The Sirri jacket offshore platform was designed and installed in Persian gulf of Iran in 1975 and has been in service since that time. The importance of offshore structure's stability and the failure of this kind of structure during an earthquake in different active zones revealed that earthquake loading has to be considered. In this paper, Magnetorheological (MR) fluid dampers have been propos...

In the structural optimization problem, the aim is to decrease the amount of structural costs and weight, but the safety of platform should not violate the individual limits enforced by offshore codes. The outer diameter and thickness of members are two important variables in the optimization process and their final dimensions should be obtained according to the optimization algorithms such as ...

Regarding the previous earthquake damages in offshore structures, as vital structures in the oil and gas industries, it is important that their seismic design will be performed with very high reliability. Accepting the Nonlinear Time History Analyses (NLTHA) as the most reliable seismic analysis method, in this paper an offshore platform of jacket type with the height of 304 feet and with a dec...

Development of a numerical model which describes launching of offshore jackets from barge is presented in this paper. In this model, in addition to capabilities of commercial softwares, water entry forces on jacket members and an implicit Newmark solution technique are included. The results are in general agreement with other numerical software’s available (SACS). Fluid forces acting on jacket ...

The irregular wave disturbance attenuation problem for jacket-type offshore platforms involving the nonlinear characteristics is studied. The main contribution is that a digital-control-based approximation of optimal wave disturbances attenuation controller (AOWDAC) is proposed based on iteration control theory, which consists of a feedback item of offshore state, a feedforward item of wave for...

marine industry requires continued development of new technologies in order to produce oil. an essential requirement in design is to be able to compare experimental data from prototype structures with predicted information from a corresponding analytical finite element model. in this study, structural model updating may be defined as the fit of an existing analytical model in the light of measu...

The vibration control problem of offshore jacket platforms is studied. According to Morison equation, the total wave force acting on the offshore structure is obtained and is generated by an exosystem. Considering the nonlinear interaction of pile-soil, which is described by a fifth order anti-symmetric polynomial, the nonlinear dynamical model of offshore platforms affected by the wave load di...

in this paper, pile behavior embedded in layered soil deposits subjected to seismic loadings is analyzed using a nonlinear fiber element for simulation of soil – pile interactions. in the created model, both pile and surrounding soil are modeled using fiber elements in a practical beam on nonlinear winkler foundation (bnwf) concept. herein, the features of drain–3dx finite element software are ...

Effect of earthquake directional uncertainty on the seismic response jacket-type offshore platform