Here is a sentence from a news article:
As frustrating as Mikey’s days were, his experience is pretty typical. Researchers define bullying as aggressive behavior that happens again and again.
What does the as ... as mean? The closest meaning I can guess from the context is though as it is said on the OALD site, although OALD considers it a different part of speech and uses only one as:
Happy as they were, there was something missing.