| Structural reinforcement and repair has always been a hot issue in structural engineering academia,and the research on reinforcement mechanism is the most important one.In this paper,the restraint mechanism of axially compressed concrete columns strengthened with PET tape(plastic steel strip)is studied,which can provide guidance for practical reinforcement engineering design.Four groups of reinforced concrete columns strengthened with PET tape were tested under axial compression.The bearing capacity,ductility and failure modes of reinforced concrete columns strengthened with different PET tapes under the same prestress were compared and analyzed,and the stress characteristics and strain variation law of PET tapes were studied.The nonlinear finite element model of the specimen is established by ABAQUS finite element software,and the reliability of the numerical model is verified by comparing the finite element calculation results with the experimental results In order to eliminate the influence of out-of-plane stress,the corresponding calculation program was compiled by MATLAB software,and the maximum principal compressive stress distribution in each section was obtained.The influence range of steel cap constraint and the influence of angle steel on the constraint effect of PET tape were studied,and the influence of PET tape reinforcement spacing,layer number and specimen scale effect on the constraint mechanism was analyzed.On the basis of analyzing the existing constitutive model and failure mechanism of confined concrete,the calculation model of PET confined concrete column under axial compression is put forward,and the corresponding calculation formula is obtained.Compared with the calculation results of field test and finite element simulation model,the availability of the calculation formula is verified,which can provide theoretical guidance for practical engineering. |
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