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The easy way is to check the inter-story drift for unexpectedly large values.
The hard way is to calculate and compare the input energy and the dissipated energy: They are almost equal to each other, until gravity takes over...

Hi, I do this by counting the records in the acceleration data file with the following four lines: set fp [open $THFileName r] set THData [split [read $fp] "\n"] set StepN [llength $THData] close $fp $THFileName is the file with the acceleration history records $StepN is the number of records in the...

I 'll try to be more specific: Sections 1&6 correspond to the ends I&J of the element Sections 2&5 correspond to the integration points at a distance of 8/3Lp from the ends Sections 3&4 seem to be located even further from the ends. I worked out their location as following: L=3.1542*βi-0.8448*bj+0.2...

Hello everybody!

As I understand, FB elements with HingeRadau integration method have 5 integration points and 6 output sections.
What is the location of each output section?

Thank you for your reply, you have been most helpful.

Indeed, I am using Lobatto. I always compare the curvatures at the first and the last section of the element. (command: [lindex [eleResponse $i section 1 deformation] 1] -for the first section) I understand that Radau is considered more accurate, but I 'd prefer a method which calculates internally ...

I am using forcebeamcolumn elements to model the columns of a RC structure, for performing NL IDA analysis. Subsequently, I use the curvature at the ends of the columns (sections 1 & N) to calculate a damage index. However, I am greatly concerned about the variation of the curvature values calculate...

Now that you mention it, I used "constraints Plain" for the static analysis, and "constraints Transformation" for the transient one. If I use "constraints Plain" in both analyses, there is no problem at all. And if I use "constraints Transformation" in both cases, the analysis gets clearly erroneous...

I haven't tried to built a 3d model, I am still dealing with 2d models only, but I have no doubt that the truss method will work in 3d models.
However, I am interested in why the aforementioned behaviour of the equalDOF diaphragm model occurs.

It is a 2d 3dof RC FBE frame model. The following is a 3 node example of what I am doing: # main nodes. columns are connected to them. node 2 0.00 3.00 node 9 4.50 3.00 #d iaphragm equalDOF 2 9 1 # floating node, same position as node 9, for the free beam end (beam connects between 2-209) node 209 4...

I suppose it is possible to do this using two patches, one for the flange and one for the web: section Fiber 1 { patch quad 1 12 6 -6 -3 3 -3 3 3 -6 3 patch quad 1 3 24 3 -15 9 -15 9 15 9 3 layer straight ... } In the above example, the cords 0,0 correspond to the centre of gravity. Someone more exp...

Thanks for your kind response! I am completely puzzled: I have tried Newton, ModifiedNewton, ModifiedNewton -initial, KrylovNewton, all with test NormDispIncr 1.0E-9 20 0 2 In every analysis, the first step fails, and the error trapping routine takes over. Always, this first step gets solved with th...

Finally I chose to use rigid diaphragms (equalDOF) and release the axial DOF at one end of the beams. (two different equalDOF commands, one for the horizontal DOFs of the main nodes, and one for the vert. + rot. of the secondary) I use this model for running IDA with many different records, in total...

Thank you so much! I added a node recorder and it worked perfectly. But, isn't it weird for nodeReaction to have the need of an other command to be enabled? I also noticed that while the bare "reaction" is not recognized as a command in the script, it is not rejected as "invalid command name" when i...

Hi everybody!

I am trying to use the command nodeReaction $node <-$DOF> for calculating the base reaction of a 2d model, but it returns zero forces at every node of the model (fixed or not). In fact, it returns zero forces in every node, in any model I make...

Any suggestion?