The study on sensibility of self-elevating unit legs strength to different bay heights under storm environment condition

Legs are the main load-carrying structures of Self-elevating Unit. To optimize leg structure can improve unit environmental bearing capacity. Aiming at studying on the truss legs optimum design, the paper analyzes the sensibility of leg strength to different bay height under storm condition. It obtains wind loads from wind Tunnel Test. Based on STOKES 5 orders wave theory and Morison equation, the wave and current loads are obtained by WAJAC, calculation software of SESAM developed by DNV. It obtains the inertial load considering the DAF factor through the natural vibration period and It obtains the inertial moment considering the P-A effect through one order offset value, the results are all calculated by eigenvalue analysis. This paper emphasizes on checking structure strength by the above calculation results and gives the most optimal value of bay height for legs. It also makes up the sensitivity analysis technique of bay heights, and it can provide reference for the self design for Key parts of self-elevating unit.