Minimum Reinforcing of Pedastal 1

[RMPE]

This is a waste of time to me but I have to resolve this question forced upon me by a Contractor's interpretation of ACI 318.

This concerns 46 inch square "pedastals" for a six legged water tank structure.

My interpretation: Use ACI 318 -10.8.4 and 10.9.1 for compression members and you get a minimum reinforcing ratio of 0.005.

or use ACI 318 - 15.8.2.1 for pedastals and you get a minimum reinforcing ratio of 0.005.

END OF STORY.

Contractor says you look at 15.8.2.1 and get 0.005Ag, "then" you go to 10.8.4 and divide by two to get a minimum reinforcing ratio of 0.005Ag/2!

THEN I GET THE COMMENT that ties are NOT required for pedastals!

Is there any validity to Mr. Contractor's theory. Thanks.

 

[Taro]

You are correct. 15.8.2.1 specifies the minimum amount of reinforcing that must cross the interface between a pedestal or column and the footing. This is NOT the minimum longitudinal reinforcing ratio in the pedestal or column itself.

 

[JAE]

Mr. Contractor may push for no ties but if you ask him to sign a nifty letter saying he takes full responsibility should the pedestal crack or fail - let's see what he does.

 

[jheidt2543]

Who is the Engineer of Record, You or Mr. Contractor?

 

[lutein]

RMPE,
First of all, if your pedestal satisfy the aspect ratio in Chapter 15, then theoretically, you do not need any reinf. for 'plain concrete' structure. However, it is always a good practice to provide minimal reinf., i.e. 0.005Ag for structural integrity and premature shear cracking in plain concrete due to accidental bending or impact during construction

 

[RMPE]

Obviously, it wouldn't be prudent to build a 200,000 gallon water tank on unreinforced pedastals in my opinion!

On the other hand, I do not see where it says "pedastals" have to be reinforced at all, only 0.005Ag across the "interface between pedastal and footing".

ACI said use the 0.005Ag.

Thanks for the comments