Pile–soil-structure interaction in pushover analysis of jacket offshore platforms using fiber elements

Abstract In this paper, pushover analysis of fixed jacket offshore platforms with the application of “Fiber Elements” which are capable of modeling post-buckling behavior of braces has been conducted and case study on two functional jacket offshore platforms in the Persian Gulf region has been performed. Two-dimensional models of the mentioned platforms are simulated using “DRAIN-3DX” software and the wave force is considered as the lateral load pattern on the structures. In this paper, pushover analysis of jacket offshore platforms is performed by developing numerical models that incorporate different foundation conditions for considering pile–soil-structure interaction. Increasing the displacement of the platforms and recording the relative load factors by incorporating the displacement control method is the basis for performing the analysis. In order to consider the importance of pile–soil interaction, six individual cases are examined which include pile–soil interaction analysis with actual soil in-situ characteristics. Pile head fixed below mud line elevation, pile head hinged below mud line elevation, application of linear pile stubs, application of non-linear pile-stubs & finally a combination of linear and non-linear pile–soil characteristics. In the analyses performed herein, the condition in which pile–soil interaction is considered is set to be the base case. The results from incorporating the non-linear pile stub have the most compatibility with the base case. Application of Linear pile stubs and the combination of linear and non-linear pile has much deviation with the base case. Ultimate strength of the platform in the non-linear pile stub case was very close to the base case.