[BOUNDARY]     How to provide support at base of a curved bridge deck?

In cases where a superstructure is modelled without substructure, the bottom nodes of the superstructure will have to depict the behavior of
bearing.



For curved bridges, the rotation and translation of bearings have to be in accordance with the curvature (tangential or perpendicular to the curve). This behavior can be simulated by defining node local axis for the support nodes which will declare the direction of translation
and rotation of bearings.

To define Node local axis
1. Boundary > Node Local Axis.
2. Local Axis could be defined in four ways.
- Angle : Angle of rotation about global X, Y and Z axis needs to be specified to rotate the axis for specified node.
This method is the simplest way of assigning node local axis.
- 3 Points
- Vectors
- Line




For details on other methods refer ‘Online help manual’
(Press F1 on working window)

Node Local Axis could be viewed only for those nodes where the axis have been changed and not at all nodes.



To view the assigned node local axis, navigate to
1. View > Display Options.
2. Under Node tab, check the Node Local Axis option.

Supports defined at nodes with node local axis will have restraints along the defined axis of the node and not the global axis directions. The reactions as well as the displacements
could be obtained along these local axis as well as global axis.