topic Partial Seismic Analysis - 'greyed out' structure is not editable in Robot Structural Analysis Forum

Partial Seismic Analysis - 'greyed out' structure is not editable

ALJohns — Mon, 17 Oct 2016 23:48:54 GMT

Hi Guys

I am considering a bridge crossing 4 rail lines.

In addition to standard loading (Dead, Live, Wind, Earthquake, Thermal etc.), I am considering a derailment case. The bridge has 2 central piers, and during the derailment case, it is assumed the central supports are compromised and the bridge spans across the 4 rail lines (with reduced live loading).

To analyse this, I have set up 2 similar models: The first is for checking all of the standard loads, the second is for checking the case with reduced supports (considering vertical loads only). My problem occurs when I set up seismic loads and define stories. I want to exclude the second model from seismic loading, but when I do, the second model is 'greyed-out' and is not editable (even for the standard load cases).

I have attached a screenshot with more details.

Thanks for your help.

Aaron.

Re: Partial Seismic Analysis - 'greyed out' structure is not editable

Artur.Kosakowski — Tue, 18 Oct 2016 07:51:49 GMT

I suggest defining the models in the separate files.

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Re: Partial Seismic Analysis - 'greyed out' structure is not editable

ALJohns — Tue, 18 Oct 2016 23:09:46 GMT

Thank for the response Artur.

I was hoping to keep the two models in one file so that I can group similar members and run the steel verification and design for both models at the same time.

Can you explain the purpose of 'stories - advanced options' if it isn't used to isolate the extent of the seismic analysis?

Also, why is the structure 'greyed-out' for the standard load cases? Is this a bug, or is it indicating a modelling error?

Thanks for your help

Aaron

Re: Partial Seismic Analysis - 'greyed out' structure is not editable

Artur.Kosakowski — Wed, 19 Oct 2016 07:41:14 GMT

Can you explain the purpose of 'stories - advanced options' if it isn't used to isolate the extent of the seismic analysis?

Could you attach the file? I initially assumed that you defined the response spectra analysis but perhaps you actually used the Equivalent Lateral Force Method instead?

Also, why is the structure 'greyed-out' for the standard load cases? Is this a bug, or is it indicating a modelling error?

I assume you just have the story filer applied.