TWO-PARAMETER EXPONENTIAL CONSTITUTIVE MODEL WITH ADJUSTABLE SOFTENING MECHANISM FOR CONFINED CONCRETE

The softening characteristic of the constitutive model for confined concrete is vital for predicting the behavior of Concrete Filled steel Tube (CFT) columns. Based on 6 groups of experimental results for square CFTs under uniaxial compression, a two-parameter exponential constitutive model is proposed to depict the softening behavior of confined concrete. The width-to-thickness ratio, concrete strength and steel strength etc. of square CFTs are considered in the proposed constitutive model which simulates the softening behavior of confined concrete under different loading condition well. Based on the proposed confined concrete constitutive model, the overall failure process of 6 groups of square CFTs under uniaxial compression is calculated. The calculation results match the test reasonably.