If one thinks of an elevator is an extremely complex “pulley system”, it becomes apparent that the load will primarily act at the point of fixity (i.e. roof level).
The load is actually much higher than lift capacity as Elevator suppliers it includes the weight of personnel (max), equipment, the counter-weight + dynamic amplifications (including impact).
All of the above are product specific and so maybe that’s why there is no standardization of elevator loads in codes (I’m not aware of any).
Here is a sample picture of the system I found online
Based on this, I think it would be wise to apply the total load (as given by the lift manufacturer) on the roof slab and design for it.
Disclaimer: Unfortunately I have not had the Best elevator company pleasure of designing any building with an elevator system so I cannot provide you specific design procedure but I am positive it must be pretty close to what’s mentioned above (get the loads from the manufacturer and apply those on the roof slab).