AS3600 Mesh in Suspended Slabs
AS3600 Mesh in Suspended Slabs
(OP)
A builder just mentioned to us that he has heard people saying that mesh is not allowed as the primary reinforcement in suspended slabs in the new AS3600 code. I have only briefly looked through the code (mainly the new fire requirements), so can anyone help point out whether or not this is true?






RE: AS3600 Mesh in Suspended Slabs
http://www.sria.com.au/services/pubs/TN6.pdf
And the link is located on this page, which has a few others on the topic:
http://www.sria.com.au/services/pubs/main.html
I do not know about the latest edition (2009), but I would imagine that SRIA would have addressed such a change.
RE: AS3600 Mesh in Suspended Slabs
It's not just a matter of providing the equivalent area because there are many restrictions on the use of Class L in suspended slabs, and the strength reduction factors are lower, but it is not prohibited.
Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/
RE: AS3600 Mesh in Suspended Slabs
There is no direct substitution of low-ductility reinforcement for normal grade reinforcement.
RE: AS3600 Mesh in Suspended Slabs
1.1.2 Application
(c) Reinforcing steel of Ductility Class L in accordance with AS/NZS 4671—
(i) may be used as main or secondary reinforcement in the form of welded wire mesh, or as wire, bar and mesh in fitments; but
(ii) shall not be used in any situation where the reinforcement is required to undergo large plastic deformation under strength limit state conditions.
NOTE: The use of Ductility Class L reinforcement is further limited by other clauses within the Standard.
17.2.1.1
Ductility Class L reinforcement shall not be substituted for Ductility Class N reinforcement unless the structure is redesigned.
RE: AS3600 Mesh in Suspended Slabs
The other problem from a design/construction point of view is the depth to the design steel. When the mesh is layed on site, it is never done as your would require it to ptovide the most efficient lapping. You tend to end up with 4 sheets of mesh lapping in the worst way, resulting in a complete mess.
And you layers tend not to be what you asked for, so you need to assume the worst in both directions!