The effect of shape on the failure envelope of the cross shaped foundation - Numerical Analyses

The paper presents the effects of different height to width ratios on the modification of the VH failure envelope of the so called cross-plate foundation (CSF), which has been presented in Nicolini & Castelletti (2017). The studies about this particular foundation are part of a wider research carried out to envisage a new offshore foundation system, prone to automated standardized construction and suitable to adapt to loads and geometry of the superstructures. The knowledge of the shape effect discussed in this paper is necessary to allow the design of a foundation system adapted to the local loads coming from the superstructure. After a brief introduction about the behaviour of the cross-shaped anchor, the paper will describe the selected modelling approach, based on the Finite Element Method, and conclude with the presentation and analysis of the shape of the obtained failure envelopes and of their modification as a function of the width and height of the plates. For one of the CSF shapes, the VHM diagram is also presented. Stresses in the steel structure of the foundation are calculated for all the investigated shapes and structural compatibility will be discussed.