Learn English – He was elected president. VS He was elected as president

The question is broad and depending on the context, the meaning of those sentences drastically change. Since the question is broad, I'll answer that way.

Both the sentences broadly mean the same - you (at some point in time) were present at that place. However, a subtle difference is...

I was there - merely talks about the past event that you were present at that place.
I have been there - talks about the past event of you being there but also emphasize that that event has something to do in the present talk/scenario. The current scenario/talk could be the result of you being there.

as was expected means "as people expected".

as was to be expected means "as there was reason to expect"

P.S. Consider this scenario:

The hairline crack propagated and the turbine blade failed, as was to be expected.

That is, there is reason to expect any turbine blade to fail if it has a hairline crack which propagates. That is the usual result when a crack in metal is subject to further stress. There is no implication that people had advance knowledge of this particular crack.

The hairline crack propagated and the turbine blade failed, as was expected.

This would imply that there was knowledge, in advance, that the blade had a crack, and that it was expected to fail; people were waiting for the blade to fail.