Dilation model and stress-strain relationships of CFRP tubesconf ining concrete columns under axial compression

Based on experimental result s , a dilation model of CFRP tubes confining concrete columns under axialcompression is set up. By use of the calculating variation regulation of confining pressure from the dilation model ,the constitutive model of axial compression of active confinement concrete columns and the failure criterion of concrete under multi-axial st ress , the theoretical expression of st ress-st rain relationships of axial compression for thepassive confinement concrete columns is derived. According to the properties , the content s , the st ress dist ributionunder axial compression of every component and the deformation equations , the constitutive relationships of CFRPtubes confining concrete columns under axial compression are found. The experiment s demonst rate that the predicted result s of the theory are quite identical with the experimental results.