This is the 254th most frequent Turkish word.
yapılan
"Yapılan" means "done" or "made" in English.
In this sentence, 'yapılan' acts as an adjective describing 'işlerin' and denotes a passive action performed previously (things done).
Bu, yapılan işlerin sonucudur.
This is the result of the things done.
Here, 'yapılan' modifies 'bina' and refers to a recent action (constructed) completed passively.
Yeni yapılan bina çok güzel oldu.
The newly constructed building turned out very beautiful.
In this case, 'yapılan' describes 'konuşmalar', indicating the speeches delivered passively during the event.