I’m not a lawyer and I don’t know the legal term but basically the charge is blocking access to a public location, or trespassing if it’s a private location. If you’re doing it in a congressional or government office then it’s something like “impeding the function of a government office/official”.

There’s probably other terms but 9 times out of 10, for protests in DC, whether it’s a sit-in in a congressional office or on the steps of the Capitol, they don’t charge you. It’s not worth their time or the court’s time and you’ve likely made your point. If they arrest you and notice its your 20th or whatever time doing this, you may face charges, or some jail time but again, it’s DC. People protest things. If you aren’t destroying property or threatening officials, they really don’t care all that much. It’s very routine for them.

There used to be a woman who camped out in a tent front of the White House for literal years, protesting all sorts of stuff. She was never in anyone’s way so she was left alone until she died there.