Wall Reinforcement
Wall Reinforcement
(OP)
How should I design vert. reinforcement for the outer face of a foundation wall spanning vertically betweem two levels? Should I just put in some minimum reinf.? Inner face vert. reinf. will be designed for moment = wl^2/8. Is this resonable?
A similar question for slab having only one span, if bottom reinf. is designed for M=wl^2, should I just put in min. top reinf. at the ends of span?
A similar question for slab having only one span, if bottom reinf. is designed for M=wl^2, should I just put in min. top reinf. at the ends of span?






RE: Wall Reinforcement
RE: Wall Reinforcement
In general, I would provide 1/3 to 1/2 as much reinforcing at the supports of a simple span as I have designed at midspan. If I had to provide a rationale for this, I would point to the ACI coefficients in Section 8.3 which list a moment of wl^2/16 for a column support and wl^2/24 for a beam support. Of course, if minimum wall reinforcing requirements require a greater amount of steel, I would provide that.
RE: Wall Reinforcement
However, with earth pressure, you won't get a moment = wL^2/8 as the earth load is a triangular load, increasing with depth.
If the lateral load is wind or seismic, the forces will be in either direction, necessitating reinforcing on both faces.
I concur with HochwaltPE that for the beam, we usually provide the 1/2 to 1/3 reinforcing in the top at each end.