Imperial stout didn't carbonate

I made an imperial stout that tastes fantastic but has very low carbonation despite me putting in the right amount of sugar pre-bottling. It’s the highest ABV I’ve done (just over 8), and I’m wondering if that kept my yeast from doing their thing. Thoughts? Is there an extra step to take with higher ABV? Something I could do to salvage this one?

I do recognize kegging  saves me this problem!

High gravity beers often take considerably longer to carbonate than their low ABV cousins. If they are partially carbonated more time will likely get them to the level you primed for.

How long did you condition? We had a tripel once that took almost a year to carbonate. It may just need more time as mentioned above.