How to do crack control according to ACI code

[LTTien]

Hi all,

This is new engineer design with ACI code.
I am doing a pond design and want to do the crack control.

I see that ACI 350.1 10.6.4.2 has some equations for crack control.
Also I see there's one exception that while the cover is greater than 2 in. mentioned in R10.6.5.
But there's no further how-to-to in ACI 350.1 nor in ACI 318-02.

Currently I am using a cover that is greater than 2 in. so I would like to know which equations I can use for crack control.

Thanks a lot!

 

[delagina]

you may want to look at pca design guide for tank that would have a step by step how to design tank with water.
as far as i know, crack control is just a formula that will have more reinforcement and tighter spacing.

 

[LTTien]

I would have explained more correctly.

There's formulas to calculate the reinforcement and spacing, but only for structure where the cover is less than 2 in.
Since I am using cover greater than 2 in., I try to find corresponding formulas but I couldn't.

 

[delagina]

Not sure why you said the formula is only for 2" cover or less.
first off, I don't see any R10.6.5 (not used).
I see this on R10.6.4

"The numerical limitations of z = 115 and 95 kips per in. for
normal environmental exposure and severe environmental
exposure respectively correspond to limiting crack widths
of 0.010 and 0.009 in. These z values were established for
cover equal to or less than 2 in. and should be based on this
value even when cover exceeds 2 in. Additional cover may
be regarded as added protection."

it looks more to me the limitation is for 2" cover or less.
don't see anywhere the 10-5 formula is only for 2" cover or less.

 

[LTTien]

Hi, please see attachment if possible.
There's explanation of the exception in R10.6.5
Thanks.

 

[delagina]

the pdf didn't have R10.6.5

my copy is aci350-01

 

[LTTien]

Sorry..... Resend.

http://files.engineering.com/getfil...-974d-b3fd4dd8a782&file=ACI_350-06_10.6.5.pdf

 

[delagina]

My interpretation, R10.6.5 is for "appearance" criteria only which is something you should not consider.
If you have 2001 version there is no R10.6.5 at all.

 

[canwesteng]

Neglect any additional cover beyond 2 inches when calculating the crack control parameter Z. Otherwise the spacing requirements become too onerous.