Page 42 - Pipelines and Risers

16 Chapter I

MODE 1 MODE 2

MODE 4

LATERAL BUCKLING OF PIPELINE PAST ROCWUMP REGION

ELJldud

BUCKLE
WAVELENGTH

- MODE1 BUCKLE
_-__--_.
MODE2 BUCKLE
......... .. ... . MODE3 BUCKLE
---- MODE4 BUCKLE

Figure 1.6 Lateral buckling of pipeline.

Another method is to accommodate the buckling problem by permitting the line to deflect
(snake) on the seabed. This method is obviously cheaper than rock dumping, and results in the
line experiencing lower loads. However, the analysis will probably have to be based on the
limit-state design, as the pipe will have plastically deformed. This method is becoming more