At max take off power, there is a constant force on the pylon, created by the thrust of the engine. For an A380 this is about 30 tonnes of force.
As stated above, approx 80% comes from the fan, 20% from the core efflux.
In simple terms....
24 tonnes of this thrust comes from the fan, hence there is a force of this amount acting on the LP bearing.
6 tonnes come from the hot high pressure gases exiting the combustion chamber through the turbines. The turbines don't create any forward thrust. All the HPT and IPT do is compress the inlet air. All the LPT does is turn the fan. The turbines just absorb the heat & pressure energy of the combustion chamber gas and turn it into rotational force.
(there is an axial drag force on the turbines, but this serves no useful purpose)
Hope this helps.