The OpenSees Community

I am analyzing a 2D RC frame building in OpenSees (tcl). The members are force based nonlinear beam column element. The frame is subjected to a lateral load and columns are expected to fail in shear. The shear behavior is incorporated through section aggregator command. But how we will know that a column is failed in shear? Is there any specific warning which will appear, or we will get some kind of error?

Hi
I am analyzing a 2D RC frame under some lateral load. I want to record the shear force and bending moment (at both ends and 4 integration points) for a column on which the lateral UDL is applied. I have defined the recorders as follows:

recorder Element -file $dataDir/Moment1011sec3.out -time -ele 1011 section $np moment;
recorder Element -file $dataDir/Force1011sec3.out -time -ele 1011 section $np force;

But the moment recorder is not recording any response. And how we can record the shear force and bending moment at both ends of columns?

Thank you for your time.

Hi
I am analyzing a 4-story 2D RC frame under gravity followed by earthquake ground motion. All the columns as well the beams have same cross-section. However, I am getting "WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 2232(dW: << 0.201805)" for the beams of first story only. Is there some problem with the fibre section and element (nonlinearBeamColumn) I defined? Kindly help.

The time history code segment is as follows:
# Define time history load case
set Nsteps 3000
set DtAnalysis 0.01
set TmaxAnalysis [expr $Nsteps*$DtAnalysis];
set G 9.81
timeSeries Path 2 -dt 0.005 -filePath Northridge.tcl -factor $G; # define acceleration vector from file (dt=0.005 is associated with the input file gm)
pattern UniformExcitation 2 1 -accel 2; # define where and how (pattern tag, dof) acceleration is applied

# set damping based on first eigen mode
set zeta 0.05; # percentage of critical damping
set betaK [expr $zeta*2.0/($w1)]; # stiffness proportinal damping coefficient
rayleigh 0.0 0.0 0.0 $betaK ;# last committed stiffness is actually just the element’s tangent stiffness

constraints Transformation ; #Lagrange
numberer RCM ;
system UmfPack;#SparseGeneral;BandSPD;UmfPack ;BandGeneral
set Tol 1.e-8;
variable testTypeDynamic EnergyIncr;
test EnergyIncr $Tol 10;
algorithm Newton;# Newton-Raphson algorithm to solve the nonlinear residual equation

integrator Newmark 0.5 0.25 ;
analysis Transient ;
# analyze 3995 0.01;

set ok [analyze $Nsteps $DtAnalysis]; # apply 3995 0.01-sec time steps in analysis
if {$ok != 0} { ; # analysis was not successful.
set ok 0;
set controlTime [getTime];
while {$controlTime < $TmaxAnalysis && $ok == 0} {
set controlTime [getTime]
set ok [analyze 1 $DtAnalysis]
if {$ok != 0} {
puts "Trying Newton with Initial Tangent .."
test NormDispIncr $Tol 1000
algorithm Newton -initial
set ok [analyze 1 $DtAnalysis]
test EnergyIncr $Tol 10
algorithm Newton
}
if {$ok != 0} {
puts "Trying Broyden .."
algorithm Broyden 10
set ok [analyze 1 $DtAnalysis]
test EnergyIncr $Tol 10
algorithm Newton
}
if {$ok != 0} {
puts "Trying NewtonWithLineSearch .."
algorithm NewtonLineSearch 0.8; #0.8 is default tol
set ok [analyze 1 $DtAnalysis]
test EnergyIncr $Tol 10
algorithm Newton
}
if {$ok != 0} {
puts "Trying NewtonWithLineSearch .."
algorithm ModifiedNewton
set ok [analyze 1 $DtAnalysis]
test EnergyIncr $Tol 10
algorithm Newton
}
}
};