Analysis of a Bending-Stressed Pile in Interaction with Subsoil

Abstract

This study explored reinforced concrete piles located in a flexible half-space and loaded with external loads, considering various contact elements and the connection between the pile and the ground massif. Piles are mainly solved as axially loaded elements stressed by a vertical force. However, there are also several cases in the construction industry where a pile is stressed by a horizontal force or by a bending moment, producing a bending loaded pile. A static model of a pile and the surrounding subsoil was constructed using software based on FEM. The pile was modelled from 3D finite elements that were rotationally symmetric around the vertical axis of the pile. Additionally, the flexible half-space was modelled from 3D elements that were rotationally symmetrical around the piles. The boundary conditions were applied on the surfaces around the perimeter and at the bottom of the ground massif. The flexible half-space was modelled up to the area where there was zero deformation. The presented analysis focused on the description of different types of contact elements between the surface of the reinforced concrete pile and the surrounding ground mass. This interaction was modelled as a fixed connection or as point-to-point contact, and a contact surface. In the next part, different boundary conditions on the pile bottom were considered. Floating piles, supported by joints or firmly woven into the ground massif, were considered. All these outputs based on FEM were compared with the analytical solution of the bent pile that was published in the 1980s. The deformations and internal forces during different modelling of the contact between the edge of the concrete pile and the surrounding ground mass were compared. The higher values of the studied quantities were for rigid connections, which is logical. For contact elements, the property of the contact was considered. This property introduces less stiffness, and thus, the resulting values were lower compared to those for a fixed connection. The presented analysis of the FEM analytical and numerical solution is also very valuable for engineers working in construction.