Concrete slender wall design 1

[Redeemd]

Does anyone have insight as to why ACI 14.8.2.4 exists? Why are we trying to reinforce a wall to prevent cracking?This seems to contradict the rest of 14.8, where deflections are a function of Icr. There is no commentary given on this.

 

[Bagman2524]

Leakage control perhaps.

 

[msquared48]

Also, most of the slenerwall designs were tilt-up, cast with the outside, architectural reveal face down, subjecting that face to high tension stresses from lifting. Hence the need for better crack control.

I have seen too many concrete tilt projects with crack problems from lifting over the years.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[hokie66]

ACI 14.8.2.4 just requires the bending capacity to be greater than the cracking moment, which is a typical requirement for all flexural sections. If the bending capacity when cracked is less than the cracking moment, failure would be brittle.

The reinforcement doesn't prevent cracking, but rather provides a reliable moment capacity after cracking occurs.

 

[BAretired]

I can't say it any better than hokie just did.

BA

 

[Redeemd]

Thanks all for your input. I see now that it is possible for Mcr to be greater than phiMn when you have a small d, such as one mat of rebar centered in a wall.