Algorithm For Steel bar in Concrete

[CivilTanju]

Hi,

I need an algorithm which is capable to calculate the Steel bars in a given concrete cross-section where moment, shear-force, normal force and cross-section properties is known.

Can you direct me to sites or source - code in any language will be appreciated much more .


Tanju OZGUR

 

[Ussuri]

Sounds to me like you are trying to design a reinforced concrete cross section. There are lots of design codes out there dependent on the country you are working in.

In the UK the current standard is BS 8110 Structural use of concrete. The eurocode is BS EN 1992. There are numerous others. There are also a large number of textbooks on the subject. You could try Reinforced and Prestressed Concrete by Kong and Evans or the Reinforced Concrete Designers Handbook by Reynolds and Steedman.

 

[CivilTanju]

No, actually I'm trying to develop structural analyses program with CAD - like interface, I have almost completed it. For the given loading combination program can calculate the result foces on each elements (moment, shear-force, normal force), as I'm planning to use it in reinforced-concrete buildings, I have to implement the next step which will give the end users how many steel bar need to be used at each element. That is, searching for the best algorithm which will give me quantity of steel bar with minimum iteration.

Kind REgards,

 

[henri2]

This is way outside my league but when developing reinforced concrete CADD software, don't the steps/procedures have to take into account applicable code provisions and design methodologies?

BTW, when you refer to normal force, is this to be construed to mean axial force?

 

[CivilTanju]

You are right henri2, and I didn't say that I'll ignore these steps/procedures. To addopt them to the local code/regulation won't be a hard task to be performed ( in my idea) as a result most of European contries uses the LRFD approach just coefficients are changing. What I was trying to benefit from forum is just good entry-point where I'll start my search.


Normal force = axial force

 

[Ussuri]

Well that's me out. I know nothing about computer programming so you are well ahead of me. But when you say algorithm do you mean a formula to calculate the required amount of reinforcement (steel bars) when you know the moment, shear and axial loads? If so all the codes contain these formulae so I dont see what else you need. But like I said I am no computer programmer.

As a side note most European countries use ultimate limit state design, which is slightly different to LRFD. In LRFD you apply you load factors to the loading only. In ULS design there are partial factor of safety applied to the load and partial factors of safety applied to the materials (to take variation into account).

To confuse the issue even more, the codes in each country are all different. This is the reason the Eurocodes have been developed, to attempt to standardise the design across Europe.

 

[henri2]

Ussuri for reinforced concrete design in the US, I am sure the strength design approach also utilizes strength reduction factors (what you refer to as partial factors of safety for material strength). Perhaps what you have in mind is ASD/WSD (allowable stress design or working stress design) which is referred to in the UK as Permissible Stress Design CP 114.

 

[CivilTanju]

Hi Ussuri,
alorithms are more than formula, as we know the computers understands only one and one language(programming language)translated by their interpreter. I'm supposed to write (algorithms) to clarify everything to the computer by programming language, it includes the formulas as well as syntax which I need to pay attention.

Probably this issue is more related with sofware thread rather than structural/civil eng. thread. But I thought that the some of eng. may have interest with it and they'd like to share it with others.

Thank you
Kind Regards,

 

[Ussuri]

Henri2,

Fair cop, I stand corrected, I was under the impression it was just the load that was factored. I should maybe research my facts a bit.

 

[dik]

You likely have to develop curves, with various percentages of reinforcing, for flexure and compression and determine the balanced condition. Look in almost any concrete textbook for the development of interaction diagrams for P and M. Simple hand calcs used to determine moment capacity with a line to M balanced M and P and then to max P with a cut off at 70%. I used to have an ancient white binder from ACI that had development of these curves. I'll see if I can dig up the old binder. The P and M refer to calculated axial load and moment.

Dik

 

[CivilTanju]

Hi,
sounds like a good idea, I think doing it that way will suit best for computers, but to be honest I haven't been much into that curve developing. Anyway, at least good start point.

Thanks,

 

[oldrunner]

I think that if you do some research, you may find that all your goals for your computer program have already been done. Possibly as long as 30 years ago.

I know of some programs in Basic which addressed this as well as some intereting routines that were developed on a Wang 600 and definitely on the HP and TI programable hand calculators.

Check the ACI and the ASCE archieves.