Nonlinear finite element analysis of circular concrete-filled steel tube structures

Tengfei Xu, Tianyu Xiang, Renda Zhao and Yulin Zhan

Abstract

The structural behaviors of circular concrete filled steel tube (CFT) structures are investigated by nonlinear finite element method. An efficient three-dimensional (3D) degenerated beam element is adopted. Based on those previous studies, a modified stress-strain relationship for confined concrete which introduces the influence of eccentricity on confining stress is presented. Updated Lagrange formulation is used to consider the geometrical nonlinearity induced by large deformation effect. The nonlinear behaviors of CFT structures are investigated, and the accuracy of the proposed constitutive model for confined concrete is mainly concerned. The results demonstrate that the confining effect in CFT elements subjected to combining action of axial force and bending moment is far sophisticated than that in axial loaded columns, and an appropriate evaluation about this effect may be important for nonlinear numerical simulation of CFT structures.

Key Words

concrete-filled steel tube; nonlinear finite element analysis; degenerated beam element; updated lagrange formulation.

Address

Tengfei Xu: Department of Bridge Engineering, Southwest Jiaotong University, Chengdu 610031, P.R. China Tianyu Xiang: Department of Bridge Engineering, Southwest Jiaotong University, Chengdu 610031, P.R. China Renda Zhao: Department of Bridge Engineering, Southwest Jiaotong University, Chengdu 610031, P.R. China Yulin Zhan: Department of Bridge Engineering, Southwest Jiaotong University, Chengdu 610031, P.R. China

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