I am shifting from the British standard BS8110 and the European EC2 to the American standards ACI, your videos have been very helpful, I would like to express my gratitude for your efforts.

@StructuresProfH

10 ай бұрын

Thank you! I'm glad you've found these useful.

This video should be shown to every prospective engineering student, guarentee people will go a different route.

This is one of the best video for RC shear presented by one of the best structural engineering professors!

@StructuresProfH

Жыл бұрын

Thanks, Han!

@aboudeh21

Жыл бұрын

yeah exactly

The way you explain difficult topics easily is remarkable. Thank you very much for your time.

@StructuresProfH

Жыл бұрын

You are most welcome!

grate & sufficient explanation how to be economical & safe design metedology ❤

very good and clear. i hope to use si units code in separate lectures series that will make it easier for some people like me work outside usa.

great video, thanks for sharing.

Thanks for the explanation

Well done bro

Wow!! thank you bro

If considering SDC D E F was required ,in this situation how to calculate Vu for demand

Great video but what is this number 0.0156 that you don't define?

@StructuresProfH

Жыл бұрын

That’s the value of rho_w (the reinforcement ratio) where the two V_c equations are equal. For rho_w less than 0.0156, the 2*root(fc’) equation will be greater, and for rho_w greater than 0.0156, the second equation will be greater. This isn’t in the code, and it’s not necessary to know, but it is nice to keep in mind if you are trying to maximize V_c.

@michaeladams2878

Жыл бұрын

@@StructuresProfH Thanks, that was very informative video!

I looked into the ACI code but still don't understand what Nu is, and why in this problem equals to 0 🤔. Could anyone explain that?

@StructuresProfH

Жыл бұрын

Nu is the axial force in the beam when subjected to the factored shear Vu. For the example in this video, the beam has no axial force, meaning Nu = 0. It's rather odd that ACI 318-19 uses two different symbols for axial load. Normally, Pu is the factored axial load, but for some select shear and torsion equations, the code uses Nu. It's a subtle distinction. Definitions for these are in Chapter 2 of ACI 318-19 as follows: Nu = factored axial force normal to cross section occurring simultaneously with Vu or Tu Vu = factored axial force

Hello prof. Shall the size reduction factor be considered for pile cap design?

@StructuresProfH

5 ай бұрын

It's a bit confusing, but it looks to me that ACI-318-19 does require you to use the size factor for pile cap design. Section 13.2.6.2 states that the size factor can be ignored for shallow foundations (specifically, "one-way shallow foundations, two-way isolated footings, two-way combined footings, and mat foundations"). It says nothing about deep foundations, which have their own section 13.4. The pile cap section 13.4.6.3 just sends you to 22.5 for shear capacity, with no mention of ignoring the size effect factor. I'm not sure if this was intended, but it seems that's what we have. If it is any consolation, it gets even worse if you look into plain concrete. Inexplicably, plain concrete does NOT have a size effect factor, even though size effects would (per theory) be a bigger concern for plain concrete sections compared to reinforced concrete sections. Because of this, the plain concrete provisions in Section 14.5.5 can give you HIGHER strength than the provisions in 22.5 when you have lightly reinforced sections. For example, say I have d = 24", reinforcement ratio of 0.005, and no shear reinforcement. Section 22.5.5 gives me 1.05*sqrt(f'c)*bw*d for the capacity, whereas for plain concrete I would get 1.33*sqrt(f'c)*bw*h... and h > d so I get another minor benefit to plain concrete. Even accounting for the different strength reduction factors (phi = 0.75 for shear but only 0.6 for plain concrete), the plain concrete comes out on top, leading to the perverse incentive whereby I can remove reinforcement and gain strength per the code! Don't do that, by the way.

Thank you. What is the minimum spacing for stirrups ?

@StructuresProfH

5 ай бұрын

Maybe someone else in the comments can jump in - I couldn't find a code provision specifically for stirrups (weird?) even though this is clearly defined for ties, spirals, etc., in Section 25.7 of ACI 318-19. Anyway, I would maintain a minimum clear spacing of at least 1 inch, which is consistent with the provisions for ties and spirals. You need to make sure the concrete can flow and fill around the reinforcement.

@abod--lr6kx

5 ай бұрын

@@StructuresProfH Thank you professor, you are the best 👍

Thank you Professor. In step 5 you multiply Vn = Vc + Vs by phi. Why? In Eq 22 . 5 . 1 . 1 in the code, there is no phi

@StructuresProfH

10 ай бұрын

Chapter 22 in the code always gives the nominal strength. The strength reduction factor is called out in the design strength equations given in the respective member chapters. For example, Section 9.5.1.1 for beams states that phi*Vn must be greater than or equal to Vu, where the phi factors are defined in Chapter 21. Similar equations for the "Design Strength" are found in Section X.5 for other members, where X is the chapters 7 through 14. It's a bit repetitive and convoluted, but it is all there.

@ibrahimelbaz6680

10 ай бұрын

@StructuresProfH Thank you professor 🙏

Professor I hope you start a series of tutorials on Steel design with AISC. It will be much much better if you use a software side by side. Thanks in advance

@StructuresProfH

Жыл бұрын

I was thinking about doing something like that, though perhaps not for a few months at least. Do you have any software recommendations?

@civilengineeringwitharas4776

Жыл бұрын

@@StructuresProfH I would recommend to use Tekla Tedds for that purpose.

@tk-wl7xq

Жыл бұрын

@@StructuresProfH sap2000?

it will be better if u put some metric lectures too for Africans like me

Im officallly changing my major, this shit is extremely boring!!!!! Math is fun, but this is just plain cruel