As like above title, I want to check the Contact Pressure between two surfaces which tightened by tie-bolt.
Each surfaces are contacted by slide and connected by some tie bolts which have pretension load.

Until now, I used the CONTF card to check the contact pressure. However, The result was a little bit different from what i thought.

If contact traction SPOS/Normal(Pressure) is really contact pressure, it might be show no negative value .
So, I am confused.
How can i check the Contact Pressure?