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# How is Section Modulus Used in Profile Bending Steel?

## Forword

Section modulus is a measure of the shape of the crosstie and is calculated by dividing the MOI by the greatest distance of the section from the neutral axis, calculated from dimensions and rectangular cross-section.

To determine if a steel section can be curved you need to first determine its section modulus and then see if you have the correct bending equipment.

Section modulus is the direct measure of the strength of the steel. Bending a steel section that has a larger section modulus than another will be stronger and harder to bend.

Section modulus is a geometric property for a given cross-section used in the design of flexural members.

There are two types of section moduli, the elastic section modulus (S) and the plastic section modulus (Z). In the case for bending a steel section it is important to calculate ‘S’ by taking the moment of inertia of the area of the cross section of a structural member – divided by the distance from the neutral axis to the furthest point of the steel section. This is where the steel will bend first.

The bending moment that it takes to yield that section equals the section modulus times the yield strength.