STEP
DEFINITION
UNIT
D
Depth of the manhole
m
Manhole Diameter =
Width of bottom concrete slab =
Width of top concrete slab =
Thickness of slab =
1.2 m.
1.5 m.
100 mm.
Dà
Iwâ
1
1.5
2
2.5
25%
4.97
4.88
4.81
4.77
50%
3.1
2.9
2.77
2.69
75%
2.25
2.06
1.95
1.87
100%
1.65
1.52
1.44
1.39
