I need to consider construction stages in my model of a high-rise building. There are levels with outriggers, so if I don't do that and apply whole dead load at once to a complete model, columns below levels with outriggers turn out to be in tension, what is obviously does not represent the "reality". In order to avoid that, dead load has to be applied as the building goes up, i.e. I need to consider load sequencing.
I tried phases in robot, but I think they are not applicable here. Robot treats each phase as a separate model, and there is no connection between them in terms of loading.
Anyone has an idea how to implement staged construction/load sequencing in robot?
Solved! Go to Solution.
I've been able to do a staged analysis taking into account load sequence in Robot using information from individual models (note that bar elements must have the same number in all models). Due to the great amount of data that you need to save for each stage, I ended up writing a program.
Load sequence in phases can be considered applying the self-weight load only to the story added in the appropriate phase. Then, after collecting all phases with the most complete phase treated as the base one, it is necessary to define a combination of these self-weight cases from all phases. It is illustrated on the screen capture below.
As concerns displaying results for such combination of results from various phases it is necessary to use RSA 2014 with Service Pack 3.
In previous versions Robot was able to display results for such combinations only for elements existing in all phases considered in the combination - so in practice only for the bottom story in the above example
Thank you for your response!
To clarify, if after doing all this I want to use total dead load (with load sequencing) in load combinations, what should my approach be? Should I create design combinations for every phase? Or there is another faster way of doing that?
I'm a bit confused...
If these combinations "between phases" are related only to some types of loads (usuallly selfweight) then there are some ways to simlify it, like for instance:
1/ defining design combinations in one phase - usually the most complete one, used as a base phase during collecting. In these combinations selfweight from this phase can be used
2/ after analysis and collecting of phases defining in the collected phase the combination of selfweight cases from various phases as mentioned by me before
3/ in the collected phase modifying the combinations defined in step 1/ in such way that the selfweight case from the base phase will be replaced by the combination defined in step 2/. Such modification can be done on the Edit tab of the table of combinations.
What is important in case of phase structures is that after any modification in any phase it is necessary to repeat analysis and to collect phases again - so steps 2/ and 3/ have to be repeated too
Some improvement wish related to it is registered there.