It's extremely possible to expand the capacity of the Emirates. There were allegedly plans to do so last summer by narrowing the seats: http://news.arseblog.com/2013/04/arsenal-set-to-extend-stadium-capacity/ Anyone who has been to a game will tell you it's plenty spacious. Even just removing 1 inch from each seat you'd add a reasonable amount of extra capacity.
This was an April Fools article....Though I was actually thinking yesterday that that would be one to add new seats, by narrowing the ones we currently have.
From which engineering perspective is it possible expand to expand the stadium? We will be watching the CL final tonight.The Estadio de Luz was drsdigned by the same architects as the Emirates.You will notice the stadium has the corners missing the same as the Emirates.One can only assume the corners are missing for the same reason
As I understand it the Emirates capacity can be increased to 90k by banning fat bastards from the ground
Cym is right, the corners of Emirates were designed that way to allow air flow to the pitch in order to maintain the right conditions for the turf.