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Re: Min. Steel in Concrete Column

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wow...this is really some column....isn't your governing factor in amount of
rebar just going to be reducing the size of the shrinkage cracks?

"Lutz, James" wrote:

> Per ACI 318-99, this reduction in steel percentage is no longer permitted in
> "regions of high seismic risk" (Seismic Zones 3 and 4).
>
> -----Original Message-----
> From: Sherman, William [mailto:ShermanWC(--nospam--at)cdm.com]
> Sent: Monday, February 05, 2001 3:00 PM
> To: 'seaint(--nospam--at)seaint.org'
> Subject: RE: Min. Steel in Concrete Column
>
> Refer to ACI 318-95 Section 10.8.4.
>
> -----Original Message-----
> From: Lao, Larry [mailto:LaoL(--nospam--at)vmcmail.com]
> Sent: Monday, February 05, 2001 3:59 PM
> To: 'seaint(--nospam--at)seaint.org'
> Cc: Kuhn, Bob; Wiegert, Tom; Lao, Larry
> Subject: Min. Steel in Concrete Column
>
>         We have a 4'x4' concrete column under 110 k axial load (D+L) and 60
> k-ft bending, both are at the bottom of the column, the column height is
> 18', about 4k of shear on top of the column. The 4'x4' was picked for
> supporting upper mechanical device.
>
>         Obviously, the min. steel requirement in UBC will put about
> 0.01*48*48=23 in^2 vertical bars into the column, which will provide about
> 2200k-f bending capacity or 4,000 kips of compression capacity. I remember
> have seen some requirement in the code, saying that if a design can provide
> 100% capacity over the demand, the 1% steel requirement can be ignored,.
> Basically, this is to prevent excessive rebars in a non-structural-sized
> column. Can anybody back me up on this?
>
>         Thanks
>
>