PT analysis and design 6

[BulbTheBuilder]

I am trying to wrap my head around PT design on two items. I am still new to prestressed design so these questions might sound basic.

1. The hyperstatic force from the PT-tendons helps in balancing the load thus reducing stresses due to moment. Resultant of the precompression force stress and the bending moment stress leading to lesser stress in the system. How come the PT doesn't "help" with punching shear? Now assuming if I balance say 100% of the self-weight of the slab I now have to deal with super-imposed dead and live load for my bending and deflection. Why can't I consider same for shear?

2. Do you consider live load reduction in a two-way flat plate and what are your views on them? I am thinking about considering live load reduction for flexural and unreduced live loads for my shear check just to be on the safer side. Let's assume I have a floor usage for computer use (100psf) and I reduced the load to 80psf, can the floor be used for the intended computer use? Can I count on the redistribution of forces, how does this play out on the field when the building has been constructed?

 

[Luceid]

Bondy posts his lectures from his past UCLA class online as well - it walks through almost identical to what the book is, but it is nice to have on hand

 

[BulbTheBuilder]

@KootK (Structural)
I did see that one later that night. But I chose to wait and ask an old fella (mid-70s) today and guess what? He's retiring this September, so he is willing to give it me for free. He has the third edition (cyan cover). I feel so lucky

@Luceid (Structural)
Dirk Bondy? Great ! I have seen it! Thanks a lot! He has a recent upload (Lecture 1 - Introduction to Post-Tensioned Concrete (2023 but recorded 2022) I think that would be a great start for me.

 

[BulbTheBuilder]

And it is here! Got it before September,

 

[KootK]

Nice. I jealous. I had to accept a 2nd edition in order to get a hardcover at a reasonable price.

 

[KootK]

And it is here! Got it before September,

This begs the obvious question: can I have your copy when you die?

 

[BulbTheBuilder]

My statement was "It will be a shame for such a good book to go waste in a basement"

But I have gotten some really good books (design of welded structures, Theory of elasticity, foundation analysis) from people retiring. I have discovered a new hack in getting some great books. Thinking about hanging up the gloves, KootK?

 

[Luceid]

I second the above, would be happy to snag any unwanteds from the crowd