If you want to perform the serviceability limit state design, you can define the limit values to be checked in the serviceability configuration. For example, the vertical deflection of the steel bridge should be limited to l/200. To do this, you can connect the members of the bottom chords to form two member sets, or check the deflection of the central members with a length of 18 m. Only the second approach is described in this manual. More information about member sets can be found here.
Select one of the middle members on each bottom chord and open the "Edit Members" dialog box. In the "Design Support and Deflection" tab, you can specify your own details of the deflection analysis. Among other things, you can enter the length that should be considered in the design instead of the actual member length.
You can select and edit the "Serviceability Configuration" in the "Design Configurations" tab.
A dialog box appears where you can enter the limit values for the design and assign the configuration to both middle members.
