×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Slab on Metal Deck Construction Joint Spacing

Slab on Metal Deck Construction Joint Spacing

Slab on Metal Deck Construction Joint Spacing

(OP)
Does anyone have a reference for maximum pours for slab on metal deck?

I have seen drawings that seem to indicate 160ft or 10,000 sf.

An exhaustive google search doesnt turn up much.

We recently had a 350 ft building that was placed in one pour and seemed to exhibit cracking with "loud cracking sounds" according to a tenant. I'd like to make sure we are limiting our pours to a realistic amount based on something that can be backed up.

Thanks,
G

RE: Slab on Metal Deck Construction Joint Spacing

(OP)
perhaps, there is a reference that indicates construction joints are not required, too?

RE: Slab on Metal Deck Construction Joint Spacing

I've typically seen 400 c.y. of concrete in one day's placement as maximum.

TopKnot's last reference (the vulcraft link) only states that EXPANSION joints are needed between 200 to 250 ft. through the entire building....not construction or control joints in the slabs.

RE: Slab on Metal Deck Construction Joint Spacing

I have never stipulated construction joint limits for slab on metal deck nor am I aware of loud cracking sounds. I am interested in others experience with this.

RE: Slab on Metal Deck Construction Joint Spacing

We don't specify construction joint spacings in our slabs-on-metal-deck. Regarding spacing of expansion joints, we have gone further than 250 feet. The spacing of expansion joints depends on building geometry, location of the lateral load resisting system, pinned versus fixed column bases, heated or un-heated building, expected temperature differential, etc. Refer to this publication: Building Research Advisory Board of the National Academy of Sciences (NAS, 1974) published Federal Construction Council Technical Report No. 65: Expansion Joints in Buildings.

Regarding the "loud cracking sounds", could this have been "banging bolts"? How do you know it was slab cracking that was making the noise?

RE: Slab on Metal Deck Construction Joint Spacing

(OP)
First, I am NOT looking to specify contraction or control joints. I am interested in determining if there are recommended limits on concrete placement volume.

I have several drawing sets from some high end structural companies that put limits on their pours. I want to determine the basis for these limits.

We are aware of bolt banging and the reports do not seem to match the 'shotgun blast' we read about. I hesitate mentioning this here, as to how preposterous this sounds, but the tenant said he saw cracks opening up while hearing the sound! In any case, the sounds have subsided and there have been no reports since.

I am not convinced that our long pour led to this, I just want to do my research to make sure we have our bases covered.

RE: Slab on Metal Deck Construction Joint Spacing

I agree with you. I doubt that a large volume pour contributed to the cracks. The very nature of composite metal deck is going to tend to limit crack width due to shrinkage. The flutes and dimples in the deck will tend to prevent large sections of slab from sliding, thereby resulting in lots of very small cracks, versus fewer large cracks. We don't place limits on our slab pours - and we've never had any problems due to excessive shrinkage cracks.

RE: Slab on Metal Deck Construction Joint Spacing

I am currently working on a 10x60' suspended slab front porch. The deck spans the 10' direction and is temporarily shored. I can see how the decking provides crack control in the 10' direction. However, the deck has no resistance to forces perpendicular to the ribs (the 60' direction). As such, I am specifiying caulked control joints every 15' with the wire mesh stopping 3" short of each joint.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources