progressive collapse in opensees

[moshtagh]

hi every bodi
does any body have cods about progressive collapse?
its aboute remove a member and analuse the structure
any body can help me?

[yas]

hi
I need progressive collapse codes too. if anyone have some information about this or have a file,please help me.
thanks

[vesna]

To remove a member you can use remove element command: http://opensees.berkeley.edu/wiki/index ... ve_Command

For this to work you need to remove all recorders and load patterns associated with this element.

[yas]

thanks for your helping,but I have some problems again.after introducing sections and material of the frame,I should import the loads and earthquake records,then determining kind of analysis,after that removing the element and determining the period of time we need to omit that ,then imposing the axial load of that removing element to other elements of the bay.then analyzing the frame with the past record of earthquake.are these steps true??
I have some questions too.my model is an steel frame with eccentrically braces.there is hinged connection where braces have connected to beams.so their beams has been divided to three elements.now should I import mass and load forces to the nodes of every three elements separately ?
I appreciate in advance.

[vesna]

I am not sure I understand your question. Would you please restate it?

Note: if your remove the element, nodes are still there. If you only had nodal loads, there is no need to modify this load after you remove the element.

[yas]

hi
Thanks for your paying attention to my question vesna.Its based on progressive collapse guidelines that when you remove an element you must import It,s loads to other elements of that bay.and now I have some problems with orders of that and I don,t know how to introduce the time history file for it,s analyzing?Should I make a file in seismosignal like Sap or not?

[vesna]

If you have element loads on the elements you are removing, after you remove elements and the element load define nodal loads that correspond to that load.

[yas]

hi dear vesna
for removing columns in progressive collapse based on GSA or UFC guidelines, Should I write an algorithm for that ?
I mean introduce a hinge for that column and compare displacement of that column with allowable amount?
thanks

[yas]

hello
I,m working on progressive collapse analysis of eccentrically braced frames
and could you help me to find an experimental example for my model?
thanks

[yas]

hi everyone
I,m having problem with choosing type of element.I,m working on progressive collapse in eccentrically braced frame and I don,t know use nonlinearBeamColumn or dispBeamColumn for that ? and I also don,t know use fatigue material or steel02 ?

I will appreciate if you help me .

[yas]

hello everybody
after removing element in progressive collapse does it need to remove its loads or the loads is removed by removing the element and redistribute the load to the other elements?
thanks in advance

[fmk]

if the element has loads applied to it directly, i.e. eleLoads then they must be removed otherwise the program will crash. loads that the element has been transferring to the supports via the load path will be redistribued in the next analysis step (basically on removal the nodes will now be in a state of unbalance which the next analysis step will hopefully be able to sort out!)

[yas]

thanks for your reply to my question dear fmk,
in my model the column and the brace I,ve removed doesn,t have ele loads or doesn,t have applied loads directly,so only removing the element is enough,is that true?

[fmk]

yes

[yas]

hello everybody
I,m studying about progressive collapse in eccentrically braced frame,and I,ve wrote some codes to remove the elements based on below :

In nonlinear dynamic analyses the gravity loads were linearly increased during 5 s to reach the final values, after that, they were kept unchanged for 2 s to avoid exciting dynamic effects. Once the gravity loads were fully applied at duration of 7 s, one column and connected brace were suddenly
removed, and afterward the subsequent response of the braced frame was investigated.would you please read this and give me some advices to complete it?.specially when gravity loads are kept unchanged for 2 s and I think this part of that is wrong in my codes.

I appreciate in advance



set Factor 1
set dt 0.01

# Total Steps
set Nstep 1000

# First Linear Loading Steps
set InitStep 500

# Number of Constant Load Steps ( Note: Sum of IntStep & ConctStep has to be less than Nstep )
set ConstStep 200

# Remove Element Step ( Note: Smaller than Total Steps )
set RemoveStep 700

# Element to be removed
set RemovedEle1 1
set RemovedEle2 86




################################################

puts " Model Has Been Defined "

source 5story-3bay.tcl

set FileName "data"
file mkdir $FileName


######## Recorders ###########

#### Note: you can not have a recorder for removed element ####


recorder Element -file $FileName/Col3.txt -time -ele 2 globalForce
recorder Element -file $FileName/Col4.txt -time -ele 3 globalForce
recorder Element -file $FileName/Col5.txt -time -ele 4 globalForce


set accelSeries "Series -dt $dt -filePath Elcentro-180_PGA=0.313g-dt0-01-pnt4000.txt -factor [expr $Factor*9.81]"
pattern UniformExcitation 2 1 -accel $accelSeries

set Tot [expr $InitStep+$ConstStep ]


for { set j 1 } { $j <= $Nstep } { incr j 1 } { ;

if { $j <= $InitStep } {


constraints Transformation ;
numberer RCM ;
system SparseGeneral ;
test EnergyIncr 1e-7 25 0 ;
algorithm ModifiedNewton ;
integrator Newmark 0.5 0.25 ;
analysis Transient ;
analyze 1 0.001 ;

}

if { $j > $InitStep } {

if { $j < $Tot } {
constraints Transformation ;
numberer RCM ;
system SparseGeneral ;
test EnergyIncr 1e-7 25 0 ;
algorithm ModifiedNewton ;
integrator Newmark 0.5 0.25 ;
analysis Transient ;
analyze 1 0.001 ;
}

if { $j >= $Tot } {

if { $j < $RemoveStep } {
constraints Transformation ;
numberer RCM ;
system SparseGeneral ;
test EnergyIncr 1e-7 25 ;
algorithm ModifiedNewton ;
integrator LoadControl [expr 1.0/$Nstep] ;
analysis Static ;
analyze 1 ;
loadConst

}

if { $j >= $RemoveStep } {

remove element $RemovedEle1
remove element $RemovedEle2

constraints Transformation ;
numberer RCM ;
system SparseGeneral ;
test EnergyIncr 1e-7 25 0 ;
algorithm ModifiedNewton ;
integrator Newmark 0.5 0.25 ;
analysis Transient ;
analyze 1 0.001 ;
}
}
}
puts "Step is $j"
}


puts " "
puts " "
puts "******************************************************************"
puts "* Multiple Time History Analysis Have Been Performed Succesfully *"