3.1 Load model
3.1.1 Forces
The forces Pfr,a and Pfr,b, in kN,
to be considered for the strength checks at sections a) and b) of
side frames (specified in figure
2; in the case of separate lower brackets, section b) is at
the top of the lower bracket), are given by:
 
where:
|
Ps
|
= |
still
water pressure force, in kN |
| = |
 when the upper end of the side frame span h (see figure 1) is below the load water
line
|
| = |
 when the upper end of the side frame span h (see figure 1) is at or above the
load water line
|
|
P1
|
= |
wave
pressure force, in kN, in head seas |
| = |
|
|
P2
|
= |
wave
pressure force, in kN, in beam seas |
| = |
|
|
h, hB
|
= |
side
frame span and lower bracket length, in m, defined in figures 1 and
2, respectively |
|
h' |
= |
distance, in
m, between the lower end of side frame span h (see figure 1) and the load waterline
|
|
s |
= |
frame spacing,
in m |
|
PS,U,PS,L
|
= |
still water pressure, in kN/m2, at the upper and
lower end of the side frame span h (see figure 1), respectively
|
|
p1,U, p1,L
|
= |
wave pressure, in kN/m2, as defined in 3.1.2.1, below
for the upper and lower end of the side frame span h, respectively
|
|
p2,U, p2,L
|
= |
wave pressure, in kN/m2, as defined in 3.1.2.2, below
for the upper and lower end of the side frame span h, respectively
|
3.1.2 Wave pressure
3.1.2.1 Wave pressure p1
.1 The wave pressure p1, in kN/m2,
at and below the waterline is given by:
.2 The wave pressure p1, in kN/m2,
above the water line is given by:
3.1.2.2 Wave pressure p2
.1 The wave pressure p2, in kN/m2,
at and below the waterline is given by:
.2 The wave pressure p2, in kN/m2,
above the water line is given by:
where:
|
p1wl
|
= |
p1 wave sea pressure at the waterline
|
|
p2wl
|
= |
p2 wave sea pressure at the waterline
|
|
L |
= |
the distance,
in m, on the summer load waterline from the fore side of stem to the
after side of the rudder post, or the centre of the rudder stock if
there is no rudder post. L shall not be less than 96%, and need not
be greater than 97%, of the extreme length on the summer load waterline. |
|
B |
= |
greatest moulded
breadth, in m |
|
CB
|
= |
moulded
block coefficient at draught d corresponding to summer load waterline,
based on length L and moulded breadth B, but not to be taken less
than 0.6: |
| = |
|
|
T |
= |
maximum design
draught, in m |
|
C |
= |
coefficient |
| = |
|
for 90
≤ L ≤ 300 m
|
|
| = |
|
|
Cr
|
= |
|
|
k |
= |
1.2 for ships
without bilge keel |
| = |
1 for ships with bilge keel |
|
kr
|
= |
roll
radius of gyration. If the actual value of kr is not available
|
| = |
0.39 B for ships with even distribution of
mass in transverse section (e.g. alternate heavy cargo loading or
homogeneous light cargo loading) |
| = |
0.25 B for ships with uneven distribution
of mass in transverse section (e.g. homogenous heavy cargo distribution) |
|
GM |
= |
0.12 B if the
actual value of GM is not available |
|
z |
= |
vertical distance,
in m, from the baseline to the load point |
|
ks
|
= |
 at aft end of L
|
| = |
 between 0.2 L and 0.6 L from aft end of L
|
| = |
 at forward end of L
|
|
|
= |
Between the above specified points, ks shall be varied
linearly
|
|
kf
|
= |
0.8
C |
|
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