Camber for Construction Stage

Question:

There is nothing in the manual to explain how to implement this option "Camber For Construction Stage" ? I am trying to run construction stage analysis for steel composite structure. Please explain in details with examples what needed to be input here to make sure that camber is taken into account.

Also, the second pictures shows the resulted camber for girder 4 after Construction Stage Analysis. What is the difference between "General Construction Camber" and "Manufacturer Camber" ? . How this information can be used in "Camber for Construction Stage"? Please explain the process in details so that I can apply the concept !

Model file is enclosed





Answer:
Hi,

Using the 'Camber for Construction Stage' function, you can view the displacements of the girder with respect to the camber and the effects of 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 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 corresponds 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 as below. We can see that the displacements at the final stage reach zero, which corresponds the desired profile of 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 user selects the 'Using Interpolation by Key Nodes Camber' option instead of 'Deformation Camber', the construction camber will be calculated as polynomial function based on start node, end node and max. camber as shown below.


Or the construction camber can be directly defined using the 'User defined camber' option.

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

Regards,
DK
Creation date: 6/26/2018 8:24 AM (dklee@midasit.com)      Updated: 6/26/2018 5:55 PM (dklee@midasit.com)
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Staged Construction_Chinese_LRB.mcb