Max reinforcement 1

[SemiPE]

Does the allowable maximum area of reinforcement apply to splice location of beams and columns? For example, if the code says max rebar area is 4%, and I use 3.9% as my design reinforcement and i would splice 1/2 of the total rebars on a certain location, that would result to a total rebar area of 5.85% at the splice location. Is this allowable?

 

[slickdeals]

The 4% maximum reinforcement limit provided comes from alleviating congestion and practically being able to place concrete. You can choose to stagger splice the reinforcement with 50% of the splice happening in one location (5.85%, in your case). You need to provide more specifics to your question to get a more specific answer, i.e., is this happening in a column that's part of a moment frame in a seismic area? If so, you cannot splice the bars at the locations of a flexural yielding (i.e. slab level). The splices should occur in the middle 50% of the column height.

One other thing you may want to consider is the use of mechanical splices (couplers), which will alleviate congestion. In addition, if you use ACI Type II couplers, then the splice can occur "anywhere", including locations of flexural yielding

 

[WillisV]

Code maximum reinforcement does apply at splice locations. 8% max in columns equals 4% max typical assuming all bars are spliced at same location to equal 8% max in splice zone.

 

[jayrod12]

WillisV has it correct. And even if you are only splicing 50% of your bars by the time you get to the end of your splice for the first 50% you need to start the splice for the next 50. Basically 8% is the max however that needs to include all bars at the worst case location for congestion which leads everyone to use 4%.

 

[SemiPE]

Hi guys, thanks for the replies. I see... so the max reinforcement does apply to splices, I have always been generous in sizing RC frames, so I was able to avoid these problem....until now that I am working with a person who has a preference for very slender elements. Any other cheaper alternative than mechanical couplers?

 

[WillisV]

More concrete is quite cheap.

 

[jayrod12]

^^ this

And it's fairly foolproof. They can't have their cake and eat it too, it's either cheap, or slender, rarely can it be both.