Minimum Pier Reinforcing 4

[STR04]

All,

Where in ACI 318 does it state that for compressive members that are oversized for architectural purposes or maybe for geotechnical reasons can we defer from the 0.01 Ag to some lesser value?

TIA

 

[ronstruc]

I remember checking this a while ago. If I remember correctly it was allowed in the old code (I think 94' UBC) to put the minimum amount of reinforcement in a compression member based on the required size of the member. However in the new code, IBC and ACI 318-02 that provision does not exist. I believe that the designer needs to use the actual area of the compression member, not what is required, to calculate minimum area of reinforcement.

 

[WillisV]

Actualy it is in the code: ACI-02 Section 10.8.4 allowd you to base minimum erinforcement on a reduced effective area not less than one-half of the total area. So essentially you can go down to 0.5%Ag for min. reinforcing if the strength ok when checking with the reduced section. Also see thread507-123265

 

[ronstruc]

Thats right, now I remember why I thought it didn't exist. It doesn't apply to me because of being in a region of high seismic risk.

 

[JAE]

Don't forget that ACI 318 does NOT directly apply to drilled piers (see 1.1.5). For drilled piers, ACI 336 applies yet it then cross references back to the following 318 sections:

7.10
10.2
10.3
10.8.4 (the one dealing with this post)
10.9
10.15