How to model Beams in Finite element software
How to model Beams in Finite element software
(OP)
Hey guys
I think I have one question ,that I suppose many people counter it before ,and I would like to see the best way to overcome it:
1.If we have columns in which their centers in Y direction are not on the same line,how I will be able to model the beam connecting them for example on etabs,the actual situation is that beam setting on the center of one column and the edge of the other columns ,however in etabs you can only model center to enter.(See the attached picture)
2.My first question is leading to my second question,if I model beam center to center ,I have to delete this part of slab that lies outside the beams
I think I have one question ,that I suppose many people counter it before ,and I would like to see the best way to overcome it:
1.If we have columns in which their centers in Y direction are not on the same line,how I will be able to model the beam connecting them for example on etabs,the actual situation is that beam setting on the center of one column and the edge of the other columns ,however in etabs you can only model center to enter.(See the attached picture)
2.My first question is leading to my second question,if I model beam center to center ,I have to delete this part of slab that lies outside the beams






RE: How to model Beams in Finite element software
RE: How to model Beams in Finite element software
That being said I agree with Mike, we call those "dummy" members. They are tools to work around the limitations of a program, you have to understand how the forces are transferred and then try to mimic these loading by getting clever with the program.
That being said, your model is not a true finite element model. If it were, you wouldn't have this problem.
RE: How to model Beams in Finite element software
have a look at the results once the analysis is performed. If it isnt as expected, model the beams center to center and that part of eccentricity as an additional moment carried by the column.
RE: How to model Beams in Finite element software
Mike you hit exactly what I was thinking ,what I did I made very stiff element there to overcome the eccentricity ,hence I use this to transfer the load properly as the actual situation, but I don't read moment on it(not actual, since it is part of the column).
andriver
you are right it is not completely finite element model (I do agree)
I have a very common question that I keep thinking in my head
Suppose I have tie beams in the foundation(those tie beams above the foundations not on the same level of foundations, so do I need to model them when I study the building ,and what is the length of column I should consider? is it from top of footings to bottom of the first slab coming through slab on grade.
And this may lead to my second question what is difference between tie beams with foundation levels and tie beams above foundation levels(in terms of modeling and purpose)
RE: How to model Beams in Finite element software
RE: How to model Beams in Finite element software
If you're wondering if there will be localized issues in the beam and there isn't a good equation in the applicable code, you could build the beam elements out of plates equal to the web/flanges of the beam. For example: your beam is a W16x40 with d = 16.0, bf = 7.0, tf = 0.5 and tw = 0.3. You would have two parallel layers of 7.0" x0.5" plates (16-0.5) = 15.5" apart connected by a 15.5"x0.3" plate. This could give you an idea of weird bending near the eccentric bearing area.
RE: How to model Beams in Finite element software
RE: How to model Beams in Finite element software