A Question About nonlinearBeamColumn element

[rmandok]

Hi,
I have a question about element nonlinearBeamColumn command:

element nonlinearBeamColumn $eleTag $iNode $jNode $numIntgrPts $secTag $transfTag <-mass $massDens> <-iter $maxIters $tol>

I have a beam and i want to apply the mass uniformly in the same direction of my earthquake acceleration record, if i use -mass $massDens in this command would it affect in my earthquake record direction or it will applied at the same direction of gravity?!

[vesna]

If specified, mass density will be used to calculate translational lumped masses at the element ends. However, this option is not working properly at the moment. I would suggest you not to use it until the problem is resolved. Specify masses directly using mass command.

[rmandok]

Very very on time notation, Thanks.

[civil]

hi dear all

what is the differences between nonlinearBEamColumn (forceBeamColumn) and nonlinearBEamColumn (dispBeamColumn)? and how they influence on recorder and response of structure?
in selection each of them, which parameter should be considered? in fact i want to know which of them i should use in my model?

[fmk]

http://opensees.berkeley.edu/wiki/index ... ed_Element

[edwardal]

vesna wrote:
> If specified, mass density will be used to calculate translational lumped
> masses at the element ends. However, this option is not working properly at
> the moment. I would suggest you not to use it until the problem is
> resolved. Specify masses directly using mass command.

Was this issue with the mass density ever resolved? Currently, it seems that the mass from the element density is taken into account for an eigen analysis, but not for a transient analysis.

[fmk]

the element does not know reason it is being asked for it's damping matrix, so whether it is an eigenvalue analysis or a transient anaylsys the rMass matrix returned should be the same.

[venkateshyadav]

fmk wrote:
>
> http://opensees.berkeley.edu/wiki/index ... ed_Element

Hi,
I had read that file FBE VS DBE approach. I have modelled 2D single story RC frame using dispBC and forceBC elements for pushover analysis.
In fact I had subdivided each element into 5 elements for dispBC element, by that am getting Baseshear =52 KN and corresponding displacement as 57mm
and by using forceBC element am getting Baseshear= 41 KN and corresponding displacement as 36mm.
It is a huge variation in the results. Now am confused which element to be used for my further analysis.
I have to do pushover analysis for 3, 4 , 5 ,7 story RC frames, so I would like to know which element is preferred for Pushover analysis? and if dispBC is to be used how many divisions(meshing) to be done for getting better results?
Thanks in adavnce