Why Shear studs welded onto the Lysaght bondek ? 2

[devus]

hi there,
I'm freshie to engineering world and learning it.
Why Shear studs welded onto the Lysaght bondek and
would this have effect on a slab and beam?
thanks first.
Happy learning.

 

[Zambo]

Shear studs are welded to make the bondek formed slab and the steel beams a composite structure. Yes it will have an effect because the shear studs are part of the design.

 

[devus]

i c... but would it be just bondek + reinforcement + concrete? is there any significant reason why the shear stud is needed?

 

[Zambo]

You should call Lysaght to show you the design. They will also check the deflection of the bondek during casting of the slab, if the deflection is excessive props will be needed.

The studs make the bondek/concrete/rebar act as a composite structure with the beams. It is also possible to design without the studs in which case you have an RC slab supported by beams.

 

[apsix]

Zambo is correct; "Shear studs are welded to make the bondek formed slab and the steel beams a composite structure"
Forgive me if I'm simplifying too much, but it appears you are unsure of the definition of composite.
Basically with composite action the slab will be in compression and the steel beam in tension, the shear studs stop the tendency for sliding at the steel to concrete interface.
Without the shear studs the steel beam only would be carrying the load, and would therefore have to be larger.

 

[csd72]

Are the shear studs welded to the bondek or the steel beam?

 

[morokanu]

csd72,
shear studs are welded to beam, in order to achieve a composite beam section.
bondek + concrete is another composite section and there is no need for shear studs as bondek is shaped in such way that it locks in with the concrete and no sliding is permitted.

read again apsix's post, the concept of composite is very well explained.

 

[csd72]

Morokanu,

I know very well how this typically works, but the original post said that the studs are welded to the bondek.

There are some composie deck systems that have additional 'studs' in the bondek to increase longitudinal shear capacity, but I cant remember if bondek ever does this or if it is a uk thing.

 

[blihp]

Bondek is a australian 'wrinkly tin' / metal deck that can be used to provide composite action ie the same as holorib / ribdeck etc.

i suspect the query about it being welded to the bondek is because if one looks down on to the metal decking (bondek) from above, all you may see is the shear stud as the decking is covering the beam below. Consequently, if your not familiar with the system is may appear the the studs are welded to the bondek.

In reality, the shear stud is welded THROUGH the bondek to a steel beam below. This will allow the beam under to act compositely with the concrete slab. The effect of the studs on the slab design is minimal to negligble (they do have an important role in temporarily keeping the steel decking in the right place during construction).

"a wise man know his limits" anon.
blihp