Nonlinear Finite Element Buckling Analysis of Square Reinforced Concrete long Columns Confined with Carbon Fiber Reinforced Plastic (CFRP) Sheets under Uniaxial Compression

Abstract

The general software ANSYS is adopted to establish the finite element models of square reinforced concrete long columns confined with CFRP sheets under uniaxial compression and used to analyze the influence of CFRP sheets to these structural buckling loads. Height of columns, layers of CFRP sheets, concrete grade, longitudinal rebar diameter, stirrup diameter and stirrup spacing are some factors considered. Based on the nonlinear finite element buckling analysis of these columns, some major conclusions are summarized as follows: (1) The enhanced level of buckling load is descending with the increasing columns’ height; (2) The buckling load is rising along with the increasing layers on a nonlinear manner; (3) The buckling load increment is independent of concrete grade, longitudinal rebar diameter, stirrup diameter and stirrup spacing; (4) The improvement is not very obvious to use CFRP sheets to strengthen the structure when it’s stability goes wrong. Influences of CFRP sheets to square reinforced concrete long columns can be found by analyzing the stability of these columns, and the analysis results are available for the strengthening of some structures.