Interface Shear Between Wall and Slab. Does Reinforcement Need to be Fully Developed on Compression

[Quade999]

Hi Everyone,

If I have a situation like the one below where I have a retaining wall connected to a footing slab with the reinforcement having enough embedment for tension development only, does the reinforcement on the compression bending side of the wall need to be fully developed for the compression yield strength at the interface? Basically, the hook extending into the slab has enough embedment to attain yielding in tension but not in compression (as hooks don't contribute to compression development). For interface shear, the codes say that the reinforcement has to be fully developed on either side, but I take it that they mean fully developed for the yield strength in tension (as the reinforcement provides a clamping force. i.e. resists the shear with tension). If both bars shown have full development for the tension yield strength, then do they both contribute to interface shear resistance? Or do I need to meet compression development length requirements?

Thanks

 

[KootK]

Wait until Koot sees this thread. He will school all of us on "wrapping a moment around a corner."

Well, everyone except you. In fact, you might be getting a KootK Xmas card this year for stepping up and fighting the good fight on this.

Anyone who is agnostic as to the direction of the hooks on the vertical, tension bars of a retaining wall:

1) Does not understand the fundamentals of concrete joint design and/or;

2) Has not read the exhaustive thread that JoelTXCive linked to. And I wouldn't blame anyone for that as it's rather long.

A plate welded to the end of the bar would serve just as well (probably better).

I strongly disagree with this. As Joel intimated, the name of the game is transmission of wall moment around the corners such that it can be transmuted into footing moment. Neither development nor anchorage -- not even great anchorage -- accomplishes this with certainty. A welded plate may well not be sufficient to do the job and won't ever be better than lapped, and appropriately radiused, reinforcing rounding the corner. A welded plate is likely to fail a strut and tie examination of the joint.

I'd be happy to debate this in detail with any challengers but ONLY after they confirm that they've read 100% of the thread that Joel linked to. I bled myself dry fighting the good fight there and I'll not repeat the effort needlessly just to save others a little, light reading.

 

[BAretired]

I am not very familiar with the strut and tie model but the sketch below is the way I see the retaining wall problem using a plate as anchor at the bottom of the tension reinforcement. The horizontal reinforcement on each side of the wall can be extended as far as desired to develop anchorage.

@KootK, Where exactly do you see a problem?

BA

 

[BAretired]

Anyone who is agnostic as to the direction of the hooks on the vertical, tension bars of a retaining wall:

1) Does not understand the fundamentals of concrete joint design and/or;

2) Has not read the exhaustive thread that JoelTXCive linked to. And I wouldn't blame anyone for that as it's rather long.

1) Perhaps I don't, but always willing to learn something new. It should be possible to explain briefly. I'm a quick study.

2) I have not read all of it and do not intend to read all of it as I expect there are better sources of information on the subject.

BA