Capacity envelope of plate anchors under six degree-of-freedom loads in clay

Abstract

The capacity envelope of plate anchors has been established for two-dimensional case under 3 degree-of-freedom (DOF) loads, while there is limited knowledge about three-dimensional (3D) plate anchors subjected to 6 DOF loads. This paper investigates the capacities of plate anchors in 3D case through finite element modelling. A square plate anchor is first considered with 246 finite element analyses conducted under uniaxial, 2 DOF, 3 DOF and 6 DOF loads, respectively. The effect of aspect ratio on the uniaxial capacities is analysed by considering rectangular plate anchor. A 6 DOF capacity envelope is obtained by fitting a rigorous sum of squares convex polynomial equation. By analysing the correlation degree of 6 DOF loads and parameters of the polynomial equation, an easy-to-use power law equation of 6 DOF capacity envelope is developed. This simple equation is employed in a force-resultant plasticity model to predict 3D kinematics of plate anchor under 6 DOF loads. A calculation case study is then presented to demonstrate the anchor behaviour in 3D space.