×
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

Composite slab

Composite slab

Composite slab

(OP)
Assume you are checking the design of an already erected steel floor (without pouring the concrete), and only one bay of the secondary beams failed , can i use a composite floor system and add studs only on the failed members ...?



ôIf you don't build your dream someone will hire you to help build theirs.ö

Tony A. Gaskins Jr.

RE: Composite slab

Sure. The only caveat being that, if there are no studs elsewhere on the project, it might be disproportionally expensive to add these studs. I was told that it takes about 1000 studs before it makes sense to mobilize and demobilize the stud welding equipment. Is the decking already on? Is the failure flexure or deflection?

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.

RE: Composite slab

(OP)
both!!, Flexural and serviceability.

a follow up question, we took a test material and sent to the lab and the elongation value is 40% is there any thing we could do to remedy this horrible situation.



ôIf you don't build your dream someone will hire you to help build theirs.ö

Tony A. Gaskins Jr.

RE: Composite slab

Might be worth checking with your contractor to see if they'd prefer studs or some localized flange reinforcement to rectify the situation.

I don't quite understand the elongation issue. Can you expand upon that?

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.

RE: Composite slab

(OP)
what i meant is we ordered a tensile test for the steel sections used in the project, and the result yielded a 40% elongation percentage.
i think the code permits an elongation value up to 23 .. !!



ôIf you don't build your dream someone will hire you to help build theirs.ö

Tony A. Gaskins Jr.

RE: Composite slab

Not sure what those elongation values mean other than it sounds like deflection will be a problem.

I agree with Koot that you should reinforce the steel section. I suggest this as opposed to studs because "composite" beam design is often controlled by wet-weight deflection (bare steel resisting freshly poured concrete weight). An undersized beam will probably deflect such that it will need plenty of extra concrete poured to make the slab surface flat. If you have headroom, add WT shapes by welding the end of the stem to the underside of the bottom flange of undersized beams. If no headroom, use a bottom flange cover plate and top flange angles as needed.

RE: Composite slab

Before you go spending a lot of money I have to ask: are you sure it's overloaded? And if so, by how much? If it's over capacity by, say, 30% then yeah, that should be addressed. But if, on the other had, it's over by, say, 3% ... well, thatt's not worth going to heroic measures to address.

I only ask because years ago I worked with someone who had his drawings checked and the reviewer told him he found a beam that was overstressed. The reviewer had performed his own calculations and concluded that a beam was over by .003%. My friend complimented him on finding it and suggested he show his findings to his boss, which, presumably he did. My friend never heard back from him.lol

Like calvin&hobbs, I'm not sure what the elongation test refers to unless it's a tensile test of a coupon taken from the beam.

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