Normal Weight Concrete vs. Light Weight Concrete Composite Constructio
Normal Weight Concrete vs. Light Weight Concrete Composite Constructio
(OP)
We are designing slabs on metal deck for a 2nd floor office building. It will be composite construction - i.e. steel beams with shear studs on top.
Does it matter if normal weight concrete is used vs. light weight as long as the required concrete strength is achieved?
Other then the dead weightt and added costs I am trying to understand the pros & cons between using the different weights for the composite construction design.
Any help would be appreciated.
Does it matter if normal weight concrete is used vs. light weight as long as the required concrete strength is achieved?
Other then the dead weightt and added costs I am trying to understand the pros & cons between using the different weights for the composite construction design.
Any help would be appreciated.





RE: Normal Weight Concrete vs. Light Weight Concrete Composite Constructio
For instance, a 2 hour fire rating would require 4.5" NW or 3.25" LW over metal deck. Another possibility might be 2.5" NW over metal deck plus spray on fireproofing. Which one is more cost effective would determine the way I would go.
You should be familiar with the costs in your area to make the proper selection.
If you have no required fire rating, I would choose normal weight because of the large cost premium to use lightweight. As an aside, finishers do not usually like lightweight.
RE: Normal Weight Concrete vs. Light Weight Concrete Composite Constructio
RE: Normal Weight Concrete vs. Light Weight Concrete Composite Constructio
Couple other things to keep in mind:
- you need more composite studs for lightweight concrete than normal weight. See AISC Chapter I (Green Book).
- all other things being equal, normal weight concrete is often cheaper than lightweight.
- if you know who the contractor will be, talk to them first. Many (most) contractor/subs will preferr to place normal weight concrete as placing and finishing normalweight is less man power intensive. Contractors often bring in extra finishers if the pour is lightweight concrete in comparision if the pour was done in normalweight.
RE: Normal Weight Concrete vs. Light Weight Concrete Composite Constructio
RE: Normal Weight Concrete vs. Light Weight Concrete Composite Constructio