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# Defines Axial Spring
# Units: kip, in
# KJE, Feb 2003
set Fsw [expr 11.87/1.0]
# Axial elastic stiffness (only one axial spring used)
set axialElasticSlope [expr 99.0*$Ec*$A/$L]; #99 times more rigid than column
set axialNegSlope -90.0; #slope = axial load/axial displ}
# residual capacity
set Pr 5.0;
# axial loads used for setting initial elastic slope
set P1 65.0;
set P2 75.0;
set P3 85.0;
# define limit surface
# tag eleTag Fsw Kdeg Fres defType forType nodeI nodeJ dof perpDir delta eleRemove
limitCurve Axial $axialCurveTag $bcTag $Fsw $axialNegSlope $Pr 2 2 1 4 1 2 0.0 0
# define LimitStateMaterial
uniaxialMaterial LimitState $axialFailTag\
$P1 [expr $P1/$axialElasticSlope] $P2 [expr $P2/$axialElasticSlope] $P3 [expr $P3/$axialElasticSlope]\
[expr -$P1] [expr -$P1/$axialElasticSlope] [expr -$P2] [expr -$P2/$axialElasticSlope] [expr -$P3] [expr -$P3/$axialElasticSlope]\
0.5 0.5 0.0 0.0 0.0 $axialCurveTag 1