Study Of Environmental Multi-loads Combination For Jacket Platform Design In The Bohai Area

As the process of economization accelerated, an increasing demand for oil causesthat the oil mined on land can not meet the social needs. As a consequence, offshoreoil exploration which requests the help of marine structures is becoming more andmore important in industry. Therefore, it is necessary to study the response of marinestructures and the design of environmental loads on ocean platforms.This paper presents the ocean environmental elements of Chengdao, includingwind, waves and currents, as the rudimentary knowledge for the following research onjacket platform in Bohai Sea. In term of methodologies, the theory ANSYS modelingand load application is introduced and the first one is utilized to establish a certainjacket platform in Bohai Sea, while the later one is used in the calculation of structuralresponse of the platform, such as base shear, base bending moment and the maximumdisplacement of the deck, under various environmental loads. On the basis of aboveanalysis, the relationship between structural response and environmental loads wouldbe beneficial for the design of platform. Therefore, four new expressions are proposedin this paper. These methods are compared with the existing methods through errorsbetween the simulations and field data. Results illustrate that the deviations of twonew formulas are smaller than the pro-existing methods. In other words, the twoformulas are recommended to use as their accurate calculation.This paper illustrates the construction of three dimensional Gumbel model basedon the wind speed, velocity and wave height observed in Bohai Sea. Based on the newformulas, the maximum response of the platform and its relevant environmentalvariables corresponding to certain return period are calculated through MATLABprogram. So the most unfavorable load combination can be provided as the referencefor the design of offshore platforms. The result of joint joint design criteria ofenvironmental loads are compared with that of traditional design standard whichregards all the environmental elements as independent variables. The new method ofcalculation joint return periods reflects the joint behavior of wind speed, wave height and currents. Using this method, the maximum displacement, base shear and bendingmoment drop decreases to some extent.