Displacement to be considered for camber

Question:

Hi
We are doing preset analysis for a canopy structure.
We have checked the "Initial Tangent Displacement for Erected structures" in the Construction Stage Analysis Control.


We would like to know which displacement to be considered for deformation results: normal displacement we consider in the post-processing stage or stage/stage real displacement in the last construction stage?

Thanks



Answer:

Hi User,
Thanks for writing to us!

Generally, we need to consider tangent displacement as we do not adjust the form-work while casting the next segments, So we provide the 'camber' based on the displacements-which include CS displacements+tangent displacements.
So, we need to consider 'stage/stage real displacement in the last construction stage'.
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Detailed Explanation of Deformation in midas Civil

Joint: where next segments of CS2 are added to the already activated segments of CS1.

Generally, in the analysis, when new segments are activated, the joints enter at the location that was initially given to them in the input data (at the original position), thereby creating the discontinuities at the joint locations.

1) One way to avoid these discontinuities is to rather apply the new segments tangentially than straight-forward.
2) Another way is to calculate the tangent displacement and add it to the CS-displacement. (This feature is implemented in midas civil to auto-calculate the tangent displacements).

We can have three possible deformation configurations in construction stage analysis. Usually, in our daily projects we match cast the segments, hence tangent displacements need to be considered.


In MIDAS/Civil using the option initial tangent displacement for erected structures for the construction stage analysis, the real displacement may be calculated for all members or for specific groups only. If this option is not chosen all segments will be applied straight-forward(standard cast- first sequence in the above figure) instead of tangentially and a discontinuity is introduced at the joints between the segments.


In your structure, if the real construction sequence is of match-cast, then we need to take 'stage/stage real displacement', which include tangent displacements.
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kindly go through this interesting video to understand the difference.
Link:
https://www.youtube.com/watch?v=-M_DfsDnKKI

Hope this clarifies!

Regards,

Creation date: 8/13/2018 7:23 AM (suman)      Updated: 8/13/2018 4:54 PM (suman)
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