Which part of the u. s. constitution was added after ratification to address the concerns of the anti-federalists?

I think the answer is: Article of Confederation 
The anti-federalist strongly oppose the formation of a stronger government and ratification of the Constitution.
In order to address the issues, it is stated in the article of Confederation that there will be a separation of power in the government in order to make the government become weaker.

Water,oil,and