Study on transient and stationary response of jack-up platforms

This study investigates the effect of nonlinearities on the maximum response of Jack-up platform to waves. The total response incorporates two components, transient and stationary; which the transient response can be highly affected by the presence of some special wave periods depending on the period of the structure. Five foundation models including: perfect hinge and fix bases and more advanced models based on soil properties including linear springs & nonlinear springs with strain hardening plasticity models and a hinge base with linear rotational spring were incorporated in F.E models of structure. The effects of these support conditions on the maximum dynamic response are studied in detail.From the results of deterministic dynamic analysis for the waves with the heights ۰.۲۵ m to ۱۲.۲۵ m, it was concluded that change in the transient response are extremely dependent on the nonlinearity involved in the response which are due to numerous sources in the structural behavior such as geometrical, soil-structure-wave interactions.

Keywords:

jack up , stationary response , transient response , nonlinear dynamic behavior