"The bridge finished" and "The bridge been finished".

[Vik PRINCiplE]

Hey, guys, I've suddenly been s(t)uck in an unsolvable problem for me, LOL... A Russian friend asked me what'a difference and I can't explain it. No idea. I.e. 'The finished bridge' and 'the bridge been finished' - he says it's no difference 4 him and I kinda can't explain that it is! Grammar doesn't help me either - I think he just doesn't understand the perfectness of the past action.

 

[emsr2d2]

Hey, guys, I've I have suddenly been s(t)uck in an unsolvable problem. for me, LOL...

Don't refer to everyone here as "guys". We're not all male. You haven't been stuck. You are stuck. However, as you can see above, it's more natural to just say you have a problem.

A Russian friend asked me what'a the difference between two sentences and I can't explain it.

See above.

I have no idea.

Always write full sentences on the forum.

I.e. For example:
1. 'The finished bridge.' and
2. 'The bridge been finished.'

See above. Whenever you give us more than one example to consider, number them.

He says it's there's no difference in meaning 4 for him and I kinda can't explain that it there is!

See above. Don't use numbers instead of words and don't use non-standard words such as "kinda" here. We're not teenagers in a chatroom!

Grammar doesn't help me either - I think he just doesn't understand the perfectness of the past action.

I don't know what you mean by "Grammar doesn't help me either". Do you mean you haven't been able to find a grammatical explanation for him?

Anyway, on to the question itself. There is one striking similarity between the two sentences you posted - they're both ungrammatical.
"The finished bridge" is not a complete sentence. Those three words could be used in that order inside a longer sentence.
"The bridge been finished" is incorrect. I suspect you meant "The bridge has been finished", which is a grammatically correct sentence.

Until you give us a grammatical version of sentence 1, there's no way for us to tell you whether it's similar or different in meaning from sentence 2.

 

[Piscean]

Are you sure you are a retired English teacher and a native speaker of English, @Vik PRINCiplE?

 

[jutfrank]

I'm detecting a completely different question from the one emsr2d2 has answered above. I don't think you're asking anything about sentences, but rather about the noun phrase the finished bridge, which is a way to refer to a particular bridge that has just been built.

a) the finished bridge
b) the bridge finished
c) the bridge been finished

Obviously, as a retired native-speaking English teacher you'll know that b. and c. are completely wrong. Your friend might be translating incorrectly from Russian.