One Way or Two Way shear stress 1

[edward1]

Attached are the post results of shear stresses SQX and SQY of reinforced concrete tank with 36.33' of fill.

 

[JedClampett]

I can see the problem.

 

[edward1]

Do I choose slab thickness so it is below 120 psi for one way shear or below 240 psi for two way shear?

 

[JedClampett]

I'd have to see the tank and your results (you didn't include them). I can never keep straight those STAAD stresses. But i believe the one way shear number is the one you need.
But I do reinforced concrete tanks all the time. If you gave the dimensions of the tank, the liquid level and wall thicknesses, I could tell you if they're right.

 

[edward1]

Jed, Tank is 7.67 feet long x 4.57 feet wide x 9 feet high with no appreciative water inside.

 

[edward1]

wall is 8 inch thick and slabs are 12 inch thick

 

[edward1]

http://files.engineering.com/getfil...258b-43ad-827d-cfa87e13e2e4&file=2360_001.pdf

 

[edward1]

P.S. This is 1/4 of tank due to symmetry

 

[JedClampett]

For a tank that size 8 inch walls might work, but I'd recommend 12 inch walls for constructability.

 

[edward1]

The attached pdf shows SQX and SQY shear stress that are not continuous across the slabs like they are for box culverts with this much fill? I think this is closer to punch through stress versus one way stress?

 

[JedClampett]

Edward, I started responding to you because I thought it was funny that you said to look at an attached pdf, yet there was nothing attached. I felt kind of bad for teasing you, so I engaged with you.
But seriously, you need to learn how to attach your pdfs.

 

[edward1]

Jed, You are correct. It took me several 6 posts and I finally got the attachment on post 7 above. But the point of discussion from the shear stress models was from these models were they one way or two way (punch through) shear stress? I finally got an answer from Sye at Bentley that these 2 models are one way shear stress. This lrfd load factor value is about 129 psi for 5000 psi concrete. Edward1