Software
Software
(OP)
I am looking for some software that will design steel members as well as reiforced concrete walls and slabs. A lot of member design is repetitive, so I am looking for a software package that can design the individual members once I run the analysis in STAAD Pro.
Thanks
Thanks






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I think we need to change the language of the thread. Software programs do not *design* members. They're sophisticated calculators with great potential for showing good-looking results that are wrong, and they have no judgment, so should be used as such.
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Just accepting what it tells you is dangerous.
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I trusted a program once after checking some cases against hand calcs. Turned out, the program didn't check some section of the code that rarely governed. I didn't pick up the error in my comparisons, and neither did anyone else using the software, apparently. The structure needed to be reinforced. We paid. The software vendor, who admitted the error, was liable for the cost of the software, a tiny fraction of the cost of repair. Many software vendors include verbiage in the contract that limits their liability in this way.
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Without being too specific about the error which occurred, can you share with us how it was discovered, and if possible what the error was? We all learn by errors, and they should be reported insofar as possible.
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The problem had to do with web buckling of a continuous composite stringer.
Since then, the DOT has challenged the strength of a second bridge we designed using another software package. In that instance, a hand calc showed that the DOT's software was incorrect. This was the same software that the DOT used to rate the first bridge. After much discussion between the three parties, the writer of that software agreed in writing that the software couldn't be used for our bridge.
My point is that there are a lot of people selling software that is incorrect. They cover themselves by including verbiage in the license contract that limits their liability to the price of the software, a pittance compared to the cost of repair. We're fooling ourselves if we think we can verify these packages by comparing them to a few hand calcs.
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Thanks for that. So instead of checking software by hand calculation, perhaps these packages should always be subjected to checking by comparison with the results from other software. If both have errors, hopefully they will be different errors, as in your case.
We made errors in the pre-computer age as well, but I think we had a better idea of what the answers should be before we started. In today's world, we attempt so many complex structures which defy hand calculation that we have to find ways of making these programs reliable.
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Very interesting and disturbing.
Hand calculations checks can only be done in simple cases and then it would not be viable to use computer analysis in any case. But for my last design a portal frame of span 25m I actually did an analysis and design by using the old allowable stress design just as a check and actually got the same section sizes as LSD. Wind loads are not uniform across the entire rafter section so it would be extremely hard to check by hand.
As hokie66 says maybe having another analysis program on hand as a check particularly if dealing with a completely new design where sizes are not easily assessed at the start.
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I think the bottom line is still to do the manual calcs (gotta be thorough and make sure that all the limit states are verified) and know what a reasonable end result should look like. It's definitely still possible to get slammed like you guys did, but this seems to work pretty well.
Does anybody have a better idea than this? Design tables, scientific calculators, manual calcs, spec. equations, etc. have been known to have errors, so I don't see why programs would be any different.
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The AISC 13th Ed. Commentary gives some benchmark problems to test the program against. The upcoming Stability Design Guide will have more, and a slew of examples.
More fundamentally, the B1, B2 approach given in the AISC Spec. Ch. C computes amplifications that are amazingly close to what one gets from a correctly done second order analysis using a program.
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Thank you for sharing that. I suspect that few engineers take the time to properly verify the software we use.
hokie66-
I agree that, for the reasons you mention, we need to make the programs reliable. The only way to do that is to make the software vendor liable for program error. If it can be proven that a design error with the software causes a structural issue, then the vendor should be held liable. The only way I see this happening is if engineers refuse to purchase software with a limited liability clause.
281828-
I agree that "the bottom line is still to do the manual calcs." Using one software package to check another doesn't do it for me. I just don't take on anymore work that I can't do or check by hand.
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I agree with this. Comparing to another program can be a great part of the checking process, though, because of the sheer number of problems that can be compared very quickly.
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The first major portal frame job I did I used the code design package with the program. I ended up with reams and reams of paperwork that was very complicated to check.
After more experience I realised that it was usually quicker and easier to do these same calculations by hand/independent spreadsheet. You can make some very easy simplification judgements that a computer cannot and drastically cut down on the load cases to be checked for each member/connection. The more you do the hand calculations the quicker you are and also the better the feel you have for it.
It is also much simpler for someone to review your calculations.
There are many ways to check that a design is at the very worst 'not far off'. these include:
1. comparison to similar designs - works well when you are doing a lot of similar designs e.g. we had a database of over 100 jobs giving span and windspeed so that you could find one with similar criteria.
2. The critical eye of an experienced engineer can often do this job just as succesfully.
3. Comparison to simple first order hand calculations.
But the first thing you should always do after an alnalysis is to check your reactions. Apply the loads to the structure as if it was a rigid body and check that these calculated reaction are the same(or very similar) to the computer output. This at least check that you have not misaplied loads.
Next check that the total shears and total static span moment are equal or greater to that for an equivalent simply supported beam.
If you can use method of sections at critical point to check the axial and bending in members.
You should NEVER use a computer program without understanding what the results should be. The more complicated the task the more this is true.
Hope this helps.
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I like your approach and in fact use it myself. Verify by hand anything simple such as reactions on structures etc. If these check then your confidance of course increases dramatically.
One favourite (when learning how to use a new program) of mine is to use a complex truss we did at University which in fact is a critical form structures and see how the program handles it. Some programs handle it better than others and in fact this was my basis in choosing which one to purchase outright from the various demo models I had.
I guess, nothing is perfect,and we should accept this with structural analysis software.