×
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

Weight of Precast Unit.

Weight of Precast Unit.

Weight of Precast Unit.

(OP)
Hi Engineers,
In calculating the weight of a precast unit is it the volume of concrete by the reinforced density of concrete only or is the volume of concrete by the the reinforced density of concrete plus the weight of rebar. I need clarification please.

RE: Weight of Precast Unit.

I've never seen concrete weights refined any more than the volume times 150 lb. per cubic foot. But I guess it could be made much more complicated for a small increase in accuracy.

RE: Weight of Precast Unit.

For a typical concrete mix and typical reinforcement, 150pcf is pretty representative. Most concrete mixes really come in around 140-145pcf without the reinforcement.

I've occasionally used 160pcf for heavily reinforced sections, and I've once accounted for the actual weight and ratio of reinforcement (when the CG of a bridge section with concrete deck and steel truss members was critical to the operation).

RE: Weight of Precast Unit.

Usually I use 150pcf like these other folks said. That said, to directly answer your question, most of the time you are good just using that ballpark figure. W_reinf_concrete_unit = Vconc * 150pcf
You could get the density of the mix and multiply it by the volume of concrete MINUS all the volume of reinforcement, stirrups, etc. Then add to that the volume of steel times about 490pcf to get a total, but you'll find that it it usually isn't worth your trouble.

RE: Weight of Precast Unit.

Agree with above. As an example, 1 cubic foot of concrete at 145 pcf + 1% min reinforcing yields a unit weight of about 150 pcf. Use 150 and the steel is included unless heavily reinforced as Lomarandil noted.

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