Page 115 - Trenchless Technology Piping Installation and Inspection

Existing Pipeline Renewal and Replacement Methods 81

Partially Deteriorated Pipe DR
Parameters: Groundwater 50 percent of soil cover

Maximum Existing Depth of
Required DR (d/t)
Pipe Ovality Pipe (Soil
Percentage Cover) (ft) E = 250,000 psi E = 400,000 psi
i i
2% 4'–10' DR69 DR80
11'–15' DR61 DR71
16'–20' DR56 DR66
21'–24' DR42 DR62
5% 4'–10' DR63 DR73
11'–15' DR56 DR65
16'–20' DR52 DR60
21'–24' DR49 DR57
10% 4'–10' DR54 DR63
11'–15' DR49 DR57
16'–20' DR45 DR52
21'–24' DR42 DR49

Gravity Pipe, Partially Deteriorated Condition

Designed by:
Checked by:
Date: 09/29/2009
Project name Design example—48 in. diameter
Location Anytown, U.S.
Client
Design Criteria

Pipe mean inside diameter (in.) 48.00 in.
Ovality (q) % 2%
Pipe minimum inside diameter (in.) 47.04 in.
External water (H , ft above invert) 12.00 ft
W
Depth of soil (H, ft above top of pipe) 16.00 ft
Soil modulus (E ) psi 1000 psi
s
Liner pipe flexural modulus (E) psi 250,000 psi
Liner pipe flexural strength (S) psi 4500 psi
Reduction to account for long-term effects (%) 50%
Factor of safety, N 2.00