Im really confused while applyling Boundary Conditions. If I apply load at one end, wont it get reacted as all the translations are fixed in a pinned support. How do i simulate this?
I have never used PATRAN, and I am probably misunderstanding your question, but ...
If ALL your translations are fixed, your axially directed load "never reaches" your column because it goes directly into the support: you need to release that axial restraint.
no, you do not fix all translations in a pinned end. you only fix the lateral translations. you do not fix the axial direction translation at both ends, only at the end that is not loaded.
as above, at one end constrain all 3 translational freedoms (X, Y, Z), at the other with load applied axially (in X?) constrain Y and Z.
now you will also need to constrain RX (if X is axial, ie column torsion) at one end, it doesn't matter which, but the fully constrained end (as opposed to the loaded end) would be more natural. This gives you 6 constraints necessary for rigid body motion.
you'll also need to run a solution that understands compression and buckling, the standard static stress solution probably doesn't understand this and will just give P/A as the answer (not appreciating Euler buckling).
BTW, PATRAN is a pre-and post-processor ... you are running some other FEA code, possibly NASTRAN.