Page 301 - Buried Pipe Design

272 Chapter Five

P o 190 lb/in 2

P o p
190 150
3
3

W W o P o 1900 190 1130 lb/ft
1130 1111
Thus, try is okay. For embedded-cylinder pipe, the transient capacity
is 1.4 times the design capacity.

1.4 W o 1.4 1900 2660 lb/ft
1.4 P o 1.4 190 266 lb/in 2

Case I (no surge):

266 150
3
Max. load 2660 2017 lb/ft
266
Safe live load 2017 1111 906 lb/ft

Case II (no live load):
1111 2
3
P 266 1 247 lb/in
2660
Safe surge pressure 247 150 97 lb/in 2

These excess capacities are for transient conditions only. The pipe
should not be expected to perform with a sustained soil load of 2017
2
lb/ft or with a sustained internal pressure of 247 lb/in .
Problem 5.1 For the above example (embedded cylinder), try the following
combinations of W o and P o . For the cases that satisfy design requirements,
find the safe live load and safe surge pressure.

W o P o
1800 200
2000 185
1800 190

Indirect Methods
Traditionally the Marston-Spangler indirect theories have been used
for designing concrete pipe. In 1983, the indirect design procedures
were included in a new section of the American Association of State
Highway and Transportation Officials (AASHTO) Standard