Chapter V
Hydraulic Performance
66
Table V-6 Formulas for Calculating Wave Run-Down
Formulas
Paramaters
On straight smooth slopes:
í µí±¹ í µí² í µí¿%
í µí±¯ í µí²
=0.33í µí¼ í µí²
for 0<í µí¼ í µí² <4
í µí±¹ í µí² í µí¿%
í µí±¯ í µí²
=1.5
forí µí¼ í µí² ≥4
í µí± í µí±2% : the run-down exceeded by 2% of waves.
í µí± í µí±1% : the run-down exceeded by 1% of waves.
í µí°» í µí± : Significant wave height at the toe of the
structure.
í µí¼ í µí± : breaker parameter based on í µí± í µí±
í µí± : notional permeability of the structure.
í µí± om : wave steepness with Lo, based on Tm
í µí± í µí± : the mean energy wave period.
í µí»¼ : the slope angle (°).
On porous rubble slopes:
By Thompson and Shuttler (1975):
í µí±¹ í µí² í µí¿%
í µí±¯ í µí²
=0.34í µí¼ í µí² −0.17
By Van der Meer (1988b) :
í µí±¹ í µí² í µí¿%
í µí±¯ í µí²
=2.1√í µí²í µí²í µí²í µí¼¶ − 1.2í µí±·
í µí¿.í µí¿í µí¿
+1.5 í µí±
(−60í µí± om )
Run-down Calculation Results
The results from Table V-7 and Table V-8 show that on average, the run-down height for the
Marina is 1.63 m, while it is 2.5 m for the Port. Considering that the toe of the main dike in the
Marina is located at a depth of 3 m, and the toe of the Khireddine jetty is at a depth of 10 m, we
can observe that for both main dikes, all run-down heights remain below the toe level ensuring
their protection.
By calculating the minimum extensions, we were able to identify the specific areas where wave
forces are exerted. It is noteworthy that the Marina's dikes typically experience wave forces
within a range of 6.2 m, whereas the port's dikes encounter forces over a distance of
approximately 10.4 m.
The cumulative impact of these forces and their application may pose risks to the stability of the
structure, primarily manifesting as internal erosion of the dike.
Table V-7 Run-down Calculation Results for Algiers Port Case
Return period
(year)
í µí±¯ í µí²í µí²
(m)
í µí±» í µí²
(s)
í µí½ í µí²
Rd2%
(m)
E
(m)
2 years
1.36
8.76
3.98
2.04
8.50
10 years
1.72
11.43
4.83
2.58
10.39
50 years
1.82
11.51
4.70
2.72
11.05
100 years
1.89
12.01
4.84
2.84
11.46
Table V-8 Run-down Calculation Results for Algiers Marina Case
Return period (year)
í µí±¯ í µí²í µí²
(m)
í µí±» í µí²
(s)
í µí½ í µí²
Rd2%
(m)
E
(m)
2 years
0.90
8.74
5.19
1.35
5.38
10 years
1.12
11.40
6.39
1.68
6.35
50 years
1.13
11.48
6.39
1.70
6.43
100 years
1.18
11.99
6.59
1.77
6.65
Hydraulic Performance
66
Table V-6 Formulas for Calculating Wave Run-Down
Formulas
Paramaters
On straight smooth slopes:
í µí±¹ í µí² í µí¿%
í µí±¯ í µí²
=0.33í µí¼ í µí²
for 0<í µí¼ í µí² <4
í µí±¹ í µí² í µí¿%
í µí±¯ í µí²
=1.5
forí µí¼ í µí² ≥4
í µí± í µí±2% : the run-down exceeded by 2% of waves.
í µí± í µí±1% : the run-down exceeded by 1% of waves.
í µí°» í µí± : Significant wave height at the toe of the
structure.
í µí¼ í µí± : breaker parameter based on í µí± í µí±
í µí± : notional permeability of the structure.
í µí± om : wave steepness with Lo, based on Tm
í µí± í µí± : the mean energy wave period.
í µí»¼ : the slope angle (°).
On porous rubble slopes:
By Thompson and Shuttler (1975):
í µí±¹ í µí² í µí¿%
í µí±¯ í µí²
=0.34í µí¼ í µí² −0.17
By Van der Meer (1988b) :
í µí±¹ í µí² í µí¿%
í µí±¯ í µí²
=2.1√í µí²í µí²í µí²í µí¼¶ − 1.2í µí±·
í µí¿.í µí¿í µí¿
+1.5 í µí±
(−60í µí± om )
Run-down Calculation Results
The results from Table V-7 and Table V-8 show that on average, the run-down height for the
Marina is 1.63 m, while it is 2.5 m for the Port. Considering that the toe of the main dike in the
Marina is located at a depth of 3 m, and the toe of the Khireddine jetty is at a depth of 10 m, we
can observe that for both main dikes, all run-down heights remain below the toe level ensuring
their protection.
By calculating the minimum extensions, we were able to identify the specific areas where wave
forces are exerted. It is noteworthy that the Marina's dikes typically experience wave forces
within a range of 6.2 m, whereas the port's dikes encounter forces over a distance of
approximately 10.4 m.
The cumulative impact of these forces and their application may pose risks to the stability of the
structure, primarily manifesting as internal erosion of the dike.
Table V-7 Run-down Calculation Results for Algiers Port Case
Return period
(year)
í µí±¯ í µí²í µí²
(m)
í µí±» í µí²
(s)
í µí½ í µí²
Rd2%
(m)
E
(m)
2 years
1.36
8.76
3.98
2.04
8.50
10 years
1.72
11.43
4.83
2.58
10.39
50 years
1.82
11.51
4.70
2.72
11.05
100 years
1.89
12.01
4.84
2.84
11.46
Table V-8 Run-down Calculation Results for Algiers Marina Case
Return period (year)
í µí±¯ í µí²í µí²
(m)
í µí±» í µí²
(s)
í µí½ í µí²
Rd2%
(m)
E
(m)
2 years
0.90
8.74
5.19
1.35
5.38
10 years
1.12
11.40
6.39
1.68
6.35
50 years
1.13
11.48
6.39
1.70
6.43
100 years
1.18
11.99
6.59
1.77
6.65