Interesting Roof Structures

I am an undergraduate student studying towards an MEng degree in Civil Engineering at the University of Glasgow. As part of my 4th year dissertation I am looking into roof structures in particular where a roof has been added to pre-existing buildings to cover a public space. The reason for this is to asses options for putting a roof over Buchanan Street in Glasgow (a popular shopping location in Glasgow's city centre).

I have found one example of such a project in the Victoria Quarter in Leeds along with a few others however I was wondering if anybody knew if any similar pieces of engineering existed anywhere else in the world. Also of interest to me are any interesting/innovative roof systems in general or any good texts relating to roof systems.

Thanks in advance for any replies it would help my studies greatly.