Thanks for posting!
Building 80 (SAB - Swanston Academic Building) should be open for general access from 7am - 9pm, Monday to Friday.
Saturday times for general access will depend on class bookings, however the IT Service Point on level 3 is open from 8:30am - 4:30pm and the building can generally be accessed during this time.
For further clarification, you can contact RMIT Security:
Hope this helps you out!