In order to analyze the deflection of the mid-span with steel design, you can create a new member set with the members that form the mid-span (members 2 and 5 of your model).
test_deflections_.rf6 (1.2 MB)
In order to analyze the deflection of the mid-span with steel design, you can create a new member set with the members that form the mid-span (members 2 and 5 of your model).
test_deflections_.rf6 (1.2 MB)