Experimental study on the wave run-up of a semi-submersible platform under regular waves

The study of Wave Run-Up (WRU) characteristics is important in the design of offshore platform. This paper concentrates on the semi-submersible platform with variable cross-section columns, and aimed to explore the influence association between wave run-up and wave parameters. A series of benchmark experiments with a scale (1:60) model were performed to explore the influence of wave period (T = 7s, 9s, 12s, 15s), wave steepness (kA = 0.11 and 0.21) and wave incident angle (180° and 135°). The results show that the wave period exerts key effect on WRU. Under 180° incident angle, the wave run-up has strong nonlinear characteristics around columns under short waves. The increase of wave steepness has a significant enhancement effect on WRU. Under 135° incident angle, the WRU decreases obviously and the influence of wave steepness become slight. The harmonic analysis reveals the excitation amplification effect of incident wave on wave run-up under 7s and 9s wave period. The excitation amplification effect of incident wave depends on the ratio of the amplitude of second harmonic component to fundamental harmonic component and the shallow water shoaling effect of pontoon. The short wave under 180° incident angle and high wave steepness is the main risk to semi-submersible platform. In addition, meaningful conclusions about the association between WRU characteristics and wave parameters were drawn in this paper. • A series of benchmark experiments with a scale (1:60) model were carried out. • The relationship between wave run-up and wave parameters is revealed.