Hogging and Sagging Moments

Hogging and Sagging Moments: Definition

In this article, we will discuss hogging and sagging moments.

Shear forces can be subjected in two directions: Upward and Downward
Axial forces can be subjected to compressive force or tensile force.

 

There are two types of moments.

One is a sagging moment and the other is a hogging moment.

The moment may be defined as the product of the force (F) and the moment arm (d). The moment arm or lever arm is the perpendicular span between the line of action of the force and the center of moments.

Moment = Force x Distance

or,

M = (Fxd)

The Center of Moments may be the real point about which the force causes rotation.

 


 

Hogging and Sagging moments are the types of moments working on the structures.

 

  i. Sagging Moment  

The moment that pushes the beam concave upward is called the sagging moment. It is commonly considered a positive moment.

At this moment, the upward beam compresses, and the downward the beam expands. So, stresses are produced called bending stress.

 

Hogging and Sagging Moments

 


 

  ii. Hogging Moment  

The moment that pushes the beam concave downward is called the hogging moment. It is considered a negative moment. The upward point is under tension and the below point is under tension.

There is a line along an axial direction that is under neither compression nor tension. It is called the neutral axis.

The points beneath the neutral axis are under tension in the sagging moment and under compression in the hogging moment and the manner around in the next case.

 


 

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