no structural support to the renewal pipe, except for transmitting
loads.
2. Omitted.
B. Design Performance Limits and Design Parameters
1. The renewal pipe shall be designed such that the pipe shall not fail,
collapse, buckle, crack, or delaminate under loads. The maximum
long-term (50 years) calculated deflection under all loads shall not
exceed five percent (5%). The maximum bending strain (50 years)
developed in the wall shall not exceed three percent (3%) for
HDPE pipe.
C. The following parameters shall be used:
Depth of Cover Above Pipe Crown Actual
Depth of Groundwater Above Pipe Crown Ground Surface
Specific Weight of Soil 120 |bs./ft.
Wheel Load’ 16,000 Ibs.
Railroad Load” Not Applicable
Design Temperature 80°F
Shape Factor 4
Ovality Correction Factor
As applicable to pipe material for short-term
and long-term deflection
Deflection Lag Factor
1.0 (initial) 1.2 (50 years)
Modulus of Soil Reaction
1,200 psi
Short-Term Modulus of Elasticity
Seven (7) days under constant stress when
submerged in water, to be used for
unconstrained hydrostatic collapse resistance
design for highest external pressure resulting
from grout or groundwater above pipe.
Long-Term Modulus of Elasticity
50 years under constant stress when
submerged in water, to be used for
unconstrained buckling resistance design for
combined external loads from groundwater
and earth cover.
Minimum Factor of Safety
2.0, unless otherwise specified (not applicable
for maximum bending strain)
02769-8
