Environmental Engineering Reference
In-Depth Information
Table 2.16 Compressive strength of sea ice [24]
Return period [years]
Compressive strength of ice
s
0,k
[MPa];
Designations simplified after [26]
Southern North Sea,
Skagerrak, Kattegat
Western and southern
Baltic Sea
5
1.0
1.0
10
1.5
1.5
50
1.6
1.9
100
1.7
2.1
Lateral ice loads should be assumed to act in the same direction as thewind loads. Either
the high or low water level, with the necessary return period, should be assumed in
combinationwith ice loads. The combinationwith themost unfavourable effects governs.
The characteristic compressive strength of ice
s
0,k
depends on the ambient conditions
at the location, for example the local salt content of the seawater. Table 2.16 lists
reference values.
According to [26], the horizontal ice load for a compression failure due to drifting ice
acting on vertical piles, irrespective of their cross-sectional form, is calculated as
follows:
36
s
0
;
k
d
0
:
5
h
1
:
1
F
0
;
k
¼
0
:
½
kN
where
d width of single pile [cm]
h thickness of ice [cm]
Tests have shown that the compressive strength of the ice reaches its maximum value at
the specific rate of expansion
e
¼
0.003 s
1
, which is the value used here. If the case of
the start of the ice movement for firmly attached ice has to be considered, then
according to [26], other loading assumptions apply.
The characteristic local ice pressure acting on the surface of a structural member due to
incident drifting ice should be taken as follows [24]:
s
t
k
A
local
s
local
;
k
¼ s
0
;
k
1
þ
5
where
s
0,k
characteristic compressive strength of ice (s. Table 2.16)
t
k
characteristic thickness of ice
A
local
area on which the ice load acts
