Treated pine deck

[groo]

My hardwood back deck has succumbed to the elements and I will be replacing it with treated pine (90 x 22 boards).
Bearers (1.5 m apart) look fine but joists (100 x 50 at 450 centres) will have to be replaced.
What size treated pine should I use to replace these joists? Would 90 x 45 do?

Many thanks in advance.

[manoftalent]

in one word ....yes .....but double check on the bearers ....make sure they are solid