Hello,
I have been working on blast analysis on steel structure building on one of my projects,
On design basis direct analysis method and ASCE blast load is required to be used during building design
I have been trying to use direct analysis method using time series blast load case but the STAAD software always resulting in error during analysis if direct analysis is performed, while the analysis is running fine if direct analysis is not used.
My question is as follows:
Can Blast analysis (time series-force) performed using direct analysis?
Thank you inn advance,
Best Regards
Florian O
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.
Time History+Direct_Analysis.std
I cannot think of a better option than this for now.
Blast + Z LRFD-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
Blast + Z LRFD-C.std
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.