New and Existing Structure

[ENGJP22]

Hi guys, I have the following job, There's an existing structure and the client wants to add a new one to complete the second floor area and I have a question:
How would you join both structures into one?
I was thinking about anchoring dowels into the existing slab (with epoxy resin) and into de new slab so they would move together.

What do you Think? Do you have a better solution?

 

[dik]

Are you thinking of a composite concrete slab? You might be surprised at how many dowels you need to achieve composite action... the approach can work if you have adequate strength reinforcing. Can you provide additional steel framing, with or without added steel columns (steel beam in line with the new wall)?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[HTURKAK]

The statement (anchoring dowels into the existing slab) implies the bldg is RC with RC slab or Steel ..with composite slab..

What ever the structure is, if i were , i would prefer steel frame with light steel columns and beams and make sure that the existing slab and and the whole structure is suitable for new additional loads..

 

[phamENG]

As indicated by dik and HTURKAK, we need more details. Construction, materials, configuration, etc. Can you draw a section through the joint with your proposed method?

 

[ENGJP22]

Hi guys, we are talking about a masonry structure with a concrete slab. The new structure should be a masonry system as well

 

[dik]

Can you use the masonry wall as a deep beam? to support the slab with dowels?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[ENGJP22]

phamENG I was thinking on something like this, the dowel is only to unite both structure so they can move together during an earthquake, I'm a little worried that by doing this there will develope a negative moment in this point.

What do you think?

 

[dik]

Can you line the beam up with the wall? and, maybe eliminate the beam?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[ENGJP22]

I didnt quite understand what you said, can you draw it for me?

 

[phamENG]

I think it's a workable concept. As for the dowel, if you only want it to work for lateral (shear) loads and not tension that could come from bending, use a smooth dowel and wrap it in a bond break. If you do want to restrain tension but not a negative bending moment, slide it down below the resulting neutral axis of the slab. Then its effectiveness in bending drops off a lot.

 

[dik]

misread the problem... I was thinking that the wall was new and use it as a deep beam to support the slab. In lieu of a dowel, you may want to support the new slab on a steel beam.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[ENGJP22]

phamEng when you say a bond break you mean grease or something like that, in the end that its going
to be in the new slab?

 

[phamENG]

Correct. I've even seen old drawings that call for newspaper to wrapped around the smooth bars to keep the concrete from bonding to it. (Not advocating for it, but I've seen it done.)