Modeling Moment and Shear Connections

In summary, the conversation is about a person trying to model a structure with moment connections between some beams and columns and shear connections between the remaining beam and columns in 3D using S-Frame 11 software. However, when running the analysis, an error is encountered regarding illegal constraints to the support. The person is seeking guidance on how to properly define a moment connection and clarifies that a moment connection prevents rotation and translation about all axis. The person also provides a figure and explains the general model of the steel frame building. They mention that to model a moment connection, the joint is defined as a rigid joint and the degrees of freedom are not adjusted unless it is fixed in real conditions. They also clarify that a moment connection implies that the
  • #1
CivilSigma
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Homework Statement


I am trying to model a structure that has moment connections between some beams and columns, and shear connections between the remaining beam and columns in 3D.

The software I am using (S-Frame 11) gives me an error when running the analysis for the nodes that I have defined as moment connections :
  • No rotation about x,y,z axis
  • No translation about x,y,z axis
The error is : "Illeagel constraint to the support"

Homework Equations


I know that a moment connection prevents rotation and translation about all axis

The Attempt at a Solution



Can some one please provide guidance to how I can define a moment connection or if my understanding of a moment connection is correct?

This figure represents the definition I used for a Moment connection at one of the nodes:
upload_2018-3-21_12-35-7.png


This is my general model of the steel frame building I am going to analyze under gravity and lateral loads. If you can see, I have some nodes as fixed (line with dash underneath - those are the moment connections).

upload_2018-3-21_12-30-37.png
 

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  • #2
For those who are interested: to model a moment connection, you simply define the joint as a rigid joint.

You do not play around with the degrees of freedom at the joint (only if it is fixed in real conditions, like at the foundation/base). But a moment connection implies that the members are welded together = a rigid joint (that is still able to translate about x,y,z). Also a rigid connection is the default condition set when you model a member connecting into a joint!
 

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