Kahroba,
I made a quick test model to try out contact and added four contact pairs to pick up the first four contacts that are made.
My model is different from what you want. I made fixed supports of all the ribs on the bottom and brought all the top ribs down by 10 mm in Y while holding X and Z fixed at 0. However, it allowed me to test the contact, which worked quite well.

Attached is an ANSYS 19.1 archive.
Regards,
Peter