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Sign Convention

In AdSec the section is considered to be in the y-z plane as illustrated below

Y-z plane diagram

This means that moments are defined as follows:

Momemt formula diagram.

The following table illustrate moment, compression and curvature conventions

Myy\mathrm{M}_{\mathrm{yy}}Mzz\mathrm{M}_{\mathrm{zz}}Moment angle, θ\thetaNeutral Axis angle, θNA\theta_{\mathrm{NA}}κyy\kappa_{y y}κzz\kappa_{z z}Diagram
+M000+ ve0Momemt diagram 1
+M+M−45∘-45^{\circ}−45∘-45^{\circ}+ve+veMomemt diagram 2
0+M−90∘-90^{\circ}−90∘-90^{\circ}0+veMomemt diagram 3
-M+M−135∘-135^{\circ}−135∘-135^{\circ}- ve+veMomemt diagram 4
-M0−180∘-180^{\circ} (180∘)\left(180^{\circ}\right)−180∘-180^{\circ}, (180∘)\left(180^{\circ}\right)- ve0Momemt diagram 5
-M-M135∘135^{\circ}135∘135^{\circ}- ve- veMomemt diagram 6
0-M90∘90^{\circ}90∘90^{\circ}0- veMomemt diagram 7
+M-M45∘45^{\circ}45∘45^{\circ}+ ve- veMomemt diagram 8

Key: C = Region of Compression M = Any particular moment NA = Neutral Axis