It partly depends too on how healthy/vigorous the fermentation was (which is a good indicator of overall yeast health and numbers) and how long the beer has sat before bottling. For some of my high gravity beers I let them bulk age in secondary for months before bottling. I always add new yeast to these. But if you have only let it sit for a few weeks and had a good fermentation, your yeast are probably fine. However, the bigger beers tend to take longer to carb up - at 10% ABV, even healthy yeast are in less than ideal shape. Patience is key.