Deep beam reinforcement and flexure reinforcement 3

[NicoliA]

Does anyone know if the tension reinforcement used to resist bending in a reinforced concrete beam can also be used for the steel needed for tensile stresses caused from deep beam analysis? I would think so to some degree anyhow, but i do not have much experience on the topic.

 

[KootK]

It can. It's an either or thing. Either:

1) You design your beam for flexure the conventional way and supply reinforcing as required OR;
2) You design your beam for flexure using deep beam procedures and supply reinforcing as required.

It's one or the other but not normally both.


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.

 

[normm]

Thats right. The amount of reinforcement can be calculated by either method. But using deep beam theory the reinforcement should be spread
in the whole of tension zone near the surface of the web rather than accommodate it on one or two layers in bottom only.
There requirements were written in the British Code for dia and spacing of these reinforcements in the web to avoid surface cracking.
May be there are similar in ACI.

 

[rapt]

I would definitely have the tension tie reinforcement at the tension face in one or 2 layers. The whole strut tie theory for deep beam design requires this.

I would supply extra side face reinforcement over the depth of the member for crack control in the side faces.

 

[Retrograde]

The CIRIA guide on deep beam design states that the tension tie reinforcement can be distributed over a depth of 20% of the "active height".

The active height is defined as lesser of h or l where h is the beam depth and l is the span between the centers of the supports.

 

[TLHS]

I think Normm is talking about surface reinforcement for cracking, which you generally have to supply in members over a certain depth. Generally your main reinforcement would be as deep in the beam as possible and only spread out the surface reinforcement as necessary to meet those code requirements.

 

[NicoliA]

Thanks! you all have been really helpful.