deflections not looking correct in construciton staging

Question:

My deflections in my construction staging are not making sense. Deflections of 10^50 ft. I believe I set up all the boundary conditions correctly in the construction staging. not sure what is wrong.

Please do not send a revised model with a version greater than 2018 v1.2 as i will not be able to open it and can't update at this time.


Answer:
Hello,

Thank you for sending your question.


Because of the singular error, the analysis went on abnormally and there was a large deformation on the first stage.


The singular error occurred in the first stage because the deck element was not activated and then the beam girder could not resist rotation in the x axis.
In the case of the bearing, the rotation occurs in the z-axis because it resists dy only at the mid-node of the five nodes which is defined as elastic link.

Therefore, for the stage before the Deck element is activated, a temporary boundary must be set to resist Rz and Dy on the leftmost beam element.

01. Set a new boundary group (Temp.)

02. Define a boundary that resists Rz and Dy at the left end of the beam element.

03. Activate the corresponding boundary group (temp.) At the first construction stage.

04. In the third construction phase where the deck is activated, the thawing boundary group.






Thank you.
Best regards,
Jihong Hwang
Creation date: 7/24/2018 10:34 PM (dklee@midasit.com)      Updated: 7/25/2018 8:04 AM (dklee@midasit.com)
Files   
DataImage14.png
DataImage46.png
DataImage54.png
DataImage79.png
DW-TOLLWAY_MS_4300-MIDAS MODEL_20180531.mcb