One-Way Shear in Spread Footings
The one-way shear, or beam shear, is evaluated at a distance, d, from the column face or the reduced base plate edge. The value d is taken as the smaller of the reinforcement depth for the top and bottom flexure bars for the given direction.
The shear capacity is calculated using:
| Equation ACI-14 22.5.5.1 |
In this case,
d is calculated
from the footing clear cover and provided reinforcement diameter. The flexure
reinforcement parallel to the footing's larger dimension is taken to be the
closest to the footing bottom. If the footing is a square then the
reinforcement parallel to the major axis of the footing is considered to be the
closest to the footing bottom.
The ultimate shear, Vu, on the section is the total soil stress under the footing for the shear section under consideration. If any portion of the critical shear area is in tension, the program checks to see if the shear from the uplift portion of the footing using the footing slab self weight and surcharge controls the value of Vu.
In the case of spread footings, the
RAM Foundation module will not calculate shear
reinforcement. Thus, for the spread footing to be acceptable in beam shear, the
following must be satisfied:
| ACI 318-14 14.5.1.1(c) |
