Wall Construction & Diaphragm

[hocho]

I'd like to know the following...

1. When you construct your reinforcement concrete wall, do you already plan the vertical dowels to the beam above it? how far into the beam do you put the dowels?

2. In our constructions. We put the hollow blocks starting at bottom (with dowels in ground beam) and add vertical dowels as we increase the height of the wall.

3. The dowel is connected to the beam above by later drilling 1 or 2 inch of hole and inserted it with a bit of epoxy.

4. I'd like to know if this technique would make the walls still follow the one half rule where the floor diaphragm above would carry half of the seismic mass of the wall.. or would the wall lateral seismic mass be fully concentrated in the same floor diaphragm (and not shared one half by the floor above.. how much would the above diaphragm share the lateral load then? I need to know an estimate because I'm computing for the contribution of walls to the seismic lateral load).

 

[JAE]

1 to 2 inches of epoxied dowel length isn't enough. The epoxy manufacturer should have some data on how much embedment is required. I would think it would be more like 4 to 8 inches.

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[KootK]

4. I'd like to know if this technique would make the walls still follow the one half rule where the floor diaphragm above would carry half of the seismic mass of the wall

Yes.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[hocho]

In india.. they use solid brick infills.. in asia.. they use hollow blocks.. how about in the US and other countries.. do you use pure reinforcement concrete block with the rebars already connected into the beam before pour?

Most contractors I know just use 1 to 2 inch (they are lazy to drill deeper).. and they don't use low viscosity epoxy (this is so expensive) so it doesn't insert with the dowel but only outside.

In the event of strong seismic movement. I guess half the walls won't really go with the above floor diaphgram because the walls may just fall down or detached from the beams.

 

[KootK]

I often use block walls with light gauge channel thingys at the top for lateral restraint. Or intermittent clip angles.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[hocho]

I often use block walls with light gauge channel thingys at the top for lateral restraint. Or intermittent clip angles.

In ACI references and ACI based structural engineering books. They only mentioned about concrete wall.. what country are you? Are block walls just use for economy.. are these allowed in all codes or only for certain country?

Do you know of lightweight wall that is as strong as concrete wall? This can lessen lateral load.

 

[KootK]

I'm in Canada. We use block walls often. We also use light gauge steel stud walls and aluminum curtain walls which are obviously not as sturdy. I've never heard of masonry walls being outright forbidden in any jurisdiction.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[hocho]

Kootk

I'm in Canada. We use block walls often. We also use light gauge steel stud walls and aluminum curtain walls which are obviously not as sturdy. I've never heard of masonry walls being outright forbidden in any jurisdiction.

What lightweight walls have you used that is also fired rated. What is your thought about the Hardiflex sandwiched with a bit of concrete. See:

http://www.jameshardie.com.au/products/external-cladding/hardieflex-sheet/

Do think Hardiflex are fire rated?

What other lightweight walls that are popular now?

Thanks so much.