I wanted to understand how these softwares are different in terms of the complexity of analyses and accuracy of results. I'm looking at performing Time History Analyses over a set of ground motion data and have observed slight differences in the results obtained using the mentioned software. I wish to know the reason behind this and why do we not hear about Drain 2Dx as often as SAP2000 or ETABS.
Dear Rohit,
I believe that the results of these two softwares should not be so different because these two softwares are basically similar. However, Sap is more complex and Etabs is more spedific and easier to use for small construction buildings with normal materials like concrete or steel.
Hope this helps
Hi Seyedsaleh Mousavinezhad sir. Thanks for your answer. Regarding SAP and ETABS, I understand that they are virtually the same software with some differences. However, I do not see any specific mention of the utility of Drain-2DX in your answer. It would be fantastic if you could provide some insight into it. My results from SAP and ETABS are nearly similar, with some minor differences that I suppose can be neglected.
Drain-2DX is an older software still used for research purposes but it is not a commercial software like the ones from CSI (SAP2000, ETABS, BRIDGE, SAFE, etc). Unlike Drain you do not need to know what you are doing to operate the software since is very user friendly thus it a popular tool for structural analysis and design.
As for the results CSI software allows you to choose:
- The type of solution: modal analysis, direct integration or frequency domain
- The number and size of output steps
- The damping options that change with the type of solution selected
All these options change the output, also, the refinement of the model (size and type of meshing) has an important effect particularly in complex models.
It is my experience that you can achieve very similar results in commercial programs to most engineering applications in much less time than in software used for academic purposes like Drain, Canny, Raumoko, etc.
See chapter XXI of the CSI reference manual for a detailed explanation on the above.
I also attach a user manual of Drain that's quite old but is the one I was given in my masters.
Hope it helps best regards!
Thanks a lot David Flores Vidriales sir for your answer. One more thing that popped up in my mind from your answer is that CSI products do allow us to choose whether or not we wish to perform a Modal or Direct Integration time history analysis, which one of them is used by Drain-2DX in the background? In simpler terms, does Drain-2DX perform a Modal Time History analysis or is it Direct Integration?
I'm not quite sure, but a wild guess would be the Direct Integration since Drain takes much longer to produce results (at least in my experience) . Unless you are using a refined model the modal is a good enough approximation.
You can try to run all available options on SAP and see which ones approximates better to the Drain output, if you do, let me know it seems interesting.
Best regards
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