Reinforcing Steel Material

Contact Authors:	Jon Mohle M.S., P.E.
	Sashi Kunnath: http://cee.engr.ucdavis.edu/faculty/kunnath/kunnath.htm

This command is used to construct a ReinforcingSteel uniaxial material object. This object is intended to be used in a reinforced concrete fiber section as the steel reinforcing material.

uniaxialMaterial ReinforcingSteel $matTag $fy $fu $Es $Esh $esh $eult < -GABuck $lsr $beta $r $gama > < -DMBuck $lsr < $alpha >> < -CMFatigue $Cf $alpha $Cd > < -IsoHard <$a1 <$limit> > >

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$matTag	integer tag identifying material
$matTag	unique material object integer tag
$fy	Yield stress in tension (see Figure 1)
$fu	Ultimate stress in tension
$Es	Initial elastic tangent
$Esh	Tangent at initial strain hardening
$esh	Strain corresponding to initial strain hardening
$eult	Strain at peak stress
-GABuck	Buckling Model Based on Gomes and Appleton (1997)

$lsr	Slenderness Ratio (see Figure 2)
$beta	Amplification factor for the buckled stress strain curve. (see Figure 3)
$r	Buckling reduction factor r can be a real number between [0.0 and 1.0] r=1.0 full reduction (no buckling) r=0.0 no reduction 0.0<r<1.0 linear interpolation between buckled and unbuckled curves
$gamma	Buckling constant (see Figures 3 and 4)

-DMBuck

Buckling model based on Dhakal and Maekawa (2002)

$lsr	Slenderness Ratio (see Figure 2)
$alpha	Adjustment Constant usually between 0.75 and 1.0 Default: alpha=1.0, this parameter is optional.

-CMFatigue

Coffin-Manson Fatigue and Strength Reduction

$Cf	Coffin-Manson constant C (see Figure 5)
$alpha	Coffin-Manson constant a (see Figure 5)
$Cd	Cyclic strength reduction constant (see Figure 6 and Equation 3)

-IsoHard

Isotropic Hardening / Diminishing Yield Plateau

$a1	Hardening constant (default = 4.3)
$limit	Limit for the reduction of the yield plateau. % of original plateau length to remain (0.01 < limit < 1.0 ) Limit =1.0, then no reduction takes place (default =0.01)

-MPCurveParams

Menegotto and Pinto Curve Parameters see Fig 6b

$R1	(default = 0.333)
$R2	(default = 18)
$R3	(default = 4)