Most of the large construction projects are run by Chinese companies, especially the Chinese State Construction Corp. New airport terminal, ministries, hotels, convention center, light rail, and so on. This has caused some discussion around Chinese taking construction jobs etc. You'll see these state-funded Chinese construction projects in pretty much every African country.
Although Addis is booming, the population still primarily lives in the countryside, and their quality of life is a lot lower. It's misleading to look at average income across the entire population because the city's economy is so far ahead of the rest of the country. This has probably contributed to some of the unrest.