Numerical Analysis on the Bending Capacity of the Concrete-Filled Micro-Steel-Tube Piles

Abstract

The finite element analysis model is developed to investigate the bending capacity of the concrete-filled micro-steel-tube (CFMST) piles. First, the classical elastic-plastic model is employed to describe the constitutive relation of the steel material, while the plastic damage model is applied to portray the concrete material. Then, the three dimensional (3D) finite element numerical model for analyzing the flexural bearing capacity of the CFMST pile is established by virtue of the ABAQUS software. The reliability and accuracy of the present numerical model is carefully validated by comparing with the experimental data. The influence of the concrete strength grade, wall thickness of the steel tube, external diameter of the steel tube, and yield strength of the steel are analyzed in detail. It is shown that increasing the wall thickness/external diameter of the steel tube and the yield strength of the steel can greatly improve the flexural bearing capacity of the CFMST pile. Finally, a concise formula for the ultimate bending moment of the CFMST pile is proposed, which could be directly applied into the future engineering design.