08/11/2023
Can you interpret a shear force diagram of a beam and just by looking at it, deduce with some accuracy what is happening in practice?
I always tell my students: Just as a doctor has to know how to look at a serological test, an X-ray or a CT scan, we engineers have to know how to analyze the force diagrams of a structure and the borehole reports of a soil!
So let's learn together how to analyze these diagrams?
SHEAR FORCE DIAGRAM
The shear force diagram is the representation of the forces that cause transverse shear.
In reinforced concrete structures, it is used to design stirrups.
And like any diagram, it can appear in various forms: constant, linear and parabolic sections.
When you have a constant section in a shear force diagram, this means that there is no load on the beam in that segment!
It's worth remembering that this situation is merely theoretical, since it's impossible for a structure not to have at least its own weight acting.
And if you see a linear section going down, this means that on the beam we will have a uniformly distributed load, which could be a wall or a slab, for example.
Now, if you have a parabolic section, it means that you will have something like a triangular wall, very common in roof enclosures.
What about when the graph jumps from one place to another?
Mathematically, this is a discontinuity in the function and in practice, it indicates that something concentrated is there.
This could be either a pillar reacting upwards (+) or downwards (-) or even a transition pillar acting on our beam!
Cool, right? After this post, it's impossible not to know how to look at an "examination" of a structure, isn't it? → Via:
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👷♂️
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