How to control concrete beam depth? 2

[dr. rifat]

Hi,
We have to design a rcc frame structure.I have a query about this .We have to design a building which LL=80psf,slab thickness 6".A Beam tributary area is about 340 sft,beam size 12"x20".How to reduce the depth of this beam?If we design it as a t-beam is it sufficient?




RIFAT

 

[hokie66]

You left out the most important factor, the beam depth. If strength is the issue, you can make the beam wider. If deflection is the problem, additional width may not solve it. Post-tensioning?

 

[dr. rifat]

If strength is the issue, you can make the beam wider. If deflection is the problem, additional width may not solve it.

How to meet those criteria?If we increase reinforcement,is it sufficient?

RIFAT

 

[concretemasonry]

Dr. Rifat--

I suggest you contact a structural engineer.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[JedClampett]

What's the span?

 

[ahypek]

I know this may not a direct answer to your question but have you considered removing the beams completely and going to a flat plate? What are your spans like?

 

[BAretired]

How to meet those criteria? If we increase reinforcement,is it sufficient?

Increasing reinforcement may be sufficient if strength is the only problem but it won't help deflection very much.

Your code should specify minimum recommended beam depth for various conditions of continuity; it is usually uneconomical and inadvisable to reduce beam depth beyond code recommendations. A simple span beam should have a minimum depth of Ln/16 for normal density concrete and Grade 400 reinforcement. This value should be suitably modified for one or both ends continuous or for different grades of reinforcement or lightweight concrete.

BA