Page 140 - Buried Pipe Design
P. 140
114 Chapter Three
B
’
’
HD
Figure 3.23 Coefficient B′ as a function of H/D, where H is height of cover over
top of pipe and D is diameter.
Buckling for typical pipe installations. For determination of external loads
in normal pipe installations, use the following equation:
W
w h w R w c P v q a
D
where h w height of water above conduit, in
w specific weight of water (0.0361 lb/in )
3
P v internal vacuum pressure, lb/in 2
atmospheric pressure less absolute pressure inside pipe,
lb/in 2
W c vertical soil load on pipe per unit length, lb/in
In some situations, it may be appropriate to consider live loads as
well. However, simultaneous application of live load and internal-
vacuum transients need not be considered. Therefore, if live loads are
also considered, the buckling requirement is satisfied by
W L
W c
w h w R w q a
D D
where W L live load on the conduit (lb/lin in of pipe).
Extreme caution should be used when considering large-diameter
pipes. The above equations assume the external pressure (or internal
