The sentence ""That bridge has been being repaired for the past ten years" is ambiguous. It is unclear if the work started 10 years ago and has not been completed, or if multiple repairs have been made over the ten year span. Furthermore if multiple repairs have been made, it is unclear if the bridge is now repaired or not.
The sentence "That bridge has been repaired for the past ten years" is ambiguous to me too. It definitely means that the bridge is now repaired. But it is unclear if the repairs were completed 10 years ago or if the bridge has been repaired multiple times within the ten year span.
Ok, let's beat this to death so more.
The bridge was repaired 10 years ago.
It is isn't clear if this was the first repair of the bridge, the last, or some intermediate repair. It is also unclear if the bridge needs repair now or not. But 10 years some repairs were made and completed.
The bridge was last repaired 10 years ago.
The last time the bridge was repaired was 10 years ago and those repairs were completed. There may have been previous repairs. It is unclear if the bridge needs repair now or not.
The bridge was last repaired 10 years ago and it is still serviceable.
The last time the bridge was repaired was 10 years ago. There may have been previous repairs. The bridge does not need repair now.
The bridge, now repaired, ...
The bridge does not need repairs now.
The repairs on that bridge started ten years ago and the repairs are still are not finished.
The repairs started 10 years ago and were never completed over the 10 year span.
That bridge started "being repaired" ten years ago.
Repairs were started 10 years ago and have never been finished.
That bridge has been being repaired multiple times over the past ten years.
Over the last 10 years multiple repairs have been completed on the bridge. It is unclear if the bridge needs repair now or not.
No, I don't think that your interpretation is correct.
To make things a little clearer, let's replace had with employed.
To say:
Fred is the best minister we have ever employed
suggests that you are still employing Fred as a minister, although it's possible that Fred is still a minister but no longer in your employ.
Your other two examples both indicate that Fred is no longer in your employ, regardless of whether he is still a minister.
To add ever merely adds emphasis. It does not change the meaning of the statement.
Neither of the two examples indicates whether Fred was your last minister or whether you have employed other ministers subsequently. It's possible that he was the first minister and that there have been others; or that he was the last minister; or merely one of several ministers. Your examples leave this open.
Best Answer
under construction almost always implies something is being built for the first time. It has become a commonplace phrase regarding web sites.
renovation always refers to major repair or overhaul of something that already exists.
One can renovate a site. In that case it is being refreshed, not undergoing its initial establishment.
Both terms traditionally referred to building things like houses, bridges, or roads. They pretty much maintain their traditional meaning when applied to web sites.