Simplified Design for Footings - Simplified Design of Reinforced Concrete Buildings - page 226

For the straight dowels, the minimum footing thickness h must be ˜ dc + 3 in.

In certain cases, the thickness of the footing must be increased in order to accommodate the dowels. If this is
not possible, a greater number of smaller dowels can be used.

#4 thru #11 column bars

#4 thru #11 dowels

d b d

h

d bf

d bf = diameter of flexural steel
d bd = diameter of dowel
r = Minimum radius of dowel bar bend

3" clear + 2d bf + d bd + r

3" clear

Figure 7-7 Footing Dowels

For the usual case of dowel bars which are smaller in diameter than the column bars, the minimum dowel
embedment length into the column must be the larger of the compression development length of the column
bar (Table 7-3) or the compression lap splice length of the dowel bar (ACI 12.16.2). The splice length is
0.0005 f y d b = 30 d b for Grade 60 reinforcement, where d b is the diameter of the dowel bar (ACI 12.16.1).
Table 7-4 gives the required splice length for the bar sizes listed. Note that the embedment length into the column
is 30 d b when the dowels are the same size as the column bars.