Sunday, October 16, 2011

RE: cantilver conc balcony

If you make a gap between the two slabs, it will not give you the behavior as we can except from a one continuous slab .I think it should not be done also because in the absence of concrete at the max bending moment point  your reinforcement may become a hinge and can collapse!



Salman Siddiqui


From: []
Sent: Friday, October 14, 2011 6:05 PM
Subject: cantilver conc balcony


I have an exterior concrete balcony with a 15' cantilever and 10' backspan.  I expect that no matter how thick I make slab I will get deflection and a crack over the support.  would it be best to detail a pour joint over the support or cut a crack control joint to control the crack?  joint could be filled with caulk / flexible joint sealer.


Also, project is located on a bluff about 1/2 mile away and 300' above the ocean (Malibu).  For slab exposed as finish, is anything recommend fro rebar protection?  I was thinking 4000 psi conc with w/c = 0.5 max, and 2" cover.  should I include something like xypex in the mix, or increase rebar cover, or am I distant enough from ocean that salt will be a minor issue?


Thanks in advance,


Paul Franceschi