How to design an element which has critical load in between the construction stage?

Question:

In the design of composite steel structures under different construction stages (say 10 stages) does MIDAS consider the maximum of the developed forces during stage construction and those developed under other applied loads or just the loads developed after post-construction stages? for example at construction stage (4) the developed bending moment in member (i) is 100 kip-ft. After post-construction stage the completed structure will be subjected to other loads such as live load, wind, etc. Suppose the developed bending moment at the same member (i) is now 50 kip-ft. Will the Composite Design Module deign the member for 50 kip-ft or 100 kip-ft? please explain

In reality the member shall be designed for 100 kip-ft since it is the max controlling force. If this is not the case, how can we direct the software to design for the maximum developed forces during construction? please explain

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Answer:
Hi,

The composite steel girder is designed using the combined forces of dead load at the last stage and live load, wind, etc. at the PostCS. In other words, it is assumed that the maximum forces due to dead load occurs at the last stage. Thus, the user needs to check if the maximum forces occur at the last stage. If a member is subjected to maximum force at the stage other than the last stage, the maximum forces can be applied for the design by setting the particular stage as the final stage from the 'Construction Stage Analysis Control' dialog.


Regards,
DK Lee