Added Bar Lengths in Two Way Slabs
Added Bar Lengths in Two Way Slabs
(OP)
I am a contractor looking for some help with regard to two way slab estimating. In particular verifying lengths of added steel for both column and middle strip areas. No one that I have been talking with has been able to give me a straight answer and when I compare an old shop drawing to calculated lengths based on the chart from ACI Code 13.4.8 I do not get the same number that the detailer used. Thanks in advance.
KrisM
KrisM






RE: Added Bar Lengths in Two Way Slabs
RE: Added Bar Lengths in Two Way Slabs
Top steel over the supports in both the middle and column strips should be a minimum length of 0.5 x span length (staggered 0.3 and 0.2L either side of the support).
The column strip will have additional bars that account for approximatley 25% of the total steel in the column strip. This accounts for the concentration of moment that occurs at the face of the support.
RE: Added Bar Lengths in Two Way Slabs
RE: Added Bar Lengths in Two Way Slabs
Kiss!
Old CA SE
RE: Added Bar Lengths in Two Way Slabs
Fully agree with you, at least it was my practice - to minimize complicate designs that causing high labor costs and fibraction/construction errors. I think the labor cost alone can fully compensate (in the US) the added reinforcement for most of the cases.
RE: Added Bar Lengths in Two Way Slabs
RE: Added Bar Lengths in Two Way Slabs
RE: Added Bar Lengths in Two Way Slabs
Neilly Davies Consulting Engineers http://www.neillydavies.com.au
RE: Added Bar Lengths in Two Way Slabs
RE: Added Bar Lengths in Two Way Slabs
During my time as a construction estimater, we took off the rebar shown on the structural drawings and added 10% to our take-off quantities to cover rebar lap and other contingencies. We checked quite regularly and worked it very well for us. It does make some difference on the larger sizes of rebar, so theoretically you could work out different percentages for each size of bar.