1. Introduction, Course Breakdown

Reinforced Concrete Design to EC2
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Questions and discussion for this lecture live here. Fire away by hitting Reply below :fire:

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Hi Sean,
I am a member but I can’t lunch vidéos of this course.

5

Hi Abdelhaq,

Yes as the course is still under construction (very nearly finished!), this lecture doesn’t actually have a video yet. The first video is on lecture 4.

Seán

[Edit → Video is now live…as you can see above :slight_smile: ]

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6

Hello,
First of all, thank you very much for everything you have done. I love improving my Python skills and my knowledge of structural analysis. Thank you.

I just realized that the course on the old site labs.degreetutors.com was “readable,” meaning there was a lot of very interesting text below the video. Will you be adding this text later? Because after watching your video, I like to read it.
Thank you.
(Sorry for my Franglish).

Pierre

7

Hey Pierre,
Yes absolutely - I’m literally in the middle of migrating the text lessons for this course over from my Labs site. By the end of the month (and hopefully a little sooner) I should have all text lessons for this course ported over.

Great to hear you’re enjoying the course!

Cheers,
Seán

8

Hi Sean,

This looks like an interesting course. Currently, I’m exploring a few specific questions, and I’m curious if this course covers the theory to calculate:

  1. The effective moment of inertia for steel-fiber reinforced concrete (to calculate deflection).
  2. T-section analysis when flanges are in tension (to calculate stresses in slab reinforcement and justify effective flange width for section analysis).

I also join other comments and want to thank you for all your work and efforts in sharing knowledge and building the community. It’s really inspiriting :slightly_smiling_face:

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Hey @ilya,

We don’t cover moment of inertia calculation for fibre-reinforced concrete - that’s an interesting idea…I would have assumed it would be the same as a regular section - it’s not immediately obvious what influence the fibre reinforcement has on the I value - am I missing something??

We do look at the design of T-sections but not when the flange is in tension. I’m working remotely at the minute so don’t have access to my design guides and references so I can’t say what the EC2 guidance on this is. l guess that you’ve already considered the easy option of assuming a flange width equal to the beam width and this isn’t sufficient?

S

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Hi Sean,

Thank you for the reply. I think I did not formulate the question correctly.

The moment of inertia of a gross section would, of course, be the same, but I wonder if steel fibre in concrete would increase cracking moment (by increasing modulus of rupture), or maybe it would affect the modulus of elasticity, which would affect distance to the neutral axis and, consequently, the moment of inertia of the cracked section. So, the problem comes down to figuring out how steel fibre affects concrete cracking which should result in the reduced deflection.

Regarding the T-section, the problem is that I am using a narrow beam (100mm wide rib in a waffle slab) and there is not much room for steel if we don’t use flanges.
I am using the New Zealand Code (which is largely aligned with the EC). It allows the use of reinforcement in the flanges only if the “total contribution of flexural tension force in each outstanding portion of a flange does not exceed 10% of the total flexural tension force,” which means that I can only consider reinforcement within the web and a little bit of steel in the flanges. There is a clause that says it is possible to use more longitudinal reinforcement from the flanges provided that a strut and tie analysis demonstrates that the shear flow in the flanges with longitudinal reinforcement is adequately connected to the beam web by transverse reinforcement. So the question is how to do the strut and tie analysis right :slight_smile:

I am not sure that this forum is meant for this type of questions, but I would be grateful for any comments. :slight_smile:

Thanks,
IM

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Ah - yes I see what you mean re. steel fibres and the likely increased crack resistance. I must say that I haven’t worked with steel fibre reinforced concrete and wouldn’t be in a good position to advise you here - I have often wondered how one performs the section analysis on this type of section though! I would greatly appreciate your feedback, once you do work it out :wink:.

In terms of the strut and tie analysis - we do actually consider this in the course (lectures 30 and 31) when we consider longitudinal shear resistance. This should give you some insight into how to apply the variable strut model to your specific case.

You can ask any engineering question you like :slight_smile:

Seán

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