AASHTO 8.17.2.1.3 If the depth of ...

[edward1]

In reference to AASHTO 8.17.2.1.3 "If the depth of the side face of a member exceeds 3 feet, longitudinal skin reinforcement shall be uniformly distributed along both side faces of the member for a distance d/2 nearest the flexural tension reinforcement. The area of skin reinforcement (Ask) per foot of height on each side face shall be => 0.012(d-30). The maximum spacing of skin reinforcement shall not exceed the lesser of d/6 and 12 inches. Such reinforcement may be included in strength computations if a strain compatibility analysis is made to determine stresses in the individual bars or wires. The total area of longitudinal skin reinforcement in both faces need not exceed one-half of the required flexural tensile reinforcement." If I have a hammerhead pier, does this apply to the cantilever portion of the pier cap ?

 

[Philitup]

Hello,

I believe this requirement relates more to reinforced concrete grade beams than pier caps.

Regards,

Phil

 

[edward1]

I contacted Georgia DOT Bridge Engineering Department 3/28 and asked Mr. John Tiernan about this. He said this was a change in the amount of skin reinforcement required for deep beams from the previous AASHTO Edition and should be required for the cantilever part of this hammerhead pier.

 

[mike80]

Edward,

I would agree that it would apply to your cantilever. It appears this would apply to any deep beam, such as a pier cap on columns or hammerhead. Our state DOT, Ohio, interprets this the same way also.

Mike

 

[FM1]

edward1,

My answer to your post is "Yes".
At times we have to read the code sentence by sentence and conform to it. in your design case for instance;

Are you designing a flexural member? Yes
Is it deeper than 3 feet? Yes

Then the article in question applies.

in the case of pier caps where we are dealing with deep sections you will have to provide some facia steel. we never leave it unprotected, this article is a good starting point as to the amount of steel. I am not sure as which would always govern but check temp/shrinkage steel at 0.125 in²/foot also, it may translate to more steel.

good luck