Vrip equation doesn't seem to work
Where is the circuit GND reference connected in your simulation circuit? If it is connected to one side of the AC source then this could explain the behavior that you are seeing. The same thing that was noted in this question:

Diode Bridge in Simulator not behaving as expected

Update

Upon seeing the actual simulation circuit I can see that the reference point GND is indeed tied to one side of the AC source. Replace the connection from the bottom side of your AC source over to the connection between D2 and D3 where it should be. You have not constructed a correct bridge rectifier as shown.