After fixing the elevator on your way to the radio in the fort, you may soon find yourself at another impasse in Amnesia: Rebirth.
On the second floor of the building you’re in, you’ll find that the only way to proceed in Amnesia: Rebirth is to break a bit of the floor that has already been weakened. And unfortunately, jumping up and down on it doesn’t do the trick. You’re going to need something heavier.
To break the floor in the fort, you need to make use of the cannon that’s just in corridor across from it. Try to push it as is, however, and you find that you can’t move it as it only has two wheels. You’re going to need to replace them if you want to make use of it.
Luckily for you, one wheel is right next to the cannon – find it, grab it and then put in on. Another is in a nearby room with two cannons. Carry it back and place it on the broken cannon to be able to push it forward and break the floor.