Would like to make a shout out in the auditorium- big thanks to the Prof. You are bringing good value to the space. Please keep it up. Just found out I passed my PE exam. Your content helped me out for the afternoon session. I will tell you what- I know I crushed the concrete beam shear problem that was on my test. Big ups!
First I want to thank you about this video , second what do you think the beat book to learn reinforcement concrete design according to aci i try nilson book but have a problem with example in this book not practical
Working as mostly a drafter atm, but one thing that an engineer brought up to replace rebar stirrups, is to use WWR mesh to accommodate. Seems like that would be a good way to go for some things since the diameter of the steel is much smaller, typically of higher grade, and one wouldn't have to place multiple stirrups during fabrication. Do you foresee any potential issues with that WWR/stirrup approach, or would that be a good path to reduce the amount of materials and maintain max spacing requirements? Just trying to get a sense of what you think and if there are any limitations to watch out for. Great videos btw. Really helps with figuring out what is important so I can get a PE eventually, or at least have enough knowledge to help make sure designs are safe as well as efficient.
Hi David, when Av is required per the ACI then a lot of the time Av min requirements will also be required. because of this you will be hard pressed to get WWR to meet those requirements. WWR is like welded wire fabric correct? that's what im picturing. and if that is the case WWF has very little steel area. great ideas tho. please let me know if im understanding you correctly.
@@Kestava_Engineering Yes, you were understanding correctly. Sorry for the late reply. Not sure why I didn't get notified, but yeah, I agree. As I work in the field I am finding that WWR can work if sized and spaced correctly, but mainly in places that are small, like a slab with holes in it that is in the realm of 10x10 ft horizontal dimensions and if those slabs are standard precast products used often (wwr takes more time to make than bar due to ordering and design processes). When things get bigger, it often seems that the flexibility of stirrups in rebar format would be better so adjustments can be made during cage assembly. Definitely a trial and error sort of thing. I work in a plant environment, which is nice in a way, as I get to see the impact of design decisions pretty quickly. As far as the math. WWR can replace bar. For example, if one needs #3 bar @ 4" oc, then one could probably use D-11 wire @ 4" oc assuming same grade of steel, since the area steel per bar/wire is nearly the same. Sometimes the wwr is faster to use, and therefore cheaper. I have used WWR a bit to work to improve shear capacity while also providing something like "scaffolds" for top mats to help with assembly... that definitely helped speed of production.
Great video again btw (refreshing as time is coming for testing!), more to my point with the wwr though, we could hypothetically use wwr to get a "bar" smaller than #3 as you were talking about shortly after timestamp 14:00 of this video. Situational use still, and won't always be the best choice, but I think wwr could be a good candidate to consider when we want a smaller "bar size".
you're correct - it is just Vs. however i like to compare with phi included so i can quickly compare by doubling the concrete capacity. adding phi to both sides of the equation should not change the comparison. but if you disagree you can / should use Vs for sure!
you only get to use the steel that is going through the shear plane. the top and bottom of the shear stirrups do not cross the shear plane. think about how a beam fails in shear and the look what shape the shear plane is. hopefully this helps! i can talk a little further in this