Fully vs partially composite beam 3

[Iasonasx]

Is there a good reference for this subject? I don't remember how we determine the number and size of shear studs to get a fully composite beam.
Thanks!

 

[Agent666]

Your local code should cover this in detail.

But typically to be fully composite you need enough studs to either fully utilise the slab in compression or the full steel section in tension. This is essentially the maximum amount of force you can transfer across the steel/concrete interface.

Because this is usually a very large number of studs which cannot fit within the length of beam available and/or you don't usually need the full 100% composite capacity or stiffness from a capacity standpoint, most beam designs would typically be partially composite.

In a partially composite beam the maximum force you can transfer is basically the sum of the shear stud capacity within the shear span. This means a lower capacity and lower stiffness, so it depends on what you're after design wise.

https://engineervsheep.com

 

[driftLimiter]

AISC Design examples have good practice problems for these types of beams.

 

[DCBII]

I'd add that the beam needs to be sized to limit deflection before the concrete has gained strength and composite action is available. This can lead to a larger beam size that doesn't warrant going fully composite.

 

[Iasonasx]

Actually all I need is the method to determine the size (1/2, 5/8 or 3/4) and the spacing of shear studs. I know how to deal with all the rest. My goal is to determine the above so that I have fully integrated composite beam.
Thanks

 

[driftLimiter]

The method includes transform section, and shear flow at the top of the WF to determine the required spacing of a fastener with a given shear strength. AISC has a method that is fairly straightforward again you can refer to the examples there is a whole section on composite steel-concrete beams. [URL unfurl="true"]https://www.aisc.org/globalassets/aisc/manual/v15.1-companion/v15.1_vol-1_design-examples.pdf[/url]

 

[JLNJ]

AISC used to have more on composite beams right in the specification, but much of the practical info has been moved to the commentary.

Check out Section I3.2 in the fifteenth edition Commentary to the Specification. Page 16.1-381 (and following) in my book.