Two Way Slabs With Drop Panels.
Two Way Slabs With Drop Panels.
(OP)
I am using the Direct Design Method to determine the design moments for a Flat Slab with End Span Simply Supported on wall. My main concern is the detailing of the reinforcement. I am following ACI, Fig. 13.3.8 – and it appears that some areas of my slab will be unreinforced on the top, see attached sketch. Should I include at least minimum area of steel?
Thank you
Thank you






RE: Two Way Slabs With Drop Panels.
1) Since this is the positive moment region for the slab, the reinforcment is not required by analysis.
2) That being said, this is the portion of the slab that is easily exposed. Because of that, I believe a small ammount of reinforcement is typically extended over this region to control cracking and such. However, this is usually at a significantely wider spacing thann would exist in the negative moment regions.
RE: Two Way Slabs With Drop Panels.
Usually we provide a 1/4 of the calculated top steel at column strip intersections in the column strip/middle strip intersection. These bars are then lapped over the column. So you get 1/4 + 1/4 = 1/2 and then we add the remaining bars as extra bars over the columns.
Hope that makes sense.
RE: Two Way Slabs With Drop Panels.
RE: Two Way Slabs With Drop Panels.
In addition to the advice above, don't forget that if you add top steel to just make yourself feel good, due to the thin sections in two-way construction, it's likely to make it harder to pour the concrete. So you haven't helped the structure, you've hurt it.
RE: Two Way Slabs With Drop Panels.
RE: Two Way Slabs With Drop Panels.
RE: Two Way Slabs With Drop Panels.