Dynamic Analyses of Jacket Type Offshore Platforms against Progressive Collapse Considering Pile-Soil-Structure Interaction

Abstract

Article History: Received: 19 Jun. 2019 Accepted: 17 Sep. 2019 This research aims to present a practical framework to study the structural response of a jacket type offshore platforms subjected to a sudden member removal considering the pile-soil-structure interaction. To this end, a series of nonlinear dynamic analyses are performed, and the progressive collapse resistance of the generic structure is determined. Consequently, the members prone to failure are detected. As a case study, the application of the proposed framework to control the capability of these type of structures for the prevention of progressive collapse occurrence are investigated. In the model structure, some legs and vertical braces in different locations are eliminated, and the effect of each damage case on the performance of the structure is investigated while the environmental wind and wave loads are imposed to the platform. The simulation results demonstrated that although the jacket structure can sustain the loss of primary members safely, it is susceptible to failure progression while a leg and the connected brace are eliminated simultaneously. The safety margin, in this case, is about 20% only. In addition, it was revealed that in the case in which a leg and the connected brace are eliminated, progressive collapse resistance is about a third in comparison with the case of a leg damaged only.