8. Design of Coastal Structures
245
8 3.4 Wall of rubble foundation
The pressure distribution for this case is shown in Fig. 8.10.
F" = (l-rz)F 1
M" = (l-rm)Mj
(8.13)
F” is force against the wall above the foundation. M'f is moment about
the bottom (point A on Fig. 8.10). Moment at point B is given by
Mb = (1 ~ rm)-^ ~ b(l ~ rï)-F'>
or
>
mb = ma~ bF"
(8-14)
The values of (1 — rTO) and (1 — r/) may be obtained from Fig. 8.9.
8.3.5 Breaking wave forces on vertical walls
Minikin Method (1955,1963) can give forces 15 to 18 times those calculated
for non-breaking waves. The maximum pressure assumed to act at the SWL
is given by,
bd b>
(8.15)