# 4.14.2.3. Concrete04¶

uniaxialMaterial('Concrete04', matTag, fc, epsc, epscu, Ec, fct, et, beta)

This command is used to construct a uniaxial Popovics concrete material object with degraded linear unloading/reloading stiffness according to the work of Karsan-Jirsa and tensile strength with exponential decay.

 matTag (int) integer tag identifying material fc (float) floating point values defining concrete compressive strength at 28 days (compression is negative) epsc (float) floating point values defining concrete strain at maximum strength epscu (float) floating point values defining concrete strain at crushing strength Ec (float) floating point values defining initial stiffness fct (float) floating point value defining the maximum tensile strength of concrete (optional) et (float) floating point value defining ultimate tensile strain of concrete (optional) beta (float) loating point value defining the exponential curve parameter to define the residual stress (as a factor of ft) at etu

Note

1. Compressive concrete parameters should be input as negative values.
2. The envelope of the compressive stress-strain response is defined using the model proposed by Popovics (1973). If the user defines $$Ec = 57000*sqrt(|fcc|)$$ (in psi)’ then the envelope curve is identical to proposed by Mander et al. (1988).