Bike Storage: Wall mounts, stands, lock-ups, sheds, etc.

Can you start the hole off with a smaller drill bit?

Sounds like the drill bit is fucked. Does the head look OK? Sometimes the little brazed in bits can get damaged.
As Joeboat says, I would start with an 8mm so the big drill has a bit of an easier time.

Is it reinforced? Could have hit a bit of rebar and not have the bit for it...

Don't want to teach you to suck eggs, apologies if this is super obvious, but I have seen people drilling away at something for absolutely ages with the drill in reverse gear...

Edit: although whether it makes a huge difference when smashing in to concrete with an SDS I don't know...

I did this a couple of days ago, hired a SDS drill and bought a 16mm bit, it sook 20-30 seconds per hole for the 90mm depth, make sure you are not set to hammer only!?

was fine until i hit a metal bar and the bit gripped at an angle on the metal and jammed, put it to hammer only and yanked hard and got it free eventually.

oh and it seems that garage defenders do actually work...

I drilled 60mm deep,20mm diameter holes a couple of times, recently, to secure scaffold loops to provide secure bike locking points.
I used my own Bosch sds drill. It is notionally rated to 24mm into concrete, but I used a series of sds bits so as not to stress the mains electric motor: 6mm, 8mm, 12mm, 16mm, then 20mm.
Someone can do the maths, but this splits the volume to be removed (not equally), across the 5 drill bits.
Using this stepped approach, the drill bits almost pulled themselves into the hole, and there was easy and quick debris removal.

The concentration of the impact with a smaller diameter sds drill bit will sometimes penetrate a piece of aggregate in concrete whereas your 16mm drill bit could be ineffectively spinning on the aggregate surface.