Bearing Fixity
This section defines the translational and rotational fixities at each bearing location, controlling how forces transfer between the superstructure and substructure.
Steps
Step 1: Navigate to Bearing Fixity
Navigate to Superstructure > Boundary Conditions > Bearing Fixity in the tree view.
Step 2: Select Insertion Points
Click the first cell in the Insertion Point column, then click Pick to graphically select the insertion points that define boundary conditions.
Step 3: Define Fixities
For each bearing location, set the fixities or stiffness values in the Tx, Ty, Tz, Rx, Ry, and Rz directions based on the bearing type.
Step 4: Set Transfer Force to Substructure
Set Transfer Force to Substructure to Yes for all bearing locations where substructure is modeled.
Yes: Creates a two-node spring between the pier cap and girder (use when substructure is modeled)
No: Creates a one-node spring at the bottom of the girder (use for abutment locations without modeled substructure)
Quick Tip: Degree of Freedom Reference
Nodes are assigned degrees of freedom (DOFs) based on the local coordinate system at each insertion point, which varies along the support line and alignment.
Tx/Ty/Tz/Rx/Ry/Rz fixities:
Bearing Rotation rotates the support clockwise in the XY plane:
Transfer Force to Substructure FE behavior:
Verification
After completing these steps, your bearing fixity configuration should match the view shown below.
Video Walkthrough
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