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# define structure-geometry parameters set NStories 6; # number of stories set NBays 5; # number of frame bays (excludes bay for P-delta column) set LBeam [expr 20.0*12.0]; # bay width in inches set LCol1 [expr 17.5*12.0]; # 1st story height in inches set LCol [expr 13.0*12.0]; # story height of oth...

thanks for the references. The example on opensees wiki, the 2-story moment frame (http://opensees.berkeley.edu/wiki/index.php/MRF_2Story_Concentrated.tcl) has a comment next to ascribing a large I to the leaning columns: "# moment of inertia for p-delta columns (make much larger than I of fram...

Thanks Frank, Would imparting Rayleigh damping to all elements of the model (elements from the frame, the zero length elements, and the elements from the leaning column (truss links and the elastic beam-column)) vs imparting only to the members of the main frame (the way it is done in the 2-story ex...

Hi, I have a few questions about leaning column. Can leaning column be used in combination with any elements in the main frame. For instance, is it okay to use beamwithhinge for my beams and columns. I have seen some comments that displacement-based elements are easier to combine with leaning column...

Amir, Once you assign damping to in terms of kcommit (which is the tangent stiffness changing according to the time series (as load) in your dynamic nonlinear analysis), the code itself changes it at every time step after it converges. once the convergence is achieved, then the program uses this sti...

Hi Vesna, I beg to differ: if you look at my formulation, it exactly ends up with beta coefficient being 2 * damping coef / omega, and then the damping is that quantity times the tangent stiffness (or Kcommit). which ends up exactly as "c=$betaKcomm*$Kcomm" with $betaKcomm = 2 * damping co...

Hi Amir, When you define your Rayleigh damping, then the damping setup will be imparted to all previously defined elements. If you want your damping to be calculated as the stiffness is changed (during the inelastic cycles), then you use the Kcommit stiffness and set the other stiffness quantities e...

thanks for you quick response. But how come I have seen codes for SDOF posted by Silvia (http://opensees.berkeley.edu/community/viewtopic.php?p=4014) which specifies tangent-stiffness damping only for SDOF (i.e., no mass-proportion). Also i thought if i only specify tangent-stiffness proportional co...

Hi there, 1. How does Opensees handle Rayleigh damping for single degree of freedom system? Rayleigh damping requires two frequencies to be completely defined. 2. Both posted examples and some of the answers to forum posting uses Rayleigh damping for SDOF systems. 3. Most recommended Rayleigh dampin...

Can i use steel01 material with beamwithHinge element?
thanks

Hi, When i use steel01 to define uniaxial material for beamwithhinge element, i do converge. but when i use uniaxial Bilin i can't even get passed the first increment of static analysis. I have tried Lp from 0.05 of element length to 0.004*element length (as was coded in an opensees example). Does a...