Buckling restrained steel brace model - stl_brb

Stl_brb  is a uniaxial steel material model describing the behaviour of steel in Bucking Restrained Braces. The model has been presented by Zona et al. [2012]

Eleven model calibrating parameters must be defined in order to fully describe the mechanical characteristics of the material:

Modulus of elasticity -  Es
This is the initial elastic stiffness of the material. Its value usually oscillates between 200 and 210 GPa. The default value is 200 GPa.

Yield strength - fy
This is the stress at yield. Its value typically varies from 260 MPa up to 420 MPa. The default value is 375.4 MPa.

Maximum yield force for fully saturated isotropic hardening for tension  fy,max T
The default value is 581 GPa.

Constant controlling elastic to plastic transition for tension αt
The default value is 0.9.

Hardening ratio for tension bt
The default value is 0.01.

Constant controlling the isotropic hardening for tension δt
The default value is 0.2.

Maximum yield force for fully saturated isotropic hardening for compression fy,max C
The default value is 581 GPa.

Constant controlling elastic to plastic transition for compression αc
The default value is 0.9.

Hardening ratio for compression bc
The default value is 0.01.

Constant controlling isotropic hardening for compression δc
The default value is 0.2.

Specific weight -
This is the specific weight of the material. The default value is 78 kN/m3.