A New Method For Calculating The Joint Design Parameters Under The Impact Of Typhoon Factors

Extreme sea conditions, such as wind speed, wave height, storm tide, ocean currents, etc., caused the severe damage and casualties of offshore, coastal engineering and coastal city, directly, and thereby caused huge economic losses. Moreover, various ocean engineering structures often suffered from the joint load effect of various sea conditions (wind, wave and flow, etc.), thus calculating the joint design standard reasonably affects the safety and the economy, directly. In recent years, the joint effect of various sea condition has been researched widely in the world.First of all, in typhoon-affected sea area, typhoon is the important cause of all sorts of marine disasters. So in order to overcome the shortcomings of the apriority existing in calculating design standard of extreme sea condition and to consider the other typhoon factors affecting sea condition, this paper deduced the 2-dimensional compound model to calculate the design parameter. The new model is based on measure theory, multivariate extreme value theory, variation theory, and etc., and considers two typhoon factors—typhoon occurring frequency and typhoon intensity. Secondly, in the analysis on the probability characteristic of two typhoon factors, this paper deduced that 2-dimensional discrete maximum entropy distribution. This distribution function can fully respect the objectively practical situation, and make full use of the known observation data. In addition, it has 6 parameters which can be solved by 6 equations obtained by moment method, and thus it is more flexible. Finally, Because the storm tide, which is caused by the impact of typhoon, causes the most serious disaster of casualties and property, and wave height and water level are more intuitive and important to ocean utility, this paper selects the wave height and water level as two continuous variable. In this paper, the joint distribution function is obtained based on the Copula method.To examine the new 2-dimensional compound model, this paper used it to calculate the joint design parameters of wave height and wave level of Chaoliao Island, so as to provide the relevant department with a new method for calculating design parameters.