Bending Flexural Vertical Bars in Stem of Retaining Walls after concrete has been placed

[CWEngineer]

When is it appropriate and not appropriate to bend reinforcement?

Currently, looking into some vertical (flexural) bars in the stem of a retaining wall that have already been placed in the concrete footing. The vertical (flexural) bars were placed 1 inch from where they were supposed to be, which was 3 inches from the earth face of the wall. Would it be appropriate/acceptable to bend these bars that were placed 4 inches from the earth face of the wall, 1 inch horizontally within say 4 inches in height?

Thanks

 

[hokie66]

It would not be acceptable. The effective depth to your bars would still be controlled by where they are located at the top of the footing.

As to when and how it is acceptable to bend bars, that varies with the situation.

 

[CWEngineer]

Yes, I agree that the effective depth to the vertical bars is still controlled by where they are located a the top of the footing.

But, was trying to get some guidance regarding the strength of the vertical bar if it is bend after it has already been placed in the concrete footing of the wall. By bending the bar, am I decreasing the strength? And if so, would this decrease in strength of the bar still acceptable?

Thanks

 

[TehMightyEngineer]

I'd consider bending (only once at any bend location) of bars already in place to be acceptable with no loss of capacity. Some concrete spalling at the concrete construction joint is to be expected.

Professional and Structural Engineer (ME, NH, MA)
American Concrete Industries

http://www.americanconcrete.com

 

[JAE]

Check out this ACI Q&A from Concrete International:

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[msquared48]

The question here is not so much the cover, as the decrease in the developed bending moment at the very base of the wall section. For an 8" wall where the steel was supposed to be at 3" from the vertical face (1.5" to 2" would be normal except for a footing bottom), the reduction in the developed bending moment simplistically would be 16/25 or about 2/3.

Perhaps that is good enough, but the engineer of record should confirm that is OK.



Mike McCann, PE, SE (WA)

 

[wannabeSE]

After reading the article JAE provided, I noticed ACI 318's commentary is not consistent with ACI 301-10's requirements for field bending and straightening in section 3.3.2.8. ACI 301 requires preheat for bars larger than #5.