LimitState

This command is used to construct a uniaxial hysteretic material object with pinching of force and deformation, damage due to ductility and energy, and degraded unloading stiffness based on ductility. Failure of the material is defined by the associated Limit Curve.

uniaxialMaterial LimitState $matTag $s1p $e1p $s2p $e2p
        $s3p $e3p $s1n $e1n $s2n $e2n $s3n $e3n $pinchX $pinchY $damage1
        $damage2 $beta $curveTag $curveType.

matTag

integer tag identifying material

s1p e1p

stress and strain (or force & deformation) at first point of the envelope in the positive direction

s2p e2p

stress and strain (or force & deformation) at second point of the envelope in the positive direction

s3p e3p

stress and strain (or force & deformation) at third point of the envelope in the positive direction

s1n e1n

stress and strain (or force & deformation) at first point of the envelope in the negative direction*

s2n e2n

stress and strain (or force & deformation) at second point of the envelope in the negative direction*

s3n e3n

stress and strain (or force & deformation) at third point of the envelope in the negative direction*

pinchX

pinching factor for strain (or deformation) during reloading

pinchY

pinching factor for stress (or force) during reloading

damage1

damage due to ductility: D1(m-1)

damage2

damage due to energy: D2(Ei/Eult)

beta

power used to determine the degraded unloading stiffness based on ductility, m-b (optional, default=0.0)

curveTag

an integer tag for the Limit Curve defining the limit surface

curveType

an integer defining the type of LimitCurve (0 = no curve,

1 = axial curve, all other curves can be any other integer)

NOTES:

  • negative backbone points should be entered as negative numeric values

Examples

Original version of example:

Debugged version of example:

Manual for the example:


Description

Modeling Failures in Existing Reinforced Concrete Columns by Ken Elwood: file:ElwoodCJCE2004.pdf


References

Elwood, K.J and Moehle, J.P., “Shake Table Tests and Analystical Studies on the Gravity Load Collapse of Reinforced Concrete Frames”, Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA. PEER 2003/01.


Code Developed by: Ken Elwood, University of British Columbia

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