It's cold, I know.
She's awesome, I know.
Are these comma splices? If not, what is the name of the I know clause?
Is there a name for the whole structure?
When you invert the normal order of the sentence
you need a comma to make the sense clear:
So while these appear to be two independent clauses, the first is actually a relative clause with an omitted that. Here is how the sentence would read if we were to put the that back in.
And if we were to invert that, we would have
But that sounds a little stilted to the modern ear, so we just say
In those examples, I know is a ‘tail’, a feature of speech which reinforces what is being said.