24 
BULLETIN 1408, U. S. DEPARTMENT OF AGRICULTURE 
Corrugated-metal pipe is easily installed and on farm crossings 
it may be used without end walls. Very good small culverts can be 
made of concrete or vitrified clay pipe. They require good founda- 
tions. For corrugated-metal pipe, the coefficient of roughness, n 
in the Kutter formula, ranges from 0.019 for the 12-inch size to 
0.023 for the 30-inch size. For the same sizes of vitrified clay pipe, 
n ranges from 0.010 to 0.013. For large sizes the reinforced box 
will be more nearly permanent (pi. 2, H) or where good natural 
foundations exist arch culverts of plain concrete may be used (pi. 
2,D). 
Concrete end walls should be used on most types of culverts except 
wood. (See pi. 2, D, and pi. 2, J.) Figure 15 gives designs for two 
-W=4D- 
Hz D-* 1 
Front Elevation 
Concrete A3- 6 
Jih4 
l*B*j SECTION R-R 
CONCRETE END WALL 
(Straight 
r 
Front Elevation 
Concrete / : 3 : 6 
SECTION N-N 
End Elevation 
n 
CONCRETE END WALL N 
(With Wings' 
PLAN 
*-3-4liD4r4-* 
DIMENSIONS AND ESTIMATED QUANTITIES FOR ONE END WALL 
STRAIGHT 
WITH WINGS 
D 
B 
F 
Cu.Yds. 
W 
H 
F 
K 
L 
T 
Cu. Yds. 
in. 
ft. in. 
ft. in. 
ft. in. 
ft. in. 
ft. in 
ft. in. 
ft. in. 
in. 
12 
1 2 
1 
0.54 
15 
1 2 
1 2 
0.76 
18 
1 3 
1 3 
1.04 
2 II 
2 3 
2 
1 9 
8 
8 
0.55 
24 
1 4 
1 4 
1.62 
3 2 
2 10 
2 
2 4 
10 
8 
0.90 
30 
1 6 
1 6 
2.49 
3 II 
3 6 
2 
3 
1 
8 
1.25 
36 
1 8 
1 8 
3.60 
4 9 
4 2 
2 6 
3 6 
1 2 
10 
2.42 
42 
1 10 
2 
520 
5 3 
4 10 
2 6 
4 1 
1 4 
10 
3.08 
48 
2 1 
2 
6.85 
5 9 
5 6 
2 6 
4 8 
1 6 
10 
3.80 
Fig. 15. — Concrete end walls for culverts 
types, with dimensions and estimated quantities for various sizes of 
pipe culverts. These may also be used for box culverts. The U type 
is not recommended, since it requires approximately the same quan- 
tity of concrete as the type having wings set at an angle and is less 
efficient in reducing entrance loss than either of the two types shown. 
To reduce entrance losses, rounding the entrance to the pipe is 
more important than the type of structure used, as it will increase 
the capacity of a pipe culvert from 10 to 13 per cent. For this rea- 
son the bell end of clay or concrete pipe should be placed upstream. 
In soft soils the bottom of the canal should be paved with riprap for 
a short distance below the structure outlet. 
Drainage crossings under large canals also require culverts. The 
material should be more permanent than wood. Where pipe made 
