elastic modulus for clay masonry

[rheewin]

from ACI530 section 1.8

Em= 700 f'm for clay masonry.

where can i get the value for f'm?

 

[Lion06]

Table I (page S-10) of the 2008 MSJC (ACI530-08).
It's dependent on the type of mortar and the net area compressive strength of the masonry unit alone.

 

[rheewin]

1000 psi for clay masonry?

i think it is too high.

is there another table for value?

 

[concretemasonry]

You just "think" it is too high?

If you do not not agree with the with the ACI 530 table values, where else do you get current accurately research values for the f'm?

I have served on the MSJC for many years and always thought the position was quite conservative. You will have to back some old research to find accurately justified differences that you can hang your hat and license on.

I am sure you can find a different value somewhere, but is it supported?

Dick

 

[Lion06]

Why do you think that's too high? What do you typically use?

 

[youngstructural]

And why do you typically use it? Code values have recently gone up due to research which showed the system to be stronger than previously thought.

Although a separate issue, this has happened to an even more dramatic extent with Concrete Masonry.

I am not talking US code values, but I would think the progress would be similar to CSA & AS/NZS codes.

Cheers,

YS

B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...

 

[Ron]

I have tested many clay bricks in compression. It is common for the strength of the brick alone to exceed 8000 psi (yes, that's 8000 not 800). Mortar is relatively low in strength, usually near 1000 psi (yes, type S is supposed to be 1800 psi, etc. but the reality is that compressive strength of mortar in the field is usually fairly low because the mixing procedures are so sloppy and masonry cement provides little margin for error in compressive strength)

So...the value in 530 is reasonable.

 

[steve1]

Perhaps the OP was refering to clay tiles and not clay bricks. I have an old handbook of clay tile engineering. It lists compression strengths (based on the kind of clay) ranging from 290 psi to 5640 psi