Strength of Reinforcement and Deflection in the Beam

No, because Young's Modulus is very nearly the same for all steel.

thats mean if we use the reinforcement steel (Fy=2800kg/cm3) dont not cause any deflection in beam

• I don't understand your question.
• Load causes deflection, not Fy.
• Your units for Fy are incorrect.

wisam,

Just to be clear, for two beams reinforced with identical reinforcement having two different yield strengths, the deflections should be identical for identical loads.

If the beam with the lower strength steel requires more reinforcement to carry the load, then the area of steel increases, so moment of inertia increases, hence deflection decreases.

So you could say that deflection is indirectly related to Fy.

ba/ael

I mean with my question if I have two beam,

1-if two beam carry the same load but each one have reinforcements with different yield strengths.

2- if two beam carry different load but each one have reinforcement with same yield strengths.

which case have more deflection?

1. Deflection is equal if bars are same size.
2. Deflection is proportional to load.
   

ba, good answers, but I wouldn't waste my time on this one as he/she needs to go back and study the basics and principals of reinforced concrete design and analysis again....and again.....and again...... :-(

For the OP: Obtain a copy of "Reinforced Concrete Design" authored by Professors Leonard Spiegel, PE/PhD and George Limbrunner, PE. Study in hard and thoroughly if you want to be a successful Civil Engineer!!!

If you are lucky you'll be able to download a free Ebook of the textbook, or you may find a cheap used copy (older Edition) in Ebay or Amazon.com. I learned reinforced concrete design from this book when it was only in a rough manuscript format (mimeographed pages....not even photocopied. I still have it in my professional reference library after all of these years!!!! LOL) way back in my community college days over 33 years ago, then graduated to Wang & Solomon's wonderful textbook (much more involved). In fact, the late Prof. Spiegel was head of the Civil Engineering Technology Dept. at Hudson Valley Comm. College. Prof. Limbrunner was one of the CET staff there and is a former US Navy SeaBee. I learned a lot from both men and am forever grateful I was one of their students!