Structural Analysis software - Expansion joint

Hello,

I am doing my undergraduate thesis design project and facing an issue with the expansion joint. I am designing a steel frame, one bay, 40 meters x 100 meters structure. And with expansion joint building is divided into 2 separate parts. How should I deal with this on structural analysis software? Also, when I apply the loads on the structure using load panels, it is calculated the loads based on the dimensions of the separate parts. Should I add the loads manually by line loads on each frame?

Thank you for your help.