Question on AASHTO ASD Culvert Design 1

[Stewie_]

Hi, Dear All,

I got a quick question on AASHTO ASD culvert design. The plan has some standard note telling "AASHTO 1957 --- f.s = 20000 psi, f.c = 1200 psi, n =10, V = 90 psi, U = 300 psi".
I know f.s, f.c and n. My question is on V and U.
1. Is V concrete allowable shear stress?
2. What is U?

Thank you so much for the help.

Stewie

 

[bridgebuster]

90 psi for shear sounds right for 1957.

U might mean bond stress. When I get home Friday I'll check my old AASHO.

 

[Stewie_]

Hi, Dear Bridgebuster,

Cool, thank you so much. I thought the same, the bond stress.

Thanks,
Stewie

 

[bridgebuster]

Stewie,

There was no definition of U in the 57 AASHO; then again, there isn't any nomenclature in the book. Anyway, I would say it's bond stress. The photo is from the 57 AASHO.

 

[Stewie_]

Hi, Dear Bridgebuster,

Thank you so much for the help. You are the man!

Thanks,
Stewie

 

[bridgebuster]

You're welcome Stewie.