A structure must be dimensioned for the highest value of the wave forces and moments. The wave height Hs has a stochastic character. However, the problem can be solved by dimensioning for a load that has an acceptable exceedence probability per storm.

Horizontal force on a vertical wall according to Sainflou:

With:

and

Symbols used in this help:

• Cf = resistance coefficient = ca. 0.01 [-]
• c = propagation velocity of the waves without current [m/s]
• c' = propagation velocity of the waves in relation to a land based coordinate system with current [m/s]
• cg = wave train velocity [m/s]
• E = total average wave energy per unit of area [Nm/m2 = J/m2]
• F = average energy-transfer in the direction of propagation per time and per width [W/m]
• H = wave height [m]
• H1 = wave height at starting point [m]
• H2 = wave height at starting point + Äx [m]
• h = average water depth [m]
• hc = distance between slack water line and the top of the vertical wall [m]
• L = wave length [m]
• r = reflection coefficient [-]
• T = wave period [s]
• T' = apparent wave period with land based coordinates in the case of flow in the direction of the wave propagation [s]
• U = Ursell number [-]
• u = flow component in the direction of the wave propagation (positive in the direction of the waves) [m/s]
• x = horizontal coordinate in relation to the vertical wall with standing waves [m]
• z = vertical coordinate in relation to the average surface area of the water (positive above the surface of the water) [m]
• Dx = distance over which wave damping occurs [m]
• hmax = maximum deviation above SWL [m]
• r= density of the water [kg/m3]