Shell elements, FROM: ASECon

Question:

Hello,

our customer has question about shell conctructions:

1. I modeled the "rheology" of the upper bridge plate and the bottom plate in the program. Rheology was activated only for the lower plates and the upper plate on the span sections, the sections of the plate over the supports were not subjected to rheology operations due to scratching and were modeled from another material for which no rheology was assigned. 

As I mentioned, the sections of the reinforced concrete slab located near the supports wil scratch, so I would like to reduce the rigidity of the shell elements to the stiffness of the longitudinal reinforcement in the slab. Unfortunately, when activating rheology and reducing the stiffness of the plate (using the "Plate Stiffness Scale Factor" function) an error appears: “[Error] Plate Stiffness Scale Factor cannot be applied when Include Nonlinear Analysis (Accumulative Stage) or Include Time Dependent Effect option is considered in Construction Stage Analysis Control.” How can one take into account the rheology and reduce the stiffness of the top plate over the supports due to scratching.

2. Whether during the modeling of the construction technology (stages of concreting of the top panel) it is possible to activate the shell elements of the top plate adapted to the deformed geometry of the main girder.


Attached, I am sending the construction model. I will be grateful for your response.

Best regards,




Answer:

Hello,

I've simplified the questions.  The response to the issues is as below:
1)  How to reduce plate stiffness in model with construction stages and time dependent effects?
A:  As of now, this isn't possible by directly using the plate stiffness scale factors.  For such situations, I'd rather recommend to not model the plate itself, thereby making longitudinal resistance to force and bending to 0.  In such locations, it is recommended to model transverse beam elements with reduced Ixx stiffness for slab.
2)  Is it possible to activate elements in deformed location?
A:  Yes, this can be done by activating the tangential displacement option under construction stage analysis control.

Kindly note that after applying this option, when viewing the displacement, the Stage/Step read displacement has to be chosen.
Kindly let us know if further assistance would be required.

Regards,
Nandeep
Technical Manager, MIDAS
Creation date: 10/3/2018 11:27 PM (dklee@midasit.com)      Updated: 10/4/2018 8:58 AM (dklee@midasit.com)
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