How to use the "Camber for Construction Stage" option?  What is the difference between General Construction Camber and Manufacture Camber?

Creation date: 6/26/2018 8:24 AM    Updated: 4/28/2023 9:15 PM
Question:
The images below show the relevant options/output in midas Civil.




Answer:
Using the 'Camber for Construction Stage' function, you can view the displacements of the girder with respect to the camber and the effects of the camber on the member forces will be taken into account. 
Here is an example. There are three construction stages as shown below. Self-weight is the only load applied to the cantilever girder.






The vertical displacements (DZ) at the final stage are as shown below.


The construction camber can be obtained from the Results>Bridge>Camber/Reaction>General Camber.
Define General Camber Control as below. The structure group 'All' consists of all three elements.


This is the construction camber.


Now, we want to include the camber in the displacements so that we can obtain the displacements with respect to the camber. These displacements can be used to monitor the actual position of girders during erection.
Go to the Load>Construction Stage Data>Camber for C.S.
Select 'Deformation Camber' and 'General Camber' as shown below.
Select all the nodes in the model and hit the Apply button.


Click the three-dot button to see the table. These displacements correspond to the construction camber for each node.


Go to 'Construction Stage Analysis Control Data' and check on the 'Apply Camber Displacement to C.S.' option.


Perform analysis again. Then, the construction stage analysis will be performed based on the changed geometry as below.

The displacements with respect to the camber are shown below. We can see that the displacements at the final stage reach zero, which corresponds to the desired profile of the girder after construction is complete. Make sure to check the 'Including Camber Displ.' option.


You can also see the axial forces introduced in the girder due to inclined geometry.


Additionally, if the  'Using Interpolation by Key Nodes Camber' option is selected instead of 'Deformation Camber', the construction camber will be calculated as a polynomial function based on the start node, end node, and maximum camber as shown below.


The construction camber can also be directly defined using the 'User-defined camber' option.

Finally, the manufacture camber is used for shop drawing of steel girders and the construction camber is used on the construction site for formwork adjusted on-site construction.  Among these, the construction camber is used for the 'Camber for Construction Stage' function.
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