TENSION ANCHROGE OF BEEM REINFORCMENT IN COLUMNS(thin Section) 1

[6288]

How to deal with the tension reinforcement anchorage in columns(10" depth) with 90deg hook.
Ldh REQ from int. face of column is 16.43in for #6 bar where as we have on 8" depth available after deduction of clear cover 2".

 

[BAretired]

Perhaps a freehand sketch would help in understanding your question.

BA

 

[ishvaaag]

In any case, two usual solutions are used:

1. Diminish the diameter of component rebar, to make the splice or anchorage length smaller.

2. Leave preinstalled the appropriate rebar in the column in the 90 deg shape, then have the splice with the beam, so you can have any length of splice in both the column and the beam.

In some cases the extant depth of column is anyway inadequate because there's not enough concrete to take the forces imparted by the rebar. This can be revealed by a strut and tie scheme. This I remember has been treated in this forum, at least in the context of minimum depth of footings for cantilever walls.

 

[6288]

Dear ishvaaag :
Can you please further clarify option # 2 .it is more appealing , how to install 90deg pre-install re bar then splice with the beam

 

[ron9876]

Likely need more smaller diameter bars. If this doesn't work may need a larger column.

 

[6288]

Dear ishvaaag (Structural)
Do you mean by the provision of u bars provided then splice with Top/Bottom Bars?

 

[hokie66]

What reinforcement at this location is tension reinforcement? If the column is only 10" deep, it can't be taking much moment from the beam.

 

[6288]

Column Size is 10"x42", it will behave as shear wall, its my thinking whts ur suggession, further connection detail is already attached for reference.

 

[ishvaaag]

I attach the sketch of the detail I refer to. By including the 90 deg supplementary rebar one gets proper anchor to the column. Other thing is that the tensile force is anyway limited to some value, since high forces may become too much for small depth anchoring elements, in this case, the column.

 

[ron9876]

I don't see where it would make any difference if you use a U shaped bar or a bar that extends from the column into the beam. In the end you are looking at the developement length of a hook and if you can't develop the needed reinforcement something will have to change.