Should bottom reinforcement in slab continuous or not?

[tmgczb]

I submitted a question here early this week and some experts replied to me.
I still want to know，for two-way slab with beams in control building（anti-explosion building, maybe nothing special），Does bottom reinforcement in two-way slab have to be continuous?

 

[tmgczb]

In ACI 318-14, I find some details for slab-column systems. But for two-way slab with beams(continuous, not simply supported), I didn't find any details except the provisions given in 8.7.4. .
It says, in most cases but spandrel beams, bottom reinforcement in slab shall be allowed to anchored in slab. Does it mean bottom reinforcement doesn't need to be extended into supports?

 

[dik]

You can use this as a bit of a guide...

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

-Dik

 

[dik]

and this... if the slab is really regular, I generally run rebar continuous, alternating as shown; I use this for one way slabs, too.

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

-Dik

 

[tmgczb]

Thank you very much. From this example, I know part of bottom reinforcement shall be continuous at mid supports, could it be discontinuous at mid supports?

 

[dik]

The code stipulates the lap length at supports.

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

-Dik

 

[tmgczb]

What do you think of this article?

https://www.structuremag.org/wp-content/uploads/2019/05/0619-ci-6.jpg

 

[BAretired]

What do you think of this article?

https://www.structuremag.org/wp-content/uploads/20...

Did you post an article? I saw only a section.

Your initial question asks about two-way slabs. There is a fairly recent requirement in the Canadian code (and I assume the American code) requiring a certain percentage of bottom steel to pass through the column. For me, recent is within the last 10 to 20 years.

For one way slabs, bottom steel does not have to be continuous, but it doesn't hurt if it is. As I recall, the code requires 6" minimum embedment into the support.

BA

 

[dik]

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

-Dik

 

[dik]

It's a good idea... and the slab doesn't know where the rebar is, but this type of detailing may have saved the Florida condo.

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

-Dik

 

[tmgczb]

Thank you for your reply.But when it comes to column strip or middle strip, I usually consider it is applicable to slab-column frame system. Now my question is about two-way slab with beams. This is the website for the article from which I found the picture.

https://www.structuremag.org/?p=14580

 

[BAretired]

For two-way slabs with beams, so far as I know, there is no code requirement to extend bottom steel through the columns. It may be a good idea, but bars tend to become congested at the column, so it may be difficult to accomplish. That system is not common in my neck of the woods as the form-work tends to make it uneconomical.

BA