There are many websites and forums that help you to meet other expats. Meetup has different groups depending on interests, and you can meet locals as well as other expats.
How long are you planning to stay in Abu Dhabi? If you're often moving to new places, Internations is a popular site, and it's all over the globe. They often host meet-ups for expats to get to know each other and make friends.
Hope this helped!