Module 9: Combined Stresses - Theory & Concepts - Middle Third Rule

Combined axial and flexural loads and eccentrically loaded members.

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Middle-Third Rule Simulation

Load Eccentricity (e)

Status

All Compression

Base Width ( $b$ ) = 120 units
Kern Limit ( $b/6$ ) = $\pm$ 20 units

When the load $P$ is applied within the green highlighted Kern (the middle third of the base), the entire cross-section remains in compression (blue distribution).

If the eccentricity $e$ exceeds $b/6$ , the bending stress ( $Mc/I$ ) becomes greater than the uniform axial stress ( $P/A$ ) on the opposite face, causing tension to develop (red distribution).

Module 1: Simple Stresses - Examples & Applications Module 2: Simple Strain and Deformation - Theory & Concepts - Stress Strain States Module 2: Simple Strain and Deformation - Theory & Concepts - Strain Deformation Module 6: Stresses in Beams - Theory & Concepts - Stresses Beams

Middle-Third Rule Simulation

Status

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