Reinforced concrete beams

• pj33
In summary, the conversation discusses the process of converting steel beams into concrete and whether to transform them separately or as a single piece. It is recommended to find a book on reinforced concrete design for more information. The discussion also includes the importance of understanding balanced, underreinforced, and overreinforced beams. The rectangular concrete contains three steel beams for reinforcement and the total area is determined by the ratio of the steel's Young's Modulus to the concrete's Young's Modulus.

pj33

When I convert the steel beams to concrete, do I transform the several different beams into a single piece of concrete in order to do the calculations to find the second moment of area of the beam or do I transform each beam seperately into a concrete piece?
Intuitively, t seems reasonable to just convert all the beams into a single piece of concrete as the the cross-sectional area is usually small, but if it is true is it always valid?

I believe that we will need some kind of schematic, or more information at least.

pj33 and russ_watters

In a simple case like this.

My copy of Reinforced Concrete Design, by Spiegel and Limbrunner, has 18 pages on the design of rectangular beams with only tension steel. I recommend that you find a similar book because there is more to the analysis than what is implied in your question.

Hint: Read carefully the part about balanced vs underreinforced vs overreinforced beams.

pj33 and Lnewqban
pj33 said:
In a simple case like this.
What is the material within the rest of the rectangular cross section?
Does that concrete contain steel in any shape?

Lnewqban said:
What is the material within the rest of the rectangular cross section?
Does that concrete contain steel in any shape?
It is a rectangular shaped concrete which has 3 beams of steal in order to reinforce it. When I transforme the 3 beams, I have converted all 3 of them to a single piece of concrete with area mA.
A is the total area of the 3 beams of steal and m is the ratio of the steal's Young's Modulus to the concrete's Young's Modulus