ACI 318- Embedment plate & Rebar in place of Studs

[siddhams]

We are designing embedment plate (ACI 318 ) using rebar welded to plate. My queries are as below

1) Shall we design as per ACI 318 Chapter 17 ( Earlier Appendix D)
2) If so is it must that the re-bars to be either hooked or bent
3) If Embedment length is calculated based Table 25.4.2.2

Regards
MSB

 

[Ron]

Make sure the rebar and plate are weld compatible and a proper welding procedure is used. Such would require prequalification testing in the US under ACI 318 and the American Welding Society (AWS)

 

[dik]

You can get weldable rebar, else, have to make sure the rebar is weldable.

Dik

 

[siddhams]

Thanks But my question is is it must to bent or hook the rebar even the tension is less

 

[Prestressed Guy]

For rebar (or deformed bar studs) you design for embedment and not per appendix D Whether that development is by straight bar Ld or bend or hooked bar Ldh depends on how long the bars can be. If I use an embed plate in the edge of a wall panel I always use straight bars. If the embed plate is into a column where I cannot get full straight bar development I use bent bars.

 

[KootK]

- Unless you are purposely passing your rebar tensions into other reinforcing within the member, I believe that Appendix D style anchorage checks that address concrete breakout are appropriate, whether your bars are developed or not. To my knowledge, you don't need to hook the bars but it certainly wouldn't hurt.

- One popular approach is to use the appendix D provisions intended for post installed rebar which is not hooked (by definition I suppose). In that case, an additional check would be ensuring that your bars are developed for the force that

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you intend to transfer. If you can't achieve the necessary development over your developed length then hooks or end anchors may well help with that.

- HILTI's developed some pretty great software for rebar anchorage of this sort. You might look into the software and the theory behind it: Link. Europe seems to be taking the lead on this at the moment.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.