241
_______________________________________
OF ENGINEERING FORMULÆ.
_ Traction on Roads.
Resistance in lbs. per ton on Different Roads,
exclusive of Gravity.
Stone tramway _________ 20 lbs. per ton.
Paved roads .............. 33
Macadamized roads .. .. . ’ 44 to’67 ’’
Gravel __________________ 150 u,s ’’
Soft sandy and gravelly ground 210 ,,
Tractive Force of Horses.
Rate in miles per hour =2 3 31 4 41 5
Tractive force exerted) 1ri_ „„
by horse in lbs. ~ ^3 62 41
Paved Roads.
Foundation, 1 inch of sand on 12 inches of
gravel well punned, in 3 layers; or a layer of
hydraulic concrete, 8 inches thick. .
.Paving of granite, or trap blocks, 4 inches wide,
9 inches deep, 12 inches long.
Dimensions of Roads adopted in Central India
(‘Koorkee Treatise.’)
1st.
feet.
108
T8
30
30
20
18
1
1
25
Width of land in ordinary cases .. ..
Ditto when land is valuable__________
Width of roadway...................
Width between parapets of culverts ..
Ditto bridges above 10 feet waterway
Width of metalling, moorum foundation
Depth of ditto................... ,,
Ditto, broken stone ...............
Maximum gradient, 1 in ..........
Class of Road. '
2nd.
3rd. i 4th.
feet.
80
62
24
20
18
15
1
20
feet.: feet.
72 i 64
54 54
20 I —
18 ■ —
U -
14 —
20 1 18