is a typical component for supporting the tall bridge tower of the long-span bridge structure in deep water due to the advantage of large stiffness and easy construction. In deep water, the caisson foundation exhibits obvious wave diffraction characteristics when subjected to wave attack. Establishing a simple method to estimate the wave forces
acting on the caisson foundation is an important issue for en
gineers to assure the safety of the structures under wave action
As an example, the wave force and wave run-up of a quasi- ellipse caisson foundation of a cross-strait bridge pylon are analyzed by using the present method in this subsection. The schematic diagram of the foundation is shown in Fig. 15. The caisson foundation has an approximately elliptical section with dimensions of 60 m x 80 m, combining a central rectangle of
20 m x 60 m and two external half circles with radii of 30 m.
To employ the present method, the radius function of the quasi-ellipse cross section of the caisson foundation is first ex- panded into a Fourier series. As an example, Eq. (38) gives the
formula of the radius function in the case of α = 0o. Fig. 16 shows
the comparison of the actual shape of the curve of the cylinder
surface and the approximate fitting curves by the Fourier series with the truncated order of 2 and 14, respectively. From the figure, the expanded Fourier series can be effectively used to represent