Bending Moments
While it is not necessary to view bending moments, it can be useful, especially for irregular structures. Even though principal moments are important, the default moment contours plans are for Mx (moment about the x-axis) and My. This is because most designers detail reinforcement orthogonally, and the directions are usually the x- and y-axes. You can view moments about any axes, including the principal axes.
It is not particularly easy to assess the moment contours. This is why Plot Distribution Tools are so useful.
View Moments
-
Choose Layers > Load Combinations > Code Specific Load Combination > Mx Plan.
For ACI318, use Factored LC: 1.4D.
For AS3600, use Ultimate LC: 1.2D + 1.5 L.
For BS8110, use Ultimate LC: 1.4D + 1.6L + 1.6S.
For IS 456, use Ultimate LC: 1.5D + 1.5 L + 1.6S.
For EC2, use Ultimate LC: 1.25D + 0.9H + 1.5L + 0.75S
For CSA A23.3, use Factored LC: 1.4D.
The contours are moment per unit length about the global x-axis.
-
Turn on Snap Orthogonal (
)
-
Click the Selected Plot Distribution tool (
).
- Click first at the top of the structure and again on the bottom side. This shows the bending moment shape, about the x-axis, along the line you have drawn. See the following figures.
- Now click from left to right across the structure.
