Questions and discussion for this lecture live here. Fire away by hitting Reply below 
Hi Sean
I’m having trouble understanding what you mean by ‘4H10 links per plane.’ Could you please provide me with a visual example or a real-life illustration to help me better comprehend this concept? I would greatly appreciate it.
This just means that if we were to take a cross-section through the beam at a plane where we have provided shear links, there would be 4 vertical shear link bars. So, in lesson 28 at about 28:04, when I show the image of the cross-section, you can see the 4 vertical bars (these are the shear links) in that section or plane.
So, if we increased the spacing between planes, we would need to provide more vertical bars per plane. Conversely, if we reduced the spacing between planes we could provide less vertical shear reinforcement per plane.
S
in 10:30 isnt the Maximum zbal = 0,82d ?
0.82d would be the minimum value of z - i.e. the the value of Z for a balanced section design. In this scenario, the concrete compression block would be at it’s max capacity.
So, values of z larger than 0.82d (up to 0.95d actually) are OK, since these would correspond with the concrete compression block being smaller.
Let me know if that’s not clear.
Seán