## Reinforcement ratio of concrete beams (T sections)

## Reinforcement ratio of concrete beams (T sections)

(OP)

Hello everyone, while reviewing my concrete notes a question rose in my mind.

In a rectangular section, why is the reinforcement ratio As/(bd), why use the effective depth (distance from top to the longitudinal reinforcement). Why not use bh where h would be the height of the member which will be a bit longer than d.

In addition i noticed that for T sections it still uses As/bwd where bw is the width of the web of the t section, why do we completely ignore the area of the concrete provided by the flanges why do we not include this in the reinforcement ratio calculation.

Thank you very much and wish you all the best.

In a rectangular section, why is the reinforcement ratio As/(bd), why use the effective depth (distance from top to the longitudinal reinforcement). Why not use bh where h would be the height of the member which will be a bit longer than d.

In addition i noticed that for T sections it still uses As/bwd where bw is the width of the web of the t section, why do we completely ignore the area of the concrete provided by the flanges why do we not include this in the reinforcement ratio calculation.

Thank you very much and wish you all the best.

## RE: Reinforcement ratio of concrete beams (T sections)

## RE: Reinforcement ratio of concrete beams (T sections)

## RE: Reinforcement ratio of concrete beams (T sections)

_{e}. The lever arm between the compression block and the reinforcement is, for most cases that the compression block falls within the slab, a = Asfy/0.85fc'b, and M_{e}_{n}= Asfy(d-a/2). Please see the code, or your textbook, for b_{e}, and the the case that the compression block consists of the slab and partial beam web (NA falls below slab).## RE: Reinforcement ratio of concrete beams (T sections)

## RE: Reinforcement ratio of concrete beams (T sections)