This was neat. As a layperson, it can be daunting to look at subjects like engineering. I enjoyed the instruction, and that this is in a video so I could back up to review without disturbing classmates. Concrete engineering is a pathway to many structures that some would consider... unnatural.
I suggest that you should have fewer than 5 top bars in an 18" wide section. The clear space between bars is only about 2.1" which is marginal for getting the concrete in and will not allow use of a vibrator. I try to provide 2.75" clear for top bars. The vibrator doesn't have to fit between the bottom bars so they can be spaced closer together. You mention Dr. REK- I also had him as a professor, I'm sure long before you did.
P.s Got the 7 lbs. Per yard from some load studies on fiber reinforcing sans the rebar. That number gave the best load rating for a concrete beam under a static load.
I find your videos very easy to understand, interesting and instructional and I thank you for all your help. Although I've tried numerous times, I haven't been able to model and inclined support in Risa 2D. Can you please show how to model inclined roller supports in Risa 2D?
Thanks for the message. I am not sure Risa 2D can do this. I think the boundary conditions only go in the global X, Y, Z. However you should be able to use their solution with a little math to find the inclined answer.
@@TylerLey Thank you so much for your quick response. I'll try some examples to see if I can figure it out. I enjoyed very much your live steaming today. Please keep up the good work.
I assume you men roller support because inclined pin or inclined fixed don't mean anything. You would model this with an inclined link. You want to resist force in one direction so you orient the link in this direction, with enough stiffness (A and E) that it doesn't deflect significantly. You want to allow free movement in the other direction perpendicular to the link and you don't want to resist bending so you pin both ends of the link. The force in the link will model the reaction that you would get from an inclined roller.
Hi Professor Tyler. What happens if you omit negative moment reinforcement? How can you avoid cracks without having to place negative moment reinforcement
If the bending moment causes enough tension stress in the concrete to exceed the modulus of rupture then it will crack. (And actually it will crack whether it has reinforcing or not, the difference is the width of the crack.) So to avoid cracks you have to keep the tension stress below the cracking strength of the concrete.
Just thought I'd throw a few of my thoughts in. Not a big fan of steel reinforced. Yes I know that the expansion/ contraction rate for rebar versus concrete are supposed to be compatible. But your video implies live or deadloads are basically static. Introduce the motion of an earthquake and your numbers and calculations come up short by several factors. What about this idea. Carbon fiber strands( 7 lbs. Per yard) , and an elastomeric admix for the pour.. With cf strands, elastomeric admix and cf cables laid in to replace the rebar. Wouldn't you have a superior post and beam with a much stronger slab? This would allow for better point of moment integrity. With future micro cracks there would not any rebar rusting and expansion. Just my thoughts.
Just thought I'd throw a few of my thoughts in. Not a big fan of steel reinforced. Yes I know that the expansion/ contraction rate for rebar versus concrete are supposed to be compatible. But your video implies live or deadloads are basically static. Introduce the motion of an earthquake and your numbers and calculations come up short by several factors. What about this idea. Carbon fiber strands( 7 lbs. Per yard) , and an elastomeric admix for the pour.. With cf strands, elastomeric admix and cf cables laid in to replace the rebar. Wouldn't you have a superior post and beam with a much stronger slab? This would allow for better point of moment integrity. With future micro cracks there would not any rebar rusting and expansion. Just my thoughts.
I've been designing concrete for 45 years. You teach this so we'll. I wish my teachers had been so concise and practical. Awesome.
Thank you so much for the nice words! I really appreciate it.
This was neat. As a layperson, it can be daunting to look at subjects like engineering. I enjoyed the instruction, and that this is in a video so I could back up to review without disturbing classmates.
Concrete engineering is a pathway to many structures that some would consider... unnatural.
Thanks for the comment. I am glad you liked it.
awsome training.
You are awesome mate thanks for this material
Dude you’re a better teacher than the sum total of all my engineering teachers
Thank you so much Chad! That is such a cool thing to say.
I suggest that you should have fewer than 5 top bars in an 18" wide section. The clear space between bars is only about 2.1" which is marginal for getting the concrete in and will not allow use of a vibrator. I try to provide 2.75" clear for top bars. The vibrator doesn't have to fit between the bottom bars so they can be spaced closer together.
You mention Dr. REK- I also had him as a professor, I'm sure long before you did.
you deserve more than one like, thank you very much
Well appreciated
Thank you so much!
P.s Got the 7 lbs. Per yard from some load studies on fiber reinforcing sans the rebar. That number gave the best load rating for a concrete beam under a static load.
Great sir. Please give the construction site details in lectures....
I find your videos very easy to understand, interesting and instructional and I thank you for all your help. Although I've tried numerous times, I haven't been able to model and inclined support in Risa 2D. Can you please show how to model inclined roller supports in Risa 2D?
Thanks for the message. I am not sure Risa 2D can do this. I think the boundary conditions only go in the global X, Y, Z. However you should be able to use their solution with a little math to find the inclined answer.
@@TylerLey Thank you so much for your quick response. I'll try some examples to see if I can figure it out. I enjoyed very much your live steaming today. Please keep up the good work.
I assume you men roller support because inclined pin or inclined fixed don't mean anything. You would model this with an inclined link. You want to resist force in one direction so you orient the link in this direction, with enough stiffness (A and E) that it doesn't deflect significantly. You want to allow free movement in the other direction perpendicular to the link and you don't want to resist bending so you pin both ends of the link. The force in the link will model the reaction that you would get from an inclined roller.
Hi Professor Tyler. What happens if you omit negative moment reinforcement? How can you avoid cracks without having to place negative moment reinforcement
If the bending moment causes enough tension stress in the concrete to exceed the modulus of rupture then it will crack. (And actually it will crack whether it has reinforcing or not, the difference is the width of the crack.) So to avoid cracks you have to keep the tension stress below the cracking strength of the concrete.
Please make a video on Polystyrene Concrete
I think that would be a good one. I will see what I can do.
Sure
What program did you use to find the Moments? Thank you and great video!
I typically use Risa 2D. Video here:
ruclips.net/video/1BLQPsfwpuQ/видео.html
Just thought I'd throw a few of my thoughts in. Not a big fan of steel reinforced. Yes I know that the expansion/ contraction rate for rebar versus concrete are supposed to be compatible.
But your video implies live or deadloads are basically static. Introduce the motion of an earthquake and your numbers and calculations come up short by several factors.
What about this idea. Carbon fiber strands( 7 lbs. Per yard) , and an elastomeric admix for the pour..
With cf strands, elastomeric admix and cf cables laid in to replace the rebar. Wouldn't you have a superior post and beam with a much stronger slab?
This would allow for better point of moment integrity. With future micro cracks there would not any rebar rusting and expansion.
Just my thoughts.
I saw the 70 videos you made about concrete. But this is to difficult to follow.
Just thought I'd throw a few of my thoughts in. Not a big fan of steel reinforced. Yes I know that the expansion/ contraction rate for rebar versus concrete are supposed to be compatible.
But your video implies live or deadloads are basically static. Introduce the motion of an earthquake and your numbers and calculations come up short by several factors.
What about this idea. Carbon fiber strands( 7 lbs. Per yard) , and an elastomeric admix for the pour..
With cf strands, elastomeric admix and cf cables laid in to replace the rebar. Wouldn't you have a superior post and beam with a much stronger slab?
This would allow for better point of moment integrity. With future micro cracks there would not any rebar rusting and expansion.
Just my thoughts.