Efficient numerical algorithms for assessing the mechanical performance of corroded offshore steel sheet piles

Abstract

Deterioration of offshore steel sheet pile walls subjected to corrosion may significantly affect the structural performance under serviceability and failure. Most steel corrosion studies focused on the mechanism of reflecting the actual corrosion situations to establish a relatively realistic corrosion model. The mechanical performances of the material loss phenomenon in the offshore steel sheet piles are useful for assessing their in-service and life cycle conditions. In this paper, the general power corrosion model is adopted to reflect the changes in the material and section properties of the pile and combine with the p-y curve method to formulate a new pile element to consider the corrosion effect. The Updated-Lagrangian (UL) method and the newly-developed element formulations are integrated into a modified Newton-Raphson method to eliminate the repetitive modelling process when considering the varied mechanical properties under different corrosion levels. After verifying the accuracy of the present numerical method, parametric studies have been considered to explore the effects of the changes of the annual corrosion rates and the trends of corrosion progress on the offshore steel sheet piles. The annual corrosion rate in the immersion zone plays an important role in the mechanical performance of offshore structures in a marine environment.