Limit State Material: Difference between revisions

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(Created page with '{{CommandManualMenu}} This command is used to construct a hyperbolic gap material object. {| | style="background:yellow; color:black; width:800px" | '''uniaxialMaterial Hyperb...')
 
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{{CommandManualMenu}}
{{CommandManualMenu}}


This command is used to construct a hyperbolic gap material object.
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]].
 
 


{|  
{|  
| style="background:yellow; color:black; width:800px" | '''uniaxialMaterial HyperbolicGapMaterial $matTag $Kmax $Kur $Rf $Fult $gap'''
| style="background:yellow; color:black; width:800px" | '''uniaxialMaterial LimitState $matTag $s1p $e1p $s2p $e2p $s3p $e3p $s1n $e1n $s2n $e2n $s3n $e3n $pinchX $pinchY
$damage1 $damage2 $beta $curveTag $curveType.'''
|}
|}


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|  style="width:150px" | '''$matTag ''' || integer tag identifying material
|  style="width:150px" | '''$matTag ''' || integer tag identifying material
|-
|-
|  '''$Kmax''' || initial stiffness
|  '''$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 $e3p''' || stress and strain (or force & deformation) at third point of the envelope in the positive direction
|-
|-
|  '''$Kur''' || unloading/reloading stiffness
|  '''$s1n $e1n''' || stress and strain (or force & deformation) at first point of the envelope in the negative direction*
|-
|-
|  '''$Rf''' || failure ratio
|  '''$s2n $e2n''' || stress and strain (or force & deformation) at second point of the envelope in the negative direction*
|-
|-
|  '''$Fult''' || ultimate (maximum) passive resistance*
|  '''$s3n $e3n''' || stress and strain (or force & deformation) at third point of the envelope in the negative direction*
|-
|-
|  '''$gap''' || initial gap*
|  '''$pinchX''' || pinching factor for strain (or deformation) during reloading
|}
|-
 
|  '''$pinchY''' || pinching factor for stress (or force) during reloading
 
|-
NOTES:
|  '''$damage1''' || damage due to ductility: D1(m-1)
 
*This material is implemented as a compression-only gap material. '''$Fult''' and '''$gap''' should be input as negative values.
* Recomended Values:
{|
|  style="width:80px" | '''$Kmax''' || = 20300 kN/m of abutment width
|-
|-
|  '''$Kcur''' || = $Kmax
|  '''$damage2''' || damage due to energy: D2(Ei/Eult)
|-
|-
| '''$Rf''' || = 0.7
| '''$beta''' || power used to determine the degraded unloading stiffness based on ductility, m-b (optional, default=0.0)
|-
|-
| '''$Fult''' || = -326 kN per meter of abutment width
| '''$curveTag''' || an integer tag for the [[LimitCurve]] defining the limit surface
|-
|-
| '''$gap''' || = -2.54 cm
| '''$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


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DESCRIPTION:
DESCRIPTION:


This file contains the class implementation for HyperbolicGapMaterial. This material is based on abutment stiffness models for bridge simulation proposed by Patrick Wilson and Ahmed Elgamal at UCSD. The abutment stiffness models are based on large-scale abutment tests performed on the outdoor shaking table at UCSD. The model is described for a 1.68 meter (5.5 ft) tall backwall height (typical size) and a 1 meter wide section along the width of the abutment (to be scaled accordingly). The hyperbolic force-displacement model is based on work by Duncan and Mokwa (2001) and Shamsabadi et al. (2007) with calibrated parameters from UCSD abutment tests. This model matches very well with test data up to 7.64 cm of longitudinal displacement.
[[file:ElwoodCJCE2004.pdf]]
 
:<math>F(x) = \frac{x}{\frac{1}{K_\text{max}} + R_f \frac{x}{F_\text{ult}}}</math>
 
 
[[Image:HyperbolicGapA.png]]
 
[[Image:HyperbolicGapB.png]]


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REFERENCES:
REFERENCES:


Duncan, J. M., and Mokwa, R. L. (2001). "Passive earth pressures: theories and tests." Journal of Geotechnical and Geoenvironmental Engineering, 127(3), 248-257.
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.
Shamsabadi, A., Rollins, K. M., and Kapuskar, M. (2007). "Nonlinear soil-abutment-bridge structure interaction for seismic performance-based design." Journal of Geotechnical and Geoenvironmental Engineering, 133(6), 707-720.
 
Wilson, P and Elgamal, A (2006).  "Large scale measurement of lateral earth pressure on bridge abutment back-wall subjected to static and dynamic loading."  Proceedings of the New Zealand Workshop on Geotechnical Earthquake Engineering, University of Canterbury, Christchurch, New Zealand:  pp 307-315.


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Code Developed by: <span style="color:blue"> Mathew Dryden, UC Berkeley</span> and <span style="color:blue"> Patrick Wilson, UCSD</span>
Code Developed by: <span style="color:blue"> Ken Elwood, University of British Columbia</span>

Revision as of 20:19, 23 March 2010



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 LimitCurve 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


DESCRIPTION:

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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