Prestressing, Post-Tensioning, Pre-Tensioning

Thank you Sir! Finally someone explained these in a simple way.

simple, neat and clear

Great vid 👍🏼

THANK YOU VERY MUCH!!!

I believe the image at 2:55 is the walkway between both sides of the Orange line at the Bonaventure Station of the Métro de Montréal. I suspect that post tensioning was used for all stations of the Métro de Montréal, as per the Place Ville Marie project a few years before (Place Ville Marie is build almost on top of the Bonaventure Station). An example of concrete pretensioning is the Stade olympique de Montréal (Montréal Olympic Stadium). Most of the large parts were precast.

Kronk, is that you?! Just kidding. Great video!

Cool dude , cool

These videos are super awesome! I have so many questions. Who are you? How do you know all this stuff? Do you teach at Virginia tech? What do u teach? Have u written any books? How van I learn more about you. And more importantly please keep putting these videos out they are amazing!

This is amazing .. why does it end all of a sudden is this like an online curse ?

super explanation clearly understandable

Why are comments disabled for the "How electricity works. . . . animated" video? And first and foremost why is the video cut...?

3:39 , how do you know that tensioning will create only hogging shape, not the sagging shape?

I wonder which one is more expensive overall for some project - pre-tensioned concrete or post-tensioned... Even though I can imagine transportation of pre-tensioned concrete to be an issue, the amount of on-site work required for post-tensioning looks pretty big

You disabled comments in your "How electricity works. . . . animated" video so I am providing them here. At 7:18 you said the positive end has more electrons: not true. The negative end is the current source and the positive end is the current void - there are fewer electrons. The electrons at the negative end are greatly attracted to the positive end which effectively contains electron holes. The electrons move towards the holes to achieve neutrality. The greater the attraction, the greater the voltage. The greater the flow rate, the greater the current. This is electron current. Engineering describes this action but in reverse: the holes move towards the electrons which is what they call hole current. Do they really? Of course, not. But it does allow them to use positive numbers in calculations which simplifies formulae substantially. Today, we call hole current, conventional current. So... to review: the negative end contains more electrons than the positive end. Please consider adding a text block to correct the misinformation. Reference: Basic Electronics, 4th Edition, by Grob. ISBN: 0-07-024923-7. Thank you.

Stop making me hit pause. Just do your video!