Hello Darren,
The 3850 supports per VLAN QoS so you have a couple of options. You could shape each VLAN to 1 Gbit but that means that VLAN never gets to go above 1 Gbit…is that what you are looking for? Instead of shaping, you also could use a policer which drops the traffic.
You might also want to look at some nested policies. For example, when you shape up to 1 Gbit, you might want to prioritize sensitive traffic like VoIP.
Rene