# Beam section and shear stress.

1)When we are asked to calculate the shear stress at AB should we consider the width as T or as 2T?

2)And when applying t=vq/it what sections should we take and is the value we found located on the bottom of the area?(I'm not talking about this beam but any beam in general)

3)And finally given V how can we found the location of the maximum stress?

Thank you. The first question is the most important for me.

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PhanthomJay
Homework Helper
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1)When we are asked to calculate the shear stress at AB should we consider the width as T or as 2T?
I guess we need your thoughts on this first as to what you think should be the value to use, T or 2T. Does the 2nd leg serve any purpose in strengthening the section in bending and shear?
2)And when applying t=vq/it what sections should we take and is the value we found located on the bottom of the area?(I'm not talking about this beam but any beam in general)
the area to be used in determining Q depends on the location in the cross section where you want to determine the shear stress. So in determining Q, you could use the area above or below that location to find the shear stress at that location.
3)And finally given V how can we found the location of the maximum stress?
Q is max at the _____?____ of the cross section, but might there be a case, in general, where the shear stress is max elsewhere?
Thank you. The first question is the most important for me.
Back to the first question, is it T or 2T? Supposing you just wanted an average shear stress in the vertical legs instead of the max shear stress, would you ust the area of one leg or both in your V/A calc?

Last edited:
I think you misunderstood a part in my second question. Let's say we took an area and applied the formula and we got the value of the stress. Let's say the value equals 10MPa, and if we want to draw the stress distribution of this area, where will be the 10MPa located?The bottom of the section?The top?The center?
As for the question 3, generally talking the maximum stress is at the neutral axis, but if we're asked to determine the maximum stress given a certain V should we just go for the calculation on the N.A?
Thank you, I hope you reply again.

PhanthomJay