Design of reinforced concrete helical staircase using Euroode2 3

[tadjou laura]

Hi

My name is Boris. A new member of the forum.

Usually in Eurocode for design of reinforced concrete theoritically we read from CHART(TABLES 177 of REYNOLDS AND STEEDMAN, 2005]. From this chart we can easily do the structural analysis or calculate the forces (vertical shear, radial horizontal shear, Axial forces, Torsion, horizontal moment, vertical moment at different angles.

Where can i find this chart please?? I Searched it on google but can't find it. please is there any document where i can get this chart from??

 

[BAretired]

Try Googling "Reynolds-Steedman-helicoidal Stair and Sawtooth - Esercizi".

 

[BAretired]

Boris...where have you gone? You can get the entire book by googling TABLES 177 of REYNOLDS AND STEEDMAN, 2005, just as you typed it in the original post. Have you found it yet?

 

[tadjou laura]

Many Thanks Sir and My apology for the for the late reply. I'm actually writing my end of year project.


I did find the article. But I wonder how we can do the designs of RC, with all those forces found from analysis.

I haven't find a textbook on RC design of this helical staircase type yet , but finaly calculated the forces with the help of Reynold's and steedmand K coefficient chart.


Is there any simplified way or method to calculate the RC design with these forces found Sir?


Thanks

Boris

 

[BAretired]

Designing an RC helical stair is not an every day job. I have not designed one in fifty three years of practice. If you are doing it as a project for school, the worst that can happen is you get a bad mark...no big deal, so do it.

If you are doing it for a client who may build it from your drawings and specifications, you don't have the experience to do it properly, so [highlight orange]avoid it.[/highlight]

 

[tadjou laura]

Thanks Sir,I haven't even found one textbooks about this helical provided or required reinforcement in the internet. that shows how tough is it.

There's another problem with fire provision using Eurocode2. I have a project with a column of effective length 4m.

But most of the books i find stipulates that eurocode restrict the effective length of the column to 3m.

Is there any way or algorithm in eurocode2 that solves this problems?? or any free online textbook you recommend?


Thanks in advance


Boris

 

[BAretired]

I don't use eurocode, so I am not familiar with its requirements, but I would be amazed if it restricts column effective length to 3m. That seems ridiculous to me, and I am sure there are many buildings in Europe with columns having effective length much greater than 3 or even 4 meters.

Is there any way or algorithm in eurocode2 that solves this problems?? or any free online textbook you recommend?

I can't answer either question.

Are you using a central column with stair treads cantilevering out? If so, it should be easier to analyze than a stair without the central column. Can you show a sketch of what you are planning? Include some dimensions.

 

[BulbTheBuilder]

It has been long since I used Eurocode, but I think there's a different approach to design fire conditions. Refer the link below

https://www.concretecentre.com/TCC/...Presentations/Lecture-9-fire-jb-16-Nov-16.pdf

 

[tadjou laura]

Hi Sir @BAretired, the structural plan are not completely finalized yet. When done, it will be an honor for me to send the plans latest end of the week.



Thanks for your answers

Boris

 

[tadjou laura]

Hi Sir @BulbTheBuilder

A huge thanks for the file, seen the answer my question.

Have another question please Sir @BuldTheBuilder.

Sometimes we create openings through beams and slabs for HVAC purposes to save the headroom of the building. In RC classroom we we're though to design these structures without openings.

are there any eurocode textbook or algorithm for these design please?.. haven't found one yet online.

Thanks

Boris

 

[BulbTheBuilder]

Try Concrete Beams with Openings Analysis and Design by M. A. Mansur, Kiang-Hwee Tan.

It is an old book that uses metric units but references ACI so you might want to understand it and use the appropriate equations from EC2

 

[BulbTheBuilder]

I want to assume this is a school project. Is it permissible to use flat slab in your design? I think you will over complicate the work if you are considering openings for HVAC, and you save building height as well. Unless this is a transfer beam, and you need the opening for HVAC.

Don't know if you're familiar with PT slabs, but you can do PT flat slab for bigger slabs if save headroom is important to you. P.S there are other variables to consider before deciding on any system. Best of luck with your project

 

[tadjou laura]

Hi Sir @BAretired

Here is the structural plan from robot structural analysis attached. Have problem with errors that bulge in the design of RC slab.

 

[tadjou laura]

Hi Sir@BulbTheBuilder

Please do you use robot structural analysis as your RC design software. I have some problem with the Rc slab design, don't know if you could help please.

 

[tadjou laura]

Especially for the raft foundations. a lot of errors are displayed

 

[BulbTheBuilder]

I don't use Robot structural analysis. Can you share what the issue so we can provide some guidance?

[EDIT]
I am currently looking at the image. How many storeys do you have? The raft looks huge for a school project. What is your soil bearing pressure? What are your column sizes and what is the building being used for?

S10(S26) - The value of the punching force is too big
It is either your raft isn't thick enough of you've a higher load (more than actual load due to typo or something)

S11(527) - Too little safety factor - reinforcement required
Is your raft unreinforced? Note that you will be both top and bottom reinforcement. Also check the factor of safety you're using. School projects, you can get away with 2.0. But if values were provided, use those.

 

[BAretired]

Hi Sir @BAretired

Here is the structural plan from robot structural analysis attached. Have problem with errors that bulge in the design of RC slab.

https://files.engineering.com/getfile.aspx?folder=cddc7af4-6823-4adf-b670-6

I cannot open this file.

 

[BAretired]

I can open this file, but I have no idea what to make of it. Does not look much like a helical stair to me.

 

[tadjou laura]

Many thanks for your answers.
I have a situation in RC beam design. Usually in a STORY level a beam is heavily loaded more than another.

In that situation, should we size a beams with variable depth so as to reduce the deflection of slabs, but difficult for formwork purposes or should should we put in more steel .

 

[tadjou laura]

The building is for office purposes.