to the evaluation of cracks in existing reinforced CMU walls. I have looked long and hard and yet to find what I need (NCMA TEK notes, google, my forensic books, etc etc.)

I have strong opinions on the subject, but I basically need some backup as this is a legal issue and laypeople like it when you cite magazines and tech bulletins.

I need to be able to hammer down with a document that essentially says hairline cracks in reinforced CMU do not normally represent a reduction in the strength of the walls to resist lateral wind loads. Generally speaking of 2 story houses, but this case it is a one story house, so very lightly loaded except for wind.

Thanks in advance.

 

[ishvaaag]

I think you are in a difficult position trying to prove something contrary to what the logical mind (common sense) understands: that any cracked state is closer to ruin than the uncracked. In the process you even resource to the worse of what can be found in "scolasticism", bad logic in what everything is retorted to intent, including axiomatic and unproven statements, arguing of only "extraordinary" states where the cracked states would be closer to ruin than the uncracked states.

So in the least you need urgently to reword your intent to a less haughty proposal: that in spite of being cracked, walls may (but might not) comply with the STANDING requirement for lateral strength that the original structural system (or at least a viable variation of it from a structural and code viewpoint) requires from them for safety, strength and stability, then concentrating in proving that this is the case of the walls you are considering in the case.

That is, if you want to work with truth, and not tall words used for deception.

 

[ishvaaag]

Here an example of how to model damaged masonry in a way that the cracked walls are reduced to plane stress cases with smeared properties, showing good correlation with experiment. So the proof you may require can be got from some reasonable new and reduced "smeared" properties for your walls.

http://alexandria.tue.nl/extra2/200313573.pdf

I understand that it is less cozier standing trying to prove something than axiomatically stating that you have the truth. But in the evidence of the cracked state that is the factual position.