3D concrete design software

[pwht1]

Hey,

Could anyone please recommend and provide a review for a decent concrete analysis package that allows detailing of PT, reo and is compliant with AS3600?

Thanks,
Paul

 

[rowingengineer]

Rapt,but it isn't 3D.

An expert is a man who has made all the mistakes which can be made in a very narrow field

 

[pwht1]

Thanks, I already use RAPT but I want something that can handle complicated 2 way actions a bit better.

 

[handex]

have a look at SAFE by CSI.
Many people also use ram concept. I dont know much about it but inducta are an australian based company that have two seperate concrete packages for RC and PT, SLABS and PT3D.

 

[pwht1]

Thanks handex,

I just ordered a demo of SAFE shall give it a whirl and see.

I've been using Inducta products (slabs and RC building) for sometime now. They model the behaviour of a structure well but I'm not a big fan of the general setup nor is it very good at reo detailing or coping with things like varying the height of columns or sloping decks.

 

[rowingengineer]

I prefer to use a general FEA program with rapt as the main engine, the post processors are where the FEA programs become a black box.

An expert is a man who has made all the mistakes which can be made in a very narrow field

 

[rapt]

pwht1,

One thing you have to watch with American FEM PT design software is that they use some simplifications used with unbonded PT design in USA. These methods are not logical and are not accepted in Australia. You will have to make sure that you force the software to use logical Australian practice.

RAM Concept is the most common currently, but you have to work very hard to get reasonable deflection results. Thye have several levels of deflection calculations. Do not accept the default.

Also, by default, they ignore Mxy moments in design. This is gross underdesign and you must switch on the inclusion of Mxy in design manually!

Also, frequent users report ulrealsitically high torsional efefcts from it. Some expert users reduce their torsional stiffness to 30%. I assume this problem is common to all FEM applications for PT slabs.

Safe have only recently included PT. I do not know how good it is or how realistic it is. I do not even know if they have anyone who knows anything about PT analysis and design involved. I know that someone has recently checked their long term deflections for RC slabs (comparing to that simplictic RAPT implementation) and have found serious problems with the Safe deflection calculations that they have finally admitted to! I do not expect that it is fixed yet.

Or you can analyse on a general REM program to egt an idea of load pather etc and design on RAPT.

 

[pwht1]

Sooo you guys are telling me that no FEA programs out there are as reliable or efficient as RAPT?

 

[rscassar]

RAPT is the best program for concrete design.

 

[handex]

Rapt,

are you talking about the old version of safe having the deflection problems (version 8 only had the kcs factor method)? The new version apparently takes into account cracking and uses moment-curvature to account for shrinkage and creep? I have not used it, but looked over their verification manual and it gave values close to that of the test specimen they tested it against (for long term).

Personally I would never trust a FEM program as a black box solution for DESIGN purposes though

 

[dcarr82775]

I agree SAFE does not calculate deflections correctly. Near as I can tell it does one iteration for cracked concrete which isn't enough for a 2 way slab IMO

 

[handex]

dcarr

I am downloading the demo now to check but I saw a presentation of safe where it iterated something like 7 times for cracking.

 

[pwht1]

So what is it with FEAs that makes them so unreliable for detailed design? Is it just poor programming/engineering?

 

[rapt]

Handex,

I understand it is the new version attempting proper deflection calculations.

It was in the long term effects that thye had problems as far as I know.

 

[rowingengineer]

“So what is it with FEAs that makes them so unreliable for detailed design? Is it just poor programming/engineering?”

One of the big problems with FEA is that computer engineers have developed the products without an experienced engineer. Thus they generally apply the code directly without thought as to implication or justification.

There is also the problem that a lot of codes are written/based on non-FEM analysis. A lot of what is use in these non-FEM analyses to get a workable result is not used in FEM.

Then there is the engineers using these products, because of the complexity and time need to learn these products often the product was given to an inexperienced engineer. This was done because the younger engineer had better computer skills. However this lead to a very difficult situation. A lot of the programs have managed to go unreviewed by experienced designers until a problem occurred. It is impossible for a senior engineer to review a complex model created by another engineer without basically rebuilding the model.

In saying that there is a few good books out there that anyone attempting FEM analysis should read; Finite element design of concrete structures By Guenter Axel Rombach.


An expert is a man who has made all the mistakes which can be made in a very narrow field