Blast analysis using Direct analysis method

RE: Blast analysis using Direct analysis method

NIKHILA KANCHI — Sat, 06 Oct 2018 13:01:37 GMT

hello sir,

even i have the same doubt.. could you please help me..??

my email id is kanchin639@gmail.com

it would be kind enough if u help me..

thank you

RE: Blast analysis using Direct analysis method

Arun Sama — Tue, 24 Apr 2018 09:37:52 GMT

Sir currently iam undergoing a Thesis on Blast loading on RCC Structures using Staar Pro. Actually analysis part is completed and iam getting trouble in which results are to be taken. Blast load is evaluated on the structure using time history analysis.In Post processing mode- Dynamics - Time Displacement ,Time Velocity,Time Acceleration can be seen with variation of time.For every storey i was getting the displacements,velocity and acceleration in 3 directions x,y,z.How to take the maximum of these three graphs pls help me out sir so that I can move further in my career development

RE: Blast analysis using Direct analysis method

Arun Sama — Mon, 04 Dec 2017 07:07:01 GMT

Sir I have considered a RCC Frame structure and by using IS 4991-1968 I have calculated the blast parameters required and finally calculated Force in Kilo Newton for the Pressure on Front Face and no Pressure on Rear Face. Now I know only one point that blast loads are applied on the structure using Time History Loading in Staad Pro.Now please help me out how to give blast loading in Staad with detailed procedure or else a manual for giving blast loding using Staad. How to give Time History of Loads at Nodes ( Charge Weight-100 kg , Stand off distance - 30 m)

RE: Blast analysis using Direct analysis method

Sye — Sun, 12 Feb 2017 03:03:25 GMT

The analysis results would be different if you compare between the model you attached and the one you modified based on my earlier post. The reason being, in your model that you have attached, the dynamic analysis is not accounting for pdelta effects whereas if you follow the example I attached, such effects are being considered.

RE: Blast analysis using Direct analysis method

Florian Kolniara — Fri, 10 Feb 2017 08:32:22 GMT

communities.bentley.com/.../Blast-_2B00_-Z-LRFD_2D00_C.stdHI Sye,

Well I have followed the model example now the analysis running smoothly, but the result is different from previously run using older version. where previously the member are okay now after using the model example the UC check is failed.

attached here under the Staad files which i made originally

communities.bentley.com/.../Blast-_2B00_-Z-LRFD_2D00_C.std

RE: Blast analysis using Direct analysis method

Sye — Thu, 09 Feb 2017 18:00:51 GMT

If you are having trouble analyzing a file, that worked in older versions, in the latest version ( 20.07.11.82), please send us the file and we will a look. However for a time history loading in a file with Direct Analysis commands, please follow the example model uploaded in my last post in this thread.

RE: Blast analysis using Direct analysis method

Florian Kolniara — Thu, 09 Feb 2017 01:45:48 GMT

Thank you, this help alot.

Previously I tried to run using PERFORM DIRECT ANALYSIS command one time after load combination not after every load case and not using PDELTA KG. On the older version of STAAD.pro the command work, however after software update the same structure command is no longer work, resulted in error. Even when I opened previously run model with result, the files refused to open on latest update of staad software.

RE: Blast analysis using Direct analysis method

Sye — Wed, 08 Feb 2017 22:00:49 GMT

It would not be appropriate to do a direct analysis with a time history loading. Instead what you can do is a Direct analysis for all other cases and then analyze the time history loading using a PDELTA KG. That accounts for the pdelta effects in the eigensolution. Subsequently one can use load combinations to combine the effect of the time history loading with the other load cases. I have attached a sample model demonstrating this. Although the time history loading is a harmonic function in this case however it would be the same for a blast loading as well which will essentially be a force vs time input.

communities.bentley.com/.../Time-History_2B00_Direct_5F00_Analysis.std

I cannot think of a better option than this for now.