Dear Adi Singh,
Yes, 20 kN = 20,000 N is a big force. You can imagine as picking up 2 ton of something on your shoulder
. I have never involved to that line. But for that size it may be relevant. To make sure you may ask their (vendor) calculation or their such related documents.
Have you try using stopper support over there or add some flexibility. Like adding loop to reduce axial force in straight line due to temperature. Hope this works (my guess). I agree w/ you to put it as OCC load case.